CLF10040T-4R7N-D

R1276S-Y NISSHINBO | Alldatasheet

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30 V , 3 A Synchronous Step-down DC/DC Converter for Industrial Applications

No. EY-404-201112 The R1276S is a 36-V rated synchronous step-down DC/DC converter with built-in transistor. Under cranking condition, the switching frequency is automatically reduced to keep output voltage level constant. This is a high-reliability semiconductor device for industrial application ( -Y) that has passed both the screening at high temperature and the reliability test with extended hours

H igh efficiency of 95%
Maintains the output voltage constant at cranking by reducing a switching frequency to the minimum 1/4.
Achieves the EMI noise reduction by using a spread spectrum clock generator. (Diffusion Rate: +10%).
Input Voltage Range (Maximum Ratings):

3.6 V to 30 V (36 V)

Start-up Voltage: 4.5 V
Standby Current: Typ. 4 µA
Output Voltage Range: 0.7 V to 6.5 V
Feedback Voltage: 0.64 V ±1.0%
Consumption Current at No Load (at VFM mode): Typ. 12 μA
Adjustable Oscillator Frequency Using External Resistors: 250 kHz to 1 MHz(1)
External Synchronous Clock Frequency: 250 kHz to 1 MHz
Spread Spectrum Clock Generator (SSCG): Diffusion Rate Typ. +10%
Minimum ON-Time: Typ. 70 ns
Minimum OFF-Time: Typ. 120 ns
Duty-over: Min. 1/4
Soft-start
Thermal Shutdown: Tj = 160°C
Undervoltage Lockout (UVLO): VCC = 3.3 V (Typ.)
Overvoltage Lockout (OVLO): VIN = 35 V (Typ.)
Overvoltage Detection (OVD): FB Pin Voltage (VFB) +10%
LX Current Limiting: Typ. 4.2 A
Over-current Protection: Hiccup-type
High-side Transistor ON Resistance:Typ. 0.145 Ω
Low-side Transistor ON Resistance: Typ. 0.095 Ω Efficiency (VOUT = 5 V) Select the optional functions from below. Product Name Output voltage range R1276S001∗ 3.15 V < VOUT ≤ 6.0 V R1276S002∗ 6.0 V < VOUT ≤ 6.5 V R1276S004∗ 0.7 V ≤ VOUT ≤ 3.15 V Product Name Over-current Protection SSCG R1276SxxxA Hiccup-type Disable R1276SxxxC Hiccup-type Enable HSOP-18 5.2 x 6.2 x 1.45 (mm)
FA Equipment, Smart Meters
Surveillance Cameras and Vending Machines that are used outside or under high-temperature conditions
Motors and Lightings that are accompanied by self-heating (1) The adjustable oscillation frequency range becomes 250 kHz ≤ fOSC ≤ 600 kHz when 0.7 V ≤ VOUT < 3.3 V. OVERVIEW KEY BENEFITS KEY SPECIFICATIONS TYPICAL CHARACTERISTICS PACKAGE OPTIONAL FUNCTIONS

APPLICATIONS

0.1 1 10 100 1000 10000 efficiency (%) Iout (mA) VIN = 12V fosc = 250kHz MODE=L MODE=H

No. EY-404-201112 SELECTION GUIDE The Output voltage range, the Optional functions and Quality class are user-selectable. Selection Guide Product Name Package Quantity per Reel Pb Free Halogen Free R1276Sxxx∗-E2-YE HSOP-18 1,000 pcs Yes Yes xxx：Select an output voltage range from below. xxx Output voltage range 001 3.15 V < VOUT ≤ 6.0 V 002 6.0 V < VOUT ≤ 6.5 V 004 0.7 V ≤ VOUT ≤ 3.15 V ∗：Select an optional function from below. ∗ Over-current Protection SSCG A Hiccup-type Disable C Hiccup-type Enable

No. EY-404-201112 BLOCK DIAGRAM INT Regulator S PGOOD BST LX Q R VCO Hiccup (7.5 msec OFF) Slope Peak Current Limit FB RT CSS/TRK Soft Start Circuit Reference PFCMODE Under Voltage Detection UVD Thermal Shutdown CE 1.2V SHDN OVD UVD VOUT SHDN Mode Select Filter Mode Mode ILIM Drive Circuit VCC Regulator VCC Int_Reg VIN OVD VCC VFM ControlMode Rev Set_Pulse Set_Pulse VOUT VIN Reverse Detection Mode GND Rev SHDN OVD VIN VOUT COMP Over Voltage Detection OVD OFF_PulseSoft_Start OFF_Pulse Int_Reg Soft_Start 2uA Freq Detection Freq_NG UVLO VCC Hiccup SHDN OVD SHDN UVDHiccup Soft_Start CLK SSCG_EN <Enable/ Disable> Freq_NG R1276S Block Diagram

No. EY-404-201112 PIN DESCRIPTIONS Top View Bottom View R1276S (HSOP-18) Pin Configuration ∗ The tab on the bottom of the package is substrate level (GND). It must be connected to the ground plane on the board. R1276S Pin Descriptions Pin No. Pin Name Description 1, 2 VIN(1) Power Supply Pin

3 NC Not Connected

4 CE Chip Enable Pin, Active-high

5 CSS/TRK Soft-start Adjustment Pin

6 COMP Capacitor Connecting Pin for Error Amplifier’s Phase

7 FB Feedback Input Pin for Error Amplifier

8 PGOOD Power Good Output Pin

9 VOUT Output Voltage Feedback Input Pin

10 MODE Mode Setting Input Pin

11 RT Oscillator Frequency Adjustment Pin

12 VCC VCC Output Pin

13 BST Bootstrap Pin

14, 15, 16 GND(1) GND Pin

17 NC Not Connected

18 LX Switching Pin

(1) The pins with the same name should be connected together.

No. EY-404-201112 Equivalent Circuits for the Individual Terminals CE VIN Int_Reg CSS /TRK VIN Int_Reg Equivalent Circuit for CE Pin Equivalent Circuit for CSS/TRK Pin COMP FB Int_Reg VCC Equivalent Circuit for COMP Pin Equivalent Circuit for FB Pin PGOOD VOUT VIN Equivalent Circuit for PGOOD Pin Equivalent Circuit for VOUT Pin

No. EY-404-201112 MODE VCC RT Int_Reg Equivalent Circuit for MODE Pin Equivalent Circuit for RT Pin VCC VIN BST VCC LX Equivalent Circuit for VCC Pin Equivalent Circuit for BST Pin LX VIN Equivalent Circuit for LX Pin

No. EY-404-201112 ABSOLUTE MAXIMUM RATINGS Absolute Maximum Ratings Symbol Parameter Rating Unit VIN VIN Pin Input Voltage −0.3 to 36 V VCE CE Pin Voltage(1) −0.3 to VIN+0.3 ≤ 36 V VCSS/TRK CSS/TRK Pin Voltage −0.3 to 3 V VOUT VOUT Pin Voltage −0.3 to 16 V VRT RT Pin Voltage −0.3 to 3 V VCOMP COMP Pin Voltage(2) −0.3 to 6 V VFB FB Pin Voltage −0.3 to 3 V VCC VCC Pin Voltage −0.3 to 6 V VCC Pin Output Current Internally Limited mA VBST BST Pin Voltage LX−0.3 to LX+6 V VLX LX Pin Voltage(1) −0.3 to VIN +0.3 ≤ 36 V VMODE MODE Pin Voltage −0.3 to 6 V VPGOOD PGOOD Pin Voltage −0.3 to 6 V PD Power Dissipation Refer to Appendix “POWER DISSIPATION” Tj Junction Temperature Range −40 to 150 °C Tstg Storage Temperature Range −55 to 150 °C ABSOLUTE MAXIMUM RATINGS Electronic and mechanical stress momentarily exceeded absolu te maximum ratings may cause permanent damage and may degrade the lifetime and safety for both device and system using the device in the field. The functional operation at or over these absolute maximum ratings is not assured. RECOMMENDED OPERATING CONDITIONS Recommended Operating Conditions Symbol Parameter Rating Unit VIN Operating Input Voltage 3.6 to 30 V Ta Operating Temperature Range −40 to 125 °C RECOMMENDED OPERATING CONDITIONS All of electronic equipment should be designed that the mounted semiconductor devices operate within the recommended operating conditions. The semiconductor devices cannot operate normally over the recommended operating conditions, even if they are used over such conditions by momentary electronic noise or surge. And the semiconductor devices may receive serious damage when they continue to operate over the recommended operating conditions. (1) It should not exceed VIN + 0.3 V. (2) It should not exceed VCC + 0.3 V.

No. EY-404-201112

ELECTRICAL CHARACTERISTICS

VIN = 12 V, VCE = VIN, unless otherwise specified. The specifications surrounded by are guaranteed by design engineering at −40°C ≤ Ta ≤ 125°C. Symbol Parameter Conditions Min. Typ. Max. Unit VSTART Start-up Voltage 4.5 V VCC VCC Pin Voltage (VCC-GND) VFB = 0.672 V, VMODE = 5 V 4.75 5 5.25 V ISTANDBY Standby Current VIN = 30 V, VCE = 0 V 4 30 µA IVIN1 VIN Consumption Current 1 at PWM switching stop R1276S001x R1276S002x VFB = 0.672 V, VMODE = 5 V, VOUT = VLX = 5 V 1.0 1.35 mA R1276S004x VFB = 0.672 V, VMODE = 5 V, VOUT = VLX = 1.5 V 1.6 1.95 IVIN2 VIN Consumption Current 2 at VFM switching stop R1276S001x R1276S002x VFB = 0.672 V, VMODE = 0 V, VOUT = VLX = 5 V 12 60 µA R1276S004x VFB = 0.672 V, VMODE = 0 V, VOUT = VLX = 1.5 V 42 92 VUVLO1 Undervoltage Lockout (UVLO) Threshold VCC, Falling 3.1 3.3 V VUVLO2 VCC, Rising 4.3 4.5 V VOVLO1 Overvoltage Lockout (OVLO) Threshold VIN, Rising 33.6 35 36 V VOVLO2 VIN, Falling 32 34 V fOSC0 Oscillator Frequency 0 RRT = 121 kΩ 225 250 275 kHz fOSC1 Oscillator Frequency 1 RRT = 29 kΩ 900 1000 1100 kHz fSYNC Synchronizing Frequency fOSC reference when 250kHz ≤ fSYNC ≤ 1MHz fOSCx0.5 fOSCx1.5 kHz tSS1 Soft-start Time 1 VCSS/TRK = “OPEN” 0.36 0.75 ms tSS2 Soft-start Time 2 VCSS/TRK = 4.7 nF 1.4 2 ms ITSS Soft-start Pin Charging Current VCSS/TRK = “GND” 1.8 2 2.2 µA VSSEND CSS/TRK Pin Voltage at soft-start stop VFB VFB +0.03 VFB+0.06 V RDIS_CSS CSS/TRK Pin Discharge Resistance VIN = 4.5 V, VCE = 0 V, VCSS/TRK = 3 V 2 5 kΩ ILXLIMIT LX Current Limiting High-side Transistor, DC current, VMODE = 5V 3.36 4.2 5.58 A IREVLIMIT Reverse Current Limiting Low-side Transistor, DC current, VMODE = 5V 1.7 3.5 A VCEH CE Input Voltage, “High” 1.25 V VCEL CE Input Voltage, “Low” 1.1 V ICEH CE Input Current, “High” VIN = VCE = 30 V 1.2 2.45 µA ICEL CE Input Current, “Low” 0 0.1 µA All test items listed under Electrical Characteristics are done under the pulse load condition (Tj ≈ Ta = 25°C).

No. EY-404-201112 VIN = 12 V, VCE = VIN, unless otherwise specified. The specifications surrounded by are guaranteed by design engineering at −40°C ≤ Ta ≤ 125°C. Symbol Parameter Conditions Min. Typ. Max. Unit IFBH FB Input Current, “High” VFB = 0.672 V −0.1 0 0.1 µA IFBL FB Input Current, “Low” VFB = 0 V −0.1 0 0.1 µA VMODEH MODE Input Voltage, “High” 1.40 V VMODEL MODE Input Voltage, “Low” 0.74 V IMODEH MODE Input Current, “High” VMODE = 5 V 6.25 14.0 µA IMODEL MODE Input Current, “Low” VMODE = 0 V −0.1 0 0.1 µA TTSD Thermal Shutdown Temperature Threshold Rising 150 160 °C TTSR Falling 125 140 °C VPGOODOFF PGOOD “Low” Output Voltage VIN = 3.6 V, IPGOOD = 1 mA 0.25 V IPGOODOFF PGOOD Pin Leakage Current VIN = 30 V, VPGOOD = 6 V 100 nA VFBOVD1 FB Pin Overvoltage Detection (OVD) Threshold VFB, Rising VFB x1.060 VFB x1.10 VFB x1.140 V VFBOVD2 VFB, Falling VFB x1.024 VFB x 1.07 VFB x1.111 V VFBUVD1 FB Pin Undervoltage Detection (UVD) Threshold VFB, Falling VFB x0.860 VFB x 0.90 VFB x0.946 V VFBUVD2 VFB, Rising VFB x0.895 VFB x 0.93 VFB x0.974 V All test items listed under Electrical Characteristics are done under the pulse load condition (Tj ≈ Ta = 25°C).

No. EY-404-201112 TYPICAL APPLICATION CIRCUIT MODE CSS/TRK GND LX RTOP RBOT 39kΩ RCCC RPG 100kΩ CBST 0.1µF CVCC 1.0µF L COUT CIN 21µF (10x2+1µF) VOUT CE PGOOD COMP VOUT FB CSS 15nF CC2 NC VIN VCC BST R1276Sxxxx VIN GND RT GND NC RRTCSPD RCE 1kΩ CE Control R1276S Typical Application Circuit R1276SxxxA/C Constant Table Code (xxx) FOSC [kHz] VOUT [V] L [µH] COUT [µF] CSPD [pF] RTOP [kΩ] RRT [kΩ] RC [kΩ] CC [nF] CC2 [pF] 001 250 3.3 15 200 (100×2) 100 162 (150+12) 121 (220ǁ270) 22 10 100 5.0 22 200 (100×2) 100 267 (240+27) 121 (220ǁ270) 27 10 100 500 3.3 10 66 (22×3) 22 162 (150+12) 56 22 3.3 33 5.0 10 100 22 267 (240+27) 56 22 4.7 33 1000 3.3 4.7 48.7 (22×2+4.7) 22 162 (150+12) 28.7 (220ǁ33) 12 3.3 15 5.0 4.7 48.7 (22×2+4.7) 22 267 (240+27) 28.7 (220ǁ33) 12 3.3 15 002 500 6.5 15 147 (100+47) 22 357 (330+27) 56 22 4.7 33 004 250 0.7 3.3 430 (100+330) 1500 3.7 (2.2+1.5) 121 (220ǁ270) 5.1 47 150 ǁ: Parallel connection

No. EY-404-201112 Selection of External Components External components and its value required for R1276S are described. Each value is reference value at initial. Since inductor’s variations and output capacitor’s effective value may lead a drift of phase characteristics, adjustment to a unity-gain and phase characteristics may be required by evaluation on the actual unit. 1. Determination of Requirements Determine the frequency, the output capacitor, the current and the input voltage required. For reference values, parameters listed in the following table will be used to explain each equation Parameter Value Output Voltage (VOUT) 3.3 V Output Current (IOUT) 3 A Input Voltage (VIN) 12 V Input Voltage Range 8 V to 16 V Frequency (fOSC) 1000 kHz ESR of Output Capacitor (RCOUT_ESR) 3 mΩ 2. Selection of Unity-gain Frequency (f UNITY) The unity-gain frequency (fUNITY) is determined by the frequency that the loop gain becomes “1” (zero dB). It is recommended to select within the range of one- sixth to one-twentieth of the oscillator frequency (f OSC). Since the fUNITY determines the transient response, the higher the f UNITY, the faster response is achieved, but the phase margin will be tight. Therefore, it is required that the f UNITY can secure the adequate stability. As for the reference, the fUNITY is set to 100 kHz.

No. EY-404-201112 3. Selection of Inductor After the input and the output voltages are determined, a ripple current ( ∆IL) for the inductor current is determined by an inductance (L) and an oscillator frequency (f OSC). The ripple current (∆IL) can be calculated by Equation 1. VIN_MAX : Maximum input voltage The core loss in the inductor and the ripple current of the output voltage become small when the ripple current (∆IL) is small. But, a large inductance is required as shown by Equation 1. The inductance can be calculated by Equation 2 when a reference value of ∆IL assumes 0.6 A is appropriate value. = (VOUT / 0.6 / fOSC) x (1-VOUT / VIN_MAX) The inductance can be calculated by substituting each parameter to Equation 2. = 4.37 µH When selecting the inductor of 4.7 µH as an approximate value of the above calculated value, ∆ I L can be shown as below. = 0.557 A 4. Setting of Output Capacitance The output capacitance (COUT) must be set to meet the following conditions. ■ Calculation based on phase margin To secure the adequate stability, it is recommended that the pole frequency (f P_OUT) is set to become equal or below one-fourteenth of the unity-gain frequency. The pole frequency (fP_OUT) can be calculated by Equation 3. fP_OUT = 1/(2 x π x COUT_EFF x ((ROUT_MIN x 2 x π x f OSC x L) / (ROUT_MIN + 2 x π x fOSC x L) + RCOUT_ESR)) COUT_EFF : Output capacitance (effective value) ROUT_MIN : Output resistance at maximum output current ROUT_MIN = VOUT/ IOUT = 3.3 V / 3 A = 1.1 Ω

No. EY-404-201112 Equation (4) can be expressed by substituting fP_OUT = fUNITY / 14 to Equation 3. COUT_EFF = 14 / (2 ×π× fUNITY × ((ROUT_MIN × 2 ×π× fOSC × L) / (ROUT_MIN + 2 ×π× fOSC × L) + RCOUT_ESR)) Then, the output capacitance (effective value) can be calculated by substituting each parameter to Equation 4. COUT_EFF =14/(2 ×π×100kHz×((1.1Ω × 2 ×π× 1000 kHz × 4.7 µH)/(1.1Ω+ 2 ×π× 1000kHz × 4.7µH)+3mΩ)) = 21.01 µF ■ Calculation based on ripple at PWM mode With using the calculated value of C OUT, the amount of ripple at the PWM mode can be shown as E quation 5 and Equation 6. IL_PWM : Maximum current of inductor VOUT_PWM : Maximum output ripple Ripple at the PWM mode must be set to become 10 mV to 15 mV or less. If it is over the target value, the output capacitance must be calculated by Equation 7. Then, the output capacitance (effective value) can be calculated by substituting each parameter to Equation 7. COUT_EFF = 0.557 A / 2 / 1000 kHz / (10 mV – 3mΩ ×0.557 A) = 33.46 uF It is recommended that the output capacitance is set to become equal or over the effective value calculated by Equation 4 and Equation7. The ou tput capacitance (effective value), which is derated depending on the DC voltage applied, can be calculated by Equation 8. Refer to “Capacitor Manufacture’s Datasheet” for details about derating. COUT_SET : Output capacitor’s spec VCO_AB : Capacitor’s voltage rating

No. EY-404-201112 With using Equation 8, the effective value is calculated to become 33.46 µF or more. The output voltage (COUT) can be shown as below when VCO_AB is 16 V. COUT_SET > COUT_EFF / ((VCO_AB - VOUT) / VCO_AB) COUT > 42.15 µF As the calculated result, COUT selects a capacitor of 44 µF (22 µF × 2) (the effective value is 34.9 µF). ■ Calculation based on ripple at VFM mode With using the calculated value of C OUT, the amount of ripple at the VFM mode can be shown as E quation 9 and Equation 10. IL_VFM : Maximum current of inductor COEF_TON_VFM : ON-time scaling (multiples of PWM_ON time) VOUT_VFM : Maximum output ripple COEF_TON_VFM can be calculated by 1.75 times (Typ.) as the design value. The ripple value can be calculated by substituting each parameter to Equation 9 and Equation 10. IL_VFM = ((16 V - 3.3 V) / 4.7 µH) × 1.75 × 3.3 V / 16 V / 1000 kHz = 0.975 A VOUT_VFM = 3 mΩ × 0.975 A + 1.75 × (0.975 A / 2) / 1000 kHz / 34.9 µF = 27.36 mV VOUT_VFM must be set to become the target ripple value or less. If VOUT_VFM is over the target value, the output capacitance must be calculated by Equation 11.

No. EY-404-201112 5. Designation of Phase Compensation Since the current amplifier for the voltage feedback is output via the COMP pin, the phase compensation is achieved with using external components. The phase compensation is able to secure stable operation with using a ceramic output capacitor and the phase compensation circuit. RBOT RTOP CC2CC RC CSPD VREF 0.64V VOUT COMP ERROR_AMP VFB Connection Example for External Phase Compensation Circuit ■ Calculation of RC The phase compensation resistance (R C) to set the calculated unity -gain frequency can be calculated by Equation 12. gm_ea : Error amplifier of gm VREF : Reference voltage (0.64 V) gm_pwr : power level of gm gm_pwr × ∆VS = ∆IL gm_ea / ∆VS = 0.05 × 10 ^ (-6) × fOSC / VOUT ∆VS : Output amplitude of the slope circuit RC can be calculated by substituting Equation 13 to Equation 12. RC = 2 ×π×fUNITY × VOUT × COUT_EFF / (VREF × 0.05 × 10 ^ (-6) × ∆IL × fOSC / VOUT) =13.4 ≒12 kΩ

No. EY-404-201112 ■ Calculation of CC CC must be calculated by Equation 14 so that the zero frequency of the error amplifier meets the highest pole frequency (fP_OUT). Then, fP_OUT = 4.28 kHz is determined by calculation of Equation 3. = 2.772 ≒ 3.3 nF ■ Calculation of CC2 CC2 can be calculated by two different calculation methods to vary from the zero frequency (f Z_ESR) depending on the ESR of a capacitor. f Z_ESR can be calculated by Equation 15. = 1519 kHz [When the zero frequency is lower than fOSC / 2] CC2 sets the pole to fZ_ESR. [When the zero frequency is higher than fOSC / 2] CC2 sets the pole to fOSC / 2 so as to be a noise filter for the COMP pin. fOSC / 2 = 1 / (2 ×π× RC × CC2） In the reference example, CC2 is used as the noise filter for the COMP pin because of being higher than fOSC/2. CC2 = 26.53 ≒ 22 pF ■ Calculation of CSPD CSPD is set to the zero frequency to meet the unity-gain frequency. R TOP = RBOT × (VOUT / VREF -1) When RBOT = 39 kΩ, RTOP = 39 kΩ × (3.3 V / 0.64 V -1) = 162.1 k Ω C SPD = 1 / (2 ×π× 100 kHz × 162.1 kΩ) = 9.82 ≒ 10 pF

No. EY-404-201112 Cautions in Selecting External Components Inductor

Choose an inductor that has small DC resistance, sufficient allowable current and is hard to cause magnetic saturation. DC resistance affects efficiency. If the allowable current is insufficient and magnetic saturation occurs, the current cannot be superimposed and the inductor may be destroyed. If the inductance value is small, the peak current of LX may increase along with the load current. As a result, the current limit circuit may start to operate when the peak current of LX reaches to “LX limit current”. Capacitor
Choose a capacitor that has a sufficient margin to the drive voltage ratings with consideration of the DC bias characteristics and the temperature characteristics.
T he use of ceramic capacitors for C IN and COUT is recommended although an electrolytic capacitor can be used. If using the electrolyte capacitor, select it with the lowest possible ESR with consideration of the allowable ripple current rating (IRMS). IRMS can be calculated by the following equation. IRMS ≒ I OUT/ VIN × √{ VOUT × (VIN – VOUT) } Electrolytic capacitors may have characteristics that ESR increases at low temperatures, use it with caution to the phase compensation, especially when using as a C OUT.

No. EY-404-201112 THEORY OF OPERATION MODE Pin Function The R1276S operating mode is switched between the forced PWM mode and PLL_PWM mode, by a voltage or a pulse applied to MODE pin. The forced PWM mode is selected when the voltage of the MODE pin is 1.4 V or more, and the PWM works regardless of a load current. The PWM/VFM auto-switching mode is selected when it is 0.74 V or less, and control is switched between a PWM mode and a VFM mode depending on the load current. See “Forced PWM mode and VFM mode” for details. And see “Frequency Synchronization Function” for the operation on connecting an external clock. Frequency Synchronization Function The R1276S can synchronize to the external clock being inputted via the MODE pin, with using a PLL (Phase- locked loop). The forced PWM mode is selected during synchronization. The external clock with a pulse-width of 100 ns or more is recommended. The allowable range of oscillation frequency is 0.5 to 1.5 times of the set frequency, and the operating guaranteed frequency is in the 250 kHz to 1 MHz range(1). When starting up the device while the external clock is sent to the MODE pin, the device synchronizes to the external clock while starting up with soft-start. Be aware that if the voltage difference between input and output is reduced and the device goes into the maxduty or duty-over condition, the device starts operating at 1 to1/4 of the synchronous frequency and goes into the asynchronous condition with the MODE pin. Duty-over When the input voltage is reduced at cranking, the operating frequency is reduced until one-fourth of the set frequency with being linearly proportional to time in order to maintain the output voltage. Exploiting the ON duty to exceed the maxduty value at normal operation can make the differential between input and output voltages small. The duty over function operates when the minimum OFF time is detected at the set frequency and external synchronization frequency UVLO (Undervoltage Lockout) If the VCC pin voltage drops below the UVLO detection threshold of 3.3 V (Typ.) due to the input voltage drop, the R1276S turns the switching off to prevent the malfunction of the device. Due to the switching stop, the output voltage drops according to the load and C OUT. If the VCC pin voltage rises above the UVLO threshold of 4.3 V (Typ.), the device restarts the operation with soft-start. For the R1276S, 4.5 V, the maximum UVLO release voltage, is a start-up voltage. OVLO (Overvoltage Lockout) If the input voltage rises above the OVLO detection threshold of 35 V (Typ.), the R1276S turns the switching off to prevent malfunctions of the device or damage on the transistor due to overvoltage. Due to the switching stop, the output voltage drops according to the load and C OUT values. If the input voltage drops below the OVLO release threshold of 34 V (Typ.), the device restarts the operation with soft-start. Note that this function does not guarantee the operation above the absolute maximum ratings. (1) The adjustable oscillation frequency range becomes 250 kHz ≤ fOSC ≤ 600 kHz when 0.7 V ≤ VOUT < 3.3 V.

No. EY-404-201112 PGOOD (Power Good) Output The power good function with using a NMOS open drain output pin can detect the following states of the R1276S. The NMOS turns on and the PGOOD pin becomes “Low” when detecting them. After the device returns to their original state, the NMOS turns off and the PGOOD pin outputs “H igh” (PGOOD Input Voltage: VUP). ・CE = “Low” (Shut down) ・UVLO ・OVLO ・Thermal Shutdown ・Soft-start ・UVD ・OVD ・Hiccup-type Protection The PGOOD pin is designed to become 0.25 V or less in “Low” level when the current floating to the PGOOD pin is 1 mA. The use of the PGOOD input voltage (VUP) of 5.5 V or less and the pull-up resistor (RPG) of 10 kΩ to 100 kΩ are recommended. If not using the PGOOD pin, connect it to “Open” or “GND”. PGOOD “H” is detected under abnormal condition. VUP VPGOOD RPG Power Good Circuit

No. EY-404-201112 CE VFB 0.64V PGOOD 120us (Typ.) VIN 1.1V Hi-z Hi-z time time time time Rising / Falling Sequence of Power Good Circuit

No. EY-404-201112 Under Voltage Detection (UVD) The UVD function indirectly monitors the output voltage with using the FB pin. The PGOOD pin outputs “Low” when the UVD detector threshold is 90% (Typ.) of V FB and VFB is less than the UVD detector threshold for more than 15 µs (Typ.). When VFB is over 93% (Typ.) of 0.64 V, the PGOOD pin outputs “High” after delay time (Typ.120 µs.). And, the hiccup-type overcurrent protection works when detecting a current limiting during the UVD detection. Overvoltage Detection (OVD) The OVD function indirectly monitors the output voltage with using the FB pin. Switching stops even if the internal circuit is active state, when detecting the overvoltage of VFB. The PGOOD pin outputs “Low” when the OVD detector threshold is 110% (Typ.) of VFB and VFB is over the OVD detector threshold for more than 15 µs Then, switching is controlled by normal operation. Hiccup-type Overcurrent Protection The hiccup-type overcurrent protection can work under the operating conditions that is the UVD can function during the current limiting. The hiccup type protection stops switching and releases the circuit after the protection delay time (Typ. 7.5 ms). Since this protection is auto-release, the CE pin switching of “Low”/“High” is unnecessary. When the output is shorted to GND, switching of “ON” / “OFF” is repeated until the shorting is released. Minimum ON-Time The minimum ON-time means the minimum time duration that the R1276S can turn the high-side transistor on during the oscillation period. The minimum on- time of the device (Typ. 70 ns) is determined by the internal circuit. The dev ice cannot generate a pulse width that is less than the pulse width of minimum on- time. Therefore, when setting the output voltage and the oscillator frequency, be careful that the minimum step-down ratio [VOUT / VIN x (1 / fOSC)] is not less than the minimum on-time. If they are set to less than the minimum step- down ratio, the pulse skipping occurs, which outputs the VOUT but increases the ripple current and the output voltage ripple. Minimum OFF-Time The minimum OFF-time means the minimum time duration that the R1276S can turn the high- side transistor off during the oscillation period. By the adoption of bootstrap method, the high- side transistor, which is used as the R1276S inter nal circuit for the minimum off -time, is used a N MOS. The voltage sufficient to drive the high-side transistor must be charged. Therefore, the minimum off-time is determined from the required time to charge the voltage. By the adoption of the frequency’s reduction method by one- quarter of a set value (Min.), if the input-output difference voltage becomes small or load transients are caused, the OFF period can be caused once in four -cycle period of normal cycle. As a result, the minim um off-time becomes 120 ns (Typ.) substantially, and the maximum duty cycle can be improved.

No. EY-404-201112 Current Limit The output current of the R1276S is limited by the current limit using a peak current method. The current limit is set to 4.2 A (Typ. DC value) and it is fixed inside the IC. The current limit circuit limits the current by monitoring the drain to source voltage of a high- side transistor. The transitional current limit of the inductor current is set to be higher than the DC value. The current limit of the device starts operating after the minimum on-time, so it has to be careful especially when the device is used close to the minimum on-time because the current limit will increase. The following diagram shows the relation between current limit and on-t ime using our evaluation board. The longer th e on-time is, the more the current approaches t he current limit value of 4.2 A (Typ. DC value). R1276S Current Limit vs LX On-Time 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 70 80 90 100 110 120 130 140 ILIM (A) ON Time(ns)

No. EY-404-201112 Precautions for Operating in Low Input Voltage When using the R1276S with VIN = 5 V or less, the load current may be limited in following two cases. First Case: The device designed to reach current limit by monitoring the voltage difference between VIN and LX. During the low input voltage operation, the driving capability of high- side transistor decreases, so the voltage difference between VIN and LX becomes larger with smaller output current. Therefore, the load current may be limited during the low input voltage operation. Second Case: During the low input voltage operation, the duty-over function decreases the oscillator frequency. While the oscillator frequency is 1/4 of the set frequency, drawing the load current can cause a voltage difference between the input and output. These make the device to exit from duty -over condition, and as a result, the output voltage drops. Both cases show that the current limit is depending on the input voltage and load current. Careful consideration is required when applying a heavy load while the input voltage is low. The following graph shows the relation between input voltage and load current. If the BST voltage between BST and LX drops extremely, the device forcibly turns off the switching to charge the BST voltage to prevent malfunction of the logic circuit driven by BST voltage. This may occur when V IN is 4.5 V or less and it may affect the output voltage ripple. Also, if VIN is less than 4.5 V and UVD is detected as the output voltage decreases, the hiccup-type overcurrent protection may work due to the protection function inside the IC. VOUT = 3.3 V / fOSC = 1MHz Setting R1276S Output Current vs Input Voltage 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.0 4.0 5.0 6.0 IOUT (A) VIN (V) Ta=25°C

No. EY-404-201112 Output Voltage Setting The output voltage (V OUT) can be set by adjustable values of R TOP and R BOT. The value of V OUT can be calculated by Equation 1: For example, when setting VOUT = 3.3 V and setting RBOT = 39 kΩ, RTOP can be calculated by substituting them to Equation 1. As a result of the Equation 2, RTOP can be set to 162 kΩ. To make 162 kΩ with using the E24 type resistors, the connecting use of 160 k Ω and 2 kΩ resistors in series is required. If the tolerance level of the set output voltage is wide, using a resistor of 160 kΩ to RTOP can reduce the number of components. Rbot is recommended to be 39kΩ or less. RTOP = (3.3 V / 0.64 V - 1) × 39 kΩ R1276S is designed assuming RTOP and RBOT resistance variation of ± 1% Oscillation Frequency Setting Connecting the oscillation frequency setting resistor (R RT) between the RT pin and GND can control the oscillation frequency in the range of 250 kHz to 1 MHz(1). For example, using the resistor of 60 kΩ can set the frequency of about 500 kHz. The Electrical Characteristics guarantees the oscillation frequency under the conditions stated below for f OSC0 at RRT = 121 kΩ and fOSC1 at RRT = 29 kΩ. For the SSCG type (xxxC), an up-spreading modulation is used (Typ. +10%). RRT [kΩ] = 34610 × fOSC [kHz] ^ (-1.023) R1276S Oscillation Frequency vs. Oscillation Frequency Setting Resistor (1) The adjustable oscillation frequency range becomes 250 kHz ≤ fOSC ≤ 600 kHz when 0.7 V ≤ VOUT < 3.3 V. 200 400 600 800 1000 1200 fosc[kHz] RRT[kΩ]

No. EY-404-201112 Soft-start Adjustment The soft-start time is a time between a rising edge (“High” level) of the CE pin and the timing when the output voltage reaches the set output voltage. Connecting a capacitor (C SS) to the CSS/TRK pin can adjust the soft- start time (tSS) – provided the internal soft-start time of 500 µs (Typ.) as a lower limit. The adjustable soft-start time (tSS2) is 1.6 ms (Typ.) when connecting an external capacitor of 4.7 nF with the charging current of 2.0 μA (Typ.) and 0.64 V (Typ.). If not required to adjust the soft-start time, set the CSS/TRK pin to “Open” to enable the internal soft-start time (tSS1) of 500 µs (Typ.). When a large-capacitance output capacitor is connected, the overcurrent protection may work due to an inflow of large current at startup. Thus, set a longer soft start time to reduce the amount of current and prevent from operating the protections due to the rapid startup. R1276 may repeatedly restart by detecting an overcurrent at startup depending on conditions, set t SS to 4 ms or more. Each of soft -start time (tss1/ tss2) when CSS/TRK pin is set to “Open” is guaranteed under the conditions described in the chapter of “Electrical Characteristics”. 1nF 3.3nF 10nF 33nF CSS tSS 10ms 3.3ms 1.2ms 0.5ms 1.6ms 4.7nF Soft-start Time Adjustment Capacitor vs Soft-start Time CE VOUT VSET tSS tVO_S PGOOD 120us (Typ.) 1.27V time time time Soft-start Sequence CSS [nF] = (tSS – tVO_S) / 0.64 × 2.0 tSS: Soft-start time (ms) tVO_S: Time period from CE = “High” to VOUT’s rising (Typ. 0.160 ms)

No. EY-404-201112 Tracking Function Applying an external tracking voltage to the CSS/TRK pin can control the soft -start sequence – provided that the lowest internal soft -start time is limited to 500 µs (Typ.). Since V FB becomes nearly equal to V CSS/TRK at tracking, the complex start timing and soft -start can be easily designed. The available voltage at tracking is between 0 V and 0.64 V . If the tracking voltage is over 0.64 V, the internal reference voltage of 0.64 V is enabled. Also, an arbitrary falling waveform can be generated by reducing VCSS/TRK to 0.64 V (Typ.) or less, because the R1276S supports both of up- and down- tracking. CSS/TRK VOUT 0.64V SS Normal Operation SS Tracking Sequence Reverse Current Limit The reverse current limit start s operating when the reverse current flowing through the low -side transistor exceeds the set reverse current threshold. It turns off the low-side transistor to control the reverse current. The reverse current limit is 1.7 A (Typ.). This function operates when the output voltage is pulled up more than the set output voltage due to short-circuiting. SSCG (Spread Spectrum Clock Generator) The SSCG function works for EMI reduction at the PWM mode. The function makes EMI waveforms decrease in amplitude to generate a triangle waveform within approximately +10.0% (Typ.) of the oscillator frequency (fOSC). The modulation cycle is f OSC / 128. SSCG is enabled only when MODE = High. SSCG is not effective when a clock is externally applied. The oscillator frequencies are not modulated during the soft -start and operates at the set frequency or external sync frequency.

No. EY-404-201112 Bad Frequency Protection (BADFREQ) If a current equivalent to 4 MHz (Typ.) or more or 125 kHz (Typ.) or less is appl ied to the RT pin when the oscillator frequency setting resistor (R RT) of the RT pin is in open / short, the R1276S will stop switching to protect the IC and will cause the internal state to transition to its state before the soft-start. The R1276S will restart under the normal control from the state of soft-start when recover after the abnormal condition. LX PGOOD time time VFB 0.64V time BADFEQ Detection BADFEQ Release BADFREQ Detection/ Release Sequence

No. EY-404-201112 Operation of Step-down DC/DC Converter The basic operation of the step-down DC/DC converter is shown in the following figures. This step-down DC/DC converter charges energy in the inductor while the high-side transistor turns on, and discharges the energy from the inductor when the high-side transistor turns off. This inductor r educes the energy loss to provide the lower output voltage (VOUT) than the input voltage (VIN). VIN High Side Tr. Low Side Tr. VOUT COUT L IOUT Basic Circuit Current Through Inductor Step1. When the high-side transistor turns on, current IL (= i1) flows through the L to charge COUT and provide IOUT. At this moment, IL = i1 increases from ILMIN of 0 to reach ILMAX in proportion to the on-time period (tONHS) of the high-side transistor. Step2. When the high-side transistor turns off, the low-side transistor turns on in order to maintain IL at ILMAX, and current IL (= i2) flows. Step3. When MODE = L (VFM/PWM Auto-switching mode), I L (= i2) decreases gradually and reaches IL = ILMIN = 0, the low-side transistor turns off. This case is called as discontinuous mode. The VFM mode is switched when R1276S goes to the discontinuous mode. If the output current is increased, a time period of t OFFHS runs out prior to reach of I L = ILMIN = 0. The result is that the high- side transistor turns on and the low -side transistor turns off in the next cycle. This case is called continuous mode. When MODE = H (Forced PWM mode), MODE = External Clock (PLL_PWM mode), Since the continuous mode works at all time, the low -side transistor turns on until going to the next cycle. That is, the low-side transistor must keep “On” to meet IL = ILMIN < 0, when reaches IL = ILMIN = In the PWM mode, the output voltage is maintained constant by controlling tONHS with the constant switching frequency (fOSC). tONHS tOFFHS ILMIN ILMAX IL i1 i2

No. EY-404-201112 Forced PWM Mode and VFM Mode The output voltage control methods are selectable between the PWM / VFM Auto- switching mode and the forced PWM mode by using the MODE pin. Forced PWM Mode The R1276S goes into the forced PWM mode by setting the MODE pin “High”. The forced PWM mode operates at fixed switching frequency even during the light load in order to reduce noise. Therefore, when the output current (IOUT) is ∆IL / 2 or less, ILMIN becomes "0” or less. That is, the electric charge, which is charged to C OUT, is discharged via transistor for the durations – when IL reaches “0” from ILMIN during the tONHS periods and when IL reaches ILMIN from “0” during tOFFHS periods. But, pulses are skipped to prevent the overvoltage when high- side transistor is set to ON under the condition that the output voltage being more than the set output voltage. VFM Mode PWM / VFM Auto -switching mode is selected when setting the MODE pin to “Low”. This mode can automatically switch from PWM to VFM to achieve a high-e fficiency during light load conditions. By the VFM mode architecture, the high- side transistor is turned on for t ONHS × 1.75 (typ.) at the PWM mode under the same condition as the VFM mode when the FB pin voltage drops below the internal reference voltage (Typ.0.64 V). After the On-time, the high-side transistor is turned off and the low -side transistor is turned on. When the inductor current of 0 A is detected, the low-side transistor is turned off and the switching operation is stopped (Both of hi - and lo w-side transistors are OFF). The switching operation restarts when the FB pin voltage becomes less than 0.64 V. The On-time at the PWM mode is determined by a resistance, input and output voltages, which are connected to the RT pin. Refer to “Calculation of VFM Ripple” for detailed description on the On-time at the VFM mode. ILMAX ILMIN tONHS tOFFHS T=1/fOSC IL IOUT t ΔIL ILMAX ILMIN tONHS tOFFHS IL t Forced PWM Mode VFM Mode

No. EY-404-201112 Calculation of VFM Ripple Calculation example of output ripple voltage ( VOUT_VFM) is described. VOUT_VFM can be calculated by Equation 1. And, the maximum value of inductor current (IL_VFM) can be calculated by Equation 2. VOUT_VFM : Output ripple RCOUT_ESR : ESR of output capacitor IL_VFM : Maximum current of inductor COEF_TON_VFM : Scaling factor of On-time - Typ.1.75 times (Design value) (VIN-VOUT) / L : Slope of inductor current COEF_TON_VFM × VOUT / VIN / fOSC : On-time Inductor Current Waveform at VFM Mode IL (A) Time(s) Slope ⊿IL=(VIN-VOUT)/L Slope ⊿IL= VOUT/L Inductor Current (Max.) IL_VFM Average Area of I L (A) x Time (s) High Side Tr. Low Side Tr.

No. EY-404-201112 Output voltage can be calculated by the following simple equation. VOUT = I × T/C I : Current, C : Capacitance, T : Time Since I is represented by 1/2 x IL_VFM as the average current, the time of current passing at the VFM mode can be expressed by the following equation. T = COEF_TON_VFM / fOSC And, the output ripple voltage (V OUT_VFM) is superimposed a voltage for ESR × I, and Equation 1 is determined. But, ESR is so small that it may be ignored if ceramic capacitors are connected in parallel. The amount of charge to the output capacitor can be calculated by Equation 3. (High-side transistor On-time (T1) + Low-side transistor On-time (T2)) × Average amount of current Then, T1 and T2 can be calculated by the following equations, and the time of current passing can be determined. T1 = C OEF_TON_VFM / fOSC × VOUT / VIN ····· (On-time at VFM) T2 = (VIN/VOUT-1) × T1 (0 = IL_VFM – VOUT/L × T2) T = T1 + T2 = VIN /VOUT × T1 = COEF_TON_VFM / fOSC And then, the amount of charge can be determine as Equation 4. With using above equations, the output ripple voltage (VOUT_VFM) can be calculated by Equation 5.

No. EY-404-201112 TECHNICAL NOTES The performance of a power source circuit using this device is highly dependent on a peripheral circuit. A peripheral component or the device mounted on PCB should not exceed a rated voltage, a rated current or a rated power. When designing a peripheral circuit, please be fully aware of the following points. Refer to PCB Layout below.

External components must be connected as close as possible to the ICs and make wiring as short as possible. Especially, the capacitor connected in between VIN pin and GND pin must be wiring the shortest. If their impedance is high, internal voltage of the IC may shift by the switching current, and t he operating may be unstable. Make the power supply and GND lines sufficient.
Place a capacitor ( CBST) as close as possible to the LX pin and the BST pin. If controlling slew rate for EMI, a resistor (RBST) should be in series between the BST pin and the capacitor (CBST).
The tab on the bottom of the HSOP-18 package must be connected to GND when mounted on the board. To improve thermal dissipation on the multilayer board, secure the GND layer as large as possible and set via to release the heat to the other layer in the connecting part of the tab on the bottom.
The NC pin must be set to “Open”.
The MODE pin requires the high voltages with the high stability when the forced PWM mode (MODE = “High”) is enabled. If the voltage with the high stability cannot be applied, connection to the VCC pin as “High” level is recommended. Avoid the use of the MODE pin being “Open”.
If V OUT is a minus potential, the setup cannot occur.
Shorten the wiring between the Lx pin and the inductor so that the parasitic capacitance is not provided.
It is recommended to place the input capacitor (CIN) on the same side as the IC. If it is placed on the different side as the IC by using via, the noise may be increased due to the parasitic inductance component of via.
Feedback the output voltage near the COUT.
Place RTOP, RBOT, and CSPD near FB pin and mount them at a position apart from the inductor, Lx pin, and BST pin to prevent the effect of noise.

No. EY-404-201112 PCB Layout R1276S Layer 1 (Top) Layer 2 Layer 3 Layer 4 (Bottom)

No. EY-404-201112 TYPICAL CHARACTERISTICS Note: Typical Characteristics are intended to be used as reference data; they are not guaranteed. 1) FB Voltage 2) Oscillator Frequency 250 kHz (RT = 121 kΩ) 1000 kHz (RT = 28.7 kΩ) 3) Soft-start Time Internally Fixed Soft-start Time (CSS = Open) Externally Adjustable Soft-start Time (CSS = 4.7 nF) 0.62 0.63 0.63 0.64 0.65 0.65 0.66 -40 -20 0 20 40 60 80 100 120 VFB [V] Tempreture [℃] 225 230 235 240 245 250 255 260 265 270 275 -40 -20 0 20 40 60 80 100 120 FOSC0 [kHz] Tempreture [℃] 900 920 940 960 980 1000 1020 1040 1060 1080 1100 -40 -20 0 20 40 60 80 100 120 FOSC1 [kHz] Tempreture [℃] 0.40 0.45 0.50 0.55 0.60 -40 -20 0 20 40 60 80 100 120 TSS1 [ms] Tempreture [℃] 1.2 1.3 1.4 1.5 1.6 1.7 1.8 -40 -20 0 20 40 60 80 100 120 TSS2 [ms] Tempreture [℃] Temperature [ °C ] Temperature [ °C ] Temperature [ °C ] Temperature [ °C ] Temperature [ °C ]

No. EY-404-201112 4) LX Limit Current 5) VIN Supply Current 1 VIN = 12 V, Mode = L VIN = 12 V, Mode = H 6) UVLO -40 -20 0 20 40 60 80 100 120 IVIN0 [μA] Tempreture [℃] 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 -40 -20 0 20 40 60 80 100 120 IVIN1 [mA] Tempreture [℃] 3.0 3.5 4.0 4.5 -40 -20 0 20 40 60 80 100 120 VUVLO [V] Tempreture [℃] VUVLO1 (VCC Falling) VUVLO2 (VCC Rising) Temperature [ °C ] Temperature [ °C ] Temperature [ °C ] Temperature [ °C ]

No. EY-404-201112 7) CE Input Voltage 8) Efficiency VOUT = 3.3 V, fOSC = 250 kHz VOUT = 3.3 V, fOSC = 500 kHz VOUT = 3.3 V, fOSC = 1000 kHz 1.10 1.15 1.20 1.25 -40 -20 0 20 40 60 80 100 120 VCE [V] Tempreture [℃] CE ”Low” Input Voltage VCEL CE ”High” Input Voltage VCEH 100 0.01 0.1 1 10 100 1000 10000 Efficiency [%] Output Current IOUT [mA] Vin=8V Vin=12V Vin=16V Vin=24V Mode = L Mode = H 100 0.01 0.1 1 10 100 1000 10000 Efficiency [%] Output Current IOUT [mA] Vin=8V Vin=12V Vin=16V Vin=24V Mode = H Mode = L 100 0.01 0.1 1 10 100 1000 10000 Efficiency [%] Output Current IOUT [mA] Vin=8V Vin=12V Vin=16V Vin=24V Mode = L Mode = H Temperature [ °C ]

No. EY-404-201112 VOUT = 5.0 V, fOSC = 250 kHz VOUT = 5.0 V, fOSC = 500 kHz VOUT = 5.0 V, fOSC = 1000 kHz VOUT = 6.5 V, fOSC = 250 kHz VOUT = 6.5 V, fOSC = 500 kHz 100 0.01 0.1 1 10 100 1000 10000 Efficiency [%] Output Current IOUT [mA] Vin=8V Vin=12V Vin=16V Vin=24V Mode = H Mode = L 100 0.01 0.1 1 10 100 1000 10000 Efficiency [%] Output Current IOUT [mA] Vin=8V Vin=12V Vin=16V Vin=24V Mode = L Mode = H 100 0.01 0.1 1 10 100 1000 10000 Efficiency [%] Output Current IOUT [mA] Vin=8V Vin=12V Vin=16V Vin=24V Mode = H Mode = L 100 0.01 0.1 1 10 100 1000 10000 Efficiency [%] Output Current IOUT [mA] Vin=12V Vin=16V Vin=24V Mode = H Mode = L 100 0.01 0.1 1 10 100 1000 10000 Efficiency [%] Output Current IOUT [mA] Vin=12V Vin=16V Vin=24V Mode = H Mode = L

No. EY-404-201112 VOUT = 6.5 V, fOSC = 1000 kHz 9) Load Transient Response VOUT = 3.3 V, VIN = 12 V, fOSC = 500 kHz VOUT = 3.3 V, VIN = 1 2 V, fOSC = 500 kHz IOUT = 0.1 A → 1 A, Mode = L, Tr = 1 A/μs IOUT = 1 A → 0.1 A, Mode = L, Tf = 1 A/μs VOUT = 3.3 V, VIN = 12 V, fOSC = 500 kHz VOUT = 3.3 V, VIN = 12 V, fOSC = 500 kHz IOUT = 0 A → 3 A, Mode = L, Tr = 1 A/μs IOUT = 3 A → 0 A, Mode = L, Tf = 1 A/μs 100 0.01 0.1 1 10 100 1000 10000 Efficiency [%] Output Current IOUT [mA] Vin=12V Vin=16V Vin=24V Mode = H Mode = L 0.0 1.0 2.0 3.0 4.0 3.0 3.1 3.2 3.3 3.4 3.5 3.6 300 400 500 600 700 800 900 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 3.0 3.1 3.2 3.3 3.4 3.5 3.6 300 400 500 600 700 800 900 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 3.1 3.2 3.3 3.4 3.5 3.6 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 3.1 3.2 3.3 3.4 3.5 3.6 50 150 250 350 450 550 Output Current VOUT [A] Output Voltage VOUT [V] Time [ms] Vout Iout

No. EY-404-201112 VOUT = 3.3 V, VIN = 12 V, fOSC = 500 kHz VOUT = 3.3 V, VIN = 12 V, fOSC = 500 kHz IOUT = 0.1 A → 1 A, Mode = L, Tr = 1 A/μs IOUT = 1A → 0.1A, Mode = H, Tf = 1 A/μs VOUT = 3.3 V, VIN = 12 V, fOSC = 500 kHz VOUT = 3.3 V, VIN = 12 V, fOSC = 500 kHz IOUT = 0 A → 3 A, Mode = H, Tr = 1 A/μs IOUT = 3 A → 0 A, Mode = H, Tf = 1 A/μs VOUT = 5.0 V, VIN = 12 V, fOSC = 500 kHz VOUT = 5.0 V, VIN = 12 V, fOSC = 500 kHz IOUT = 0.1 A → 1 A, Mode = L, Tr = 1 A/μs IOUT = 1 A → 0.1 A, Mode = L, Tf = 1 A/μs 0.0 1.0 2.0 3.0 4.0 3.0 3.1 3.2 3.3 3.4 3.5 3.6 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 3.0 3.1 3.2 3.3 3.4 3.5 3.6 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 3.0 3.1 3.2 3.3 3.4 3.5 3.6 100 200 300 400 500 600 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 3.0 3.1 3.2 3.3 3.4 3.5 3.6 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 4.7 4.8 4.9 5.0 5.1 5.2 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 4.7 4.8 4.9 5.0 5.1 5.2 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout

No. EY-404-201112 VOUT = 5.0 V, VIN = 12 V, fOSC = 500 kHz VOUT = 5.0 V, VIN = 12 V, fOSC = 500 kHz IOUT = 0 A → 3 A, Mode = L, Tr = 1 A/μs IOUT = 3 A → 0 A, Mode = L, Tf = 1 A/μs VOUT = 5.0 V, VIN = 12 V, fOSC = 500 kHz VOUT = 5.0 V, VIN = 12 V, fOSC = 500 kHz IOUT = 0.1 A → 1 A, Mode = H, Tr = 1 A/μs IOUT = 1 A → 0.1 A, Mode = H, Tf = 1 A/μs VOUT = 5.0 V, VIN = 12 V, fOSC = 500 kHz VOUT = 5.0 V, VIN = 12 V, fOSC = 500 kHz IOUT = 0 A → 3 A, Mode = H, Tr = 1 A/μs IOUT = 3 A → 0 A, Mode = H, Tf = 1 A/μs 4.7 4.8 4.9 5.0 5.1 5.2 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0 4.7 4.8 4.9 5.0 5.1 5.2 50 150 250 350 450 550 Output Current IOUT [A] Output Voltage VOUT [V] Time [ms] Vout Iout 0.0 1.0 2.0 3.0 4.0 4.7 4.8 4.9 5.0 5.1 5.2 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 4.7 4.8 4.9 5.0 5.1 5.2 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 4.7 4.8 4.9 5.0 5.1 5.2 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 4.7 4.8 4.9 5.0 5.1 5.2 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout

No. EY-404-201112 VOUT = 6.5 V, VIN = 12 V, fOSC = 500 kHz VOUT = 6.5 V, VIN = 12 V, fOSC = 500 kHz IOUT = 0.1 A → 1 A, Mode = L, Tr = 1 A/μs IOUT = 1 A → 0.1 A, Mode = L, Tf = 1 A/μs VOUT = 6.5 V, VIN = 12 V, fOSC = 500 kHz VOUT = 6.5 V, VIN = 12 V, fOSC = 500 kHz IOUT = 0 A → 3 A, Mode = L, Tr = 1 A/μs IOUT = 3 A → 0 A, Mode = L, Tf = 1 A/μs VOUT = 6.5 V, VIN = 12 V, fOSC = 500kHz VOUT = 6.5 V, VIN = 12 V, fOSC = 500kHz IOUT = 0.1 A → 1 A, Mode = H, Tr = 1 A/μs IOUT = 1 A → 0.1 A, Mode = H, Tf = 1 A/μs 0.0 1.0 2.0 3.0 4.0 6.2 6.3 6.4 6.5 6.6 6.7 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 6.2 6.3 6.4 6.5 6.6 6.7 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 6.2 6.3 6.4 6.5 6.6 6.7 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 6.2 6.3 6.4 6.5 6.6 6.7 50 150 250 350 450 550 Output Current IOUT [A] Output Voltage VOUT [V] Time [ms] Vout Iout 0.0 1.0 2.0 3.0 4.0 6.2 6.3 6.4 6.5 6.6 6.7 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 6.2 6.3 6.4 6.5 6.6 6.7 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout

No. EY-404-201112 VOUT = 6.5 V, VIN = 12 V, fOSC = 500 kHz VOUT = 6.5 V, VIN = 12 V, fOSC = 500 kHz IOUT = 0 A → 3 A, Mode = H, Tr = 1 A/μs IOUT = 3 A → 0 A, Mode = H, Tf = 1 A/μs 10) Load Regulation VOUT = 3.3 V, fOSC = 500 kHz, Mode = L VOUT = 3.3 V, fOSC = 500 kHz, Mode = H VOUT = 5.0 V, fOSC = 500 kHz, Mode = L VOUT = 5.0 V, fOSC = 500 kHz, Mode = H 0.0 1.0 2.0 3.0 4.0 6.2 6.3 6.4 6.5 6.6 6.7 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 0.0 1.0 2.0 3.0 4.0 6.2 6.3 6.4 6.5 6.6 6.7 100 200 300 400 500 600 700 Output Current IOUT [A] Output Voltage VOUT [V] Time [μs] Vout Iout 3.25 3.26 3.27 3.28 3.29 3.30 3.31 3.32 3.33 3.34 3.35 0 1000 2000 3000 Output Voltage VOUT [V] Output Current IOUT [mA] Vin=8V Vin=12V Vin=16V Vin=24V 3.25 3.26 3.27 3.28 3.29 3.30 3.31 3.32 3.33 3.34 3.35 0 1000 2000 3000 Output Voltage VOUT [V] Output Current IOUT [mA] Vin=8V Vin=12V Vin=16V Vin=24V 4.97 4.98 4.99 5.00 5.01 5.02 5.03 5.04 5.05 5.06 0 1000 2000 3000 Output Voltage VOUT [V] Output Current IOUT [mA] Vin=8V Vin=12V Vin=16V Vin=24V 4.97 4.98 4.99 5.00 5.01 5.02 5.03 5.04 5.05 5.06 0 1000 2000 3000 Output Voltage VOUT [V] Output Current IOUT [mA] Vin=8V Vin=12V Vin=16V Vin=24V

No. EY-404-201112 VOUT = 6.5 V, fOSC = 500 kHz, Mode = L VOUT = 6.5 V, fOSC = 500 kHz, Mode = H 11) Line Regulation VOUT = 3.3 V, fOSC = 500 kHz, Mode = L VOUT = 3.3 V, fOSC = 500 kHz, Mode = H VOUT = 5.0 V, fOSC = 500 kHz, Mode = L VOUT = 5.0 V, fOSC = 500 kHz, Mode = H 6.43 6.45 6.47 6.49 6.51 6.53 6.55 6.57 6.59 0 1000 2000 3000 Output Voltage VOUT [V] Output Current IOUT [mA] Vin=12V Vin=16V Vin=24V 6.43 6.45 6.47 6.49 6.51 6.53 6.55 6.57 6.59 0 1000 2000 3000 Output Voltage VOUT [V] Output Current IOUT [mA] Vin=12V Vin=16V Vin=24V 3.0 3.1 3.2 3.3 3.4 0 5 10 15 20 25 30 Output Voltage VOUT [V] Input Voltage VIN [V] 0.01A 0.1A 3.0 3.1 3.2 3.3 3.4 0 5 10 15 20 25 30 Output Voltage VOUT [V] Input Voltage VIN [V] 0.01A 0.1A 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 0 5 10 15 20 25 30 Output Voltage VOUT [V] Input Voltage VIN [V] 0.01A 0.1A 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 0 5 10 15 20 25 30 Output Voltage VOUT [V] Input Voltage VIN [V] 0.01A 0.1A

No. EY-404-201112 VOUT = 6.5 V, fOSC = 500 kHz, Mode = L VOUT = 6.5 V, fOSC = 500 kHz, Mode = H 12) Transient Voltage Surge fOSC = 250 kHz, VIN = 12 V ↔ 30 V fOSC = 250 kHz, VIN = 12 V ↔ 30 V Mode = L, IOUT = 0.1 A Mode = H, IOUT = 0.1 A 13) Cranking fOSC = 250 kHz fOSC = 250 kHz Mode = L, IOUT = 0.1 A Mode = L, IOUT = 0.1 A 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 0 5 10 15 20 25 30 Output Voltage VOUT [V] Input Voltage VIN [V] 0.01A 0.1A 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 0 5 10 15 20 25 30 Output Voltage VOUT [V] Input Voltage VIN [V] 0.01A 0.1A 4.4 4.6 4.8 5.0 5.2 5 10 15 20 25 30 Input Voltage VIN [V] Output Voltage VOUT [V] Time [ms] Vout Vin 4.4 4.6 4.8 5.0 5.2 5 10 15 20 25 30 Input Voltage VIN [V] Output Voltage VOUT [V] Time [ms] Vout Vin Input Voltage VIN [V] Output Voltage VOUT [V] Time [s] Vout Vin 3 4 5 6 7 8 9 10 11 12 13 14 15 Input Voltage VIN [V] Output Voltage VOUT [V] Time [s] Vout Vin

No. EY-404-201112 fOSC = 250 kHz fOSC = 250 kHz Mode = H, IOUT = 0.1 A Mode = H, IOUT = 0.1 A Input Voltage VIN [V] Output Voltage VOUT [V] Time [s] Vout Vin 3 4 5 6 7 8 9 10 11 12 13 14 15 Input Voltage VIN [V] Output Voltage VOUT [V] Time [s] Vout Vin

No. EY-404-201112 Test Circuit MODE CSS/TRK GND LX RTOP RBOT 39kΩ RCCC RPG 100kΩ CBST 0.1µF CVCC 1.0µF L COUT CIN 21µF (10x2+1µF) VOUT CE PGOOD COMP VOUT FB CSS 15nF CC2 NC VIN VCC BST R1276Sxxxx VIN GND RT GND NC RRTCSPD RCE 1kΩ CE Control Test Circuit for Typical Characteristics Measurement Components of Typical Characteristics R1276SxxxA/C Constant Table Code (xxx) FOSC [kHz] VOUT [V] L [µH] COUT [µF] CSPD [pF] RTOP [kΩ] RRT [kΩ] RC [kΩ] CC [nF] CC2 [pF] 001 250 3.3 15 200 (100×2) 100 162 (150+12) 121 (220ǁ270) 22 10 100 5.0 22 200 (100×2) 100 267 (240+27) 121 (220ǁ270) 27 10 100 500 3.3 10 66 (22×3) 22 162 (150+12) 56 22 3.3 33 5.0 10 100 22 267 (240+27) 56 22 4.7 33 1000 3.3 4.7 48.7 (22×2+4.7) 22 162 (150+12) 28.7 (220ǁ33) 12 3.3 15 5.0 4.7 48.7 (22×2+4.7) 22 267 (240+27) 28.7 (220ǁ33) 12 3.3 15 002 500 6.5 15 147 (100+47) 22 357 (330+27) 56 22 4.7 33 004 250 0.7 3.3 430 (100+330) 1500 3.7 (2.2+1.5) 121 (220ǁ270) 5.1 47 150 ǁ: Parallel connection

No. EY-404-201112 Measurement Components of Typical Characteristics Symbol Specification Manufacture Parts number Capacitor CIN 1.0 µF, 50 V, 125°C TDK CGA4J3X7R1H105K 10 µF, 50 V, 125°C CGA6P3X7S1H106K CBST 0.1 µF, 25 V, 125°C CGA3E2X7R1E104K CVCC 1.0 µF, 16 V, 125°C CGA3E1X7R1V105K COUT 4.7 µF, 25 V, 125°C CGA5L1X7R1E475K 22 µF, 16 V, 125°C CGA6P1X7R1C226M 47 µF, 16 V, 125°C CGA9N3X7R1C476M 100 µF, 16 V, 125°C CKG57NX7S1C107M Inductor L 3.3 µH, 5.0 A TDK CLF7045T-3R3-D 4.7 µH, 5.4 A CLF10040T-4R7N-D 10 µH, 6.7 A CLF12555T-100M-D 15 µH, 5.4 A CLF12555T-150M-D 22 µH, 4.2 A CLF12555T-220M-D

Ver. B i The power dissipation of the package is dependent on PCB material, layout, and environmental conditions. The following measurement conditions are based on JEDEC STD. 51-7. Measurement Conditions Item Measurement Conditions Environment Mounting on Board (Wind Velocity = 0 m/s) Board Material Glass Cloth Epoxy Plastic (Four-Layer Board) Board Dimensions 76.2 mm × 114.3 mm × 0.8 mm Copper Ratio Outer Layer (First Layer): Less than 95% of 50 mm Square Inner Layers (Second and Third Layers): Approx. 100% of 50 mm Square Outer Layer (Fourth Layer): Approx. 100% of 50 mm Square Through-holes φ 0.3 mm × 21 pcs Measurem ent Result (Ta = 25°C , Tjmax = 150°C) Item Measurement Result Power Dissipation 3900 mW Thermal Resistance (θja) θja = 32°C/W Thermal Characterization Parameter (ψjt) ψjt = 8°C/W θja: Junction-to-Ambient Thermal Resistance ψjt: Junction-to-Top Thermal Characterization Parameter Power Dissipation vs. Ambient Temperature Measurement Board Pattern 500 1000 1500 2000 2500 3000 3500 4000 0 25 50 75 100 125 150 Power Dissipation PD (mW) Ambient Temperature (°C) 3900

PACKAGE DIMENSIONS HSOP-18 i Ver. A

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Summary

30 V, 3 A Synchronous Step-down DC/DC Converter for IndustrialApplications

Description