SM8172A

SM8172A NPC | Alldatasheet

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SEIKO NPC CORPORATION —1 2-output Power Supply IC 1. OVERVIEW The SM8172A is a 2-output power supply IC that incorporates a step-down DC/DC converter and series regu- lator with built-in reset circuit. The DC/DC converter is a PWM-type synchronous rectifier. The SM8172A has soft start, overcurrent detection, supply undervoltage lockout, and thermal shutdown circuits built-in, making it ideal as a supply voltage source IC for large-scale LSIs that operate from a 5V supply. 2. FEATURES I Input voltage range: 4.5 to 5.5V I Standby current: 0.01 µ A (typ) I Series regulator

• Feedback-type current limiter to reduce output current when outputs are short-circuit
• Output voltage: 3.3V (available for optional setting from 2.1 to 3.6V by 0.1V-step)
• Maximum output current: 450mA
• V oltage accuracy: 2% (VIN = 5.0V , Ta = 25 I DC/DC converter
• Current-mode operation for excellent transient response
• Output voltage: 0.8 to 1.8V (typ, selectable by external resistor)
• Maximum output current: 900mA
• Operating frequency: 2MHz (typ)
• V oltage accuracy: (FB pin, VIN = 5.0V , Ta = 25 C, DCOUT = 1.0V) I Reset circuit built-in
• Reset detection voltage: 3.7V (typ) (available for optional setting from 3.2 to 4.2V by 0.1V-step)
• Reset return delay time: 65ms (typ) (50ms, 32ms, 16ms, and 8ms selectable with option) I Various protection circuit built-in
• Startup soft start circuit built-in
• Overtemperature thermal shutdown (TSD) circuit built-in
• Supply undervoltage lockout (UVLO) circuit built-in I Package: 10-pin SON 3. APPLICATIONS I ODD I DVD player/recorder I Next-generation DVD player/recorder I Electronic equipment 4. TYPICAL APPLICATION CIRCUIT Note. RESETN is open-drain, therefore, please take care so that the High level signal does not exceed the absolute maximum rating of IC which receives the reset signal. Besides, if the rest signal is not used, RESETN should be connected to GND. 5. ORDERING INFORMATION VIN1 RESETN PGND LDOUT FB LX RESETN output Regulator output 3.3µF L 2.2µH 8pF 220kΩ 330kΩ 4.7µF DCOUT (1.0V) 10µF 5.0V VIN2 GND ENDCO ENLDO DC/DC control Regulator control 10µF 10kΩ Device Package SM8172AD 10-pin SON

SEIKO NPC CORPORATION —2 6. PINOUT (Top view) 7. PIN DESCRIPTION 8. BLOCK DIAGRAM Number Name I/O Function

1 VIN2 – Supply voltage (series regulator, internal circuits)

*1. VIN1 and VIN2 should have the same voltage potential.

2 LDOUT O Series regulator output

*2. When the series regulator is not used, LDOUT pin should be open and not be connected to GND.

3 GND – Ground (internal circuits)

4 ENDCO Ip

*3. Ip = Input with pull-down resistor built-in Output enable (DC/DC converter)

5 ENLDO Ip

Output enable (series regulator)

6 PGND – Ground (DC/DC converter output circuit)

7 LX O DC/DC converter coil drive

*4. When the DC/DC converter is not used, LX pin should be open and not be connected to GND or the supply.

8 VIN1 – Supply voltage (DC/DC converter output circuit)

9 FB I DC/DC converter feedback connection

*5. When the DC/DC converter is not used, FB pin should be connected to GND.

10 RESETN O Reset signal output (active-LOW, open-drain output)

*6. When the reset signal is not used, RESETN pin should be connected to GND. VIN2 LDOUT GND ENDCO ENLDO RESETN FB VIN1 LX PGND VIN2 RESETN Delay circuits Current protection ENDCO GND VIN2 detector Soft start Vref ERR LDOUT Thermal protection OSC Soft start Current protection ERR FB Current mode PWM control Output control VIN1 LX PGND RESETN output LDOUT output (3.3V) 3.3µF 5.0V 10µF 2.2µH 10kΩ 4.7µF DCOUT (1.0V) 10µF 5.0V ENLDO 8pF 220kΩ 330kΩ

SEIKO NPC CORPORATION —3 9. ABSOLUTE MAXIMUM RATINGS Note. The device may be damaged or deteriorated if any of the above parameter ratings is exceeded. 10. RECOMMENDED OPERATING CONDITIONS Parameter Symbol Rating Unit Supply voltage range V IN 0.3 to 6.0 V Input pin voltage range V ENDCO , V ENLDO , V FB 0.3 to V IN + 0.3 V Output pin voltage range 1 V LX , V LDOUT 0.3 to V IN + 0.3 V Output pin voltage range 2 V RESETN 0.3 to 6.0 V LX output current I LX 1.5 A LDOUT output current I LDOUT 700 mA Power dissipation P D 2000 (Ta = 25 *1. 101.5 105.0 1.6mm, wiring ratio 250%, FR-4, 4-layer board (thermal vias, die pad connections) Note that the ratings will vary depending on the board specifications, footprint pattern, and other factors. mW Junction temperature T JMAX +125 C Storage temperature range T stg 55 to +125 C Parameter Pin Symbol Conditions Rating Unit min typ max Supply voltage VIN1, 2 V IN VIN1 = VIN2 4.5 5.0 5.5 V Operating ambient temperature Ta 20 +25 +85 C 500 1000 1500 2000 2500 Ambient temperature Ta [°C] Power dissipation PD [mW] 50 75

SEIKO NPC CORPORATION —4 11. ELECTRICAL CHARACTERISTICS Note. The specifications of “ELECTRICAL CHARACTERISTICS” are shown by using “TYPICAL APPLI- CATION CIRCUIT” on page 13. 11-1. Common Blocks VIN1 = VIN2 = 5.0V , GND = PGND = 0V , Ta = 25 C unless otherwise noted. 11-2. Series Regulator VIN1 = VIN2 = 5.0V , GND = PGND = 0V , Ta = 25 C unless otherwise noted. Parameter Pin Symbol Condition Rating Unit min typ max Standby current VIN1, 2 I STB Standby mode (ENDCO = ENLDO = L), No load on inputs/outputs – 0.01 1 µ A HIGH-level input voltage ENDCO, ENLDO V IH 1.8 – – V LOW-level input voltage V IL – – 0.6 V HIGH-level input current I IH – 5.0 10 µ A RESETN output current RESETN I RESETN V RESETN = 1.0V 20 – – mA Reset circuit operating voltage VIN2 V RESETNL When VIN falls 3.5 3.7 3.9 V V RESETNH When VIN rises 3.7 3.9 4.1 V Reset circuit return delay time RESETN t RESETN When VIN rises – 65 – ms Under voltage lockout VIN2 V UVLOL When VIN falls 2.7 3.0 3.3 V V UVLOH When VIN rises 2.9 3.2 3.5 V TSD operating temperature – T SD – 170 – C TSD hysteresis – T SDHYS –2 0– C Parameter Pin Symbol Condition Rating Unit min typ max Current consumption VIN1, 2 I DD_LDO No load – 0.1 0.25 mA Soft start time LDOUT t SS_LDO 0.5 1 2 ms Output voltage LDOUT V LDO I LDO = 10mA 3.23 3.3 3.37 V Maximum output current *1. The output voltage difference at I LDO = 1mA and I LDO = 450mA is within 3%. LDOUT I LDO VIN2 = 4.5V, LDOUT = 3.3V 450 – – mA Input stability LDOUT V OUT1 4.5V VIN2 5.5V, I LDO Load stability LDOUT V OUT2 VIN2 = 5.0V, 1mA I LDO 300mA – 40 – mV Overcurrent protection circuit operating current LDOUT I OS – 700 – mA

SEIKO NPC CORPORATION —5 11-3. DC/DC Converter VIN1 = VIN2 = 5.0V , GND = PGND = 0V , Ta = 25 C unless otherwise noted. Parameter Pin Symbol Condition Rating Unit min typ max Current consumption 1 VIN1, 2 I DD1 No load, switching stopped – 0.35 0.75 mA Current consumption 2 VIN1, 2 I DD2 FB = VIN1, LX = Open – 2.5 5.5 mA Soft start time *1*2 *1. The soft start time is the interval during which the output current is limited internally in the IC, and is different from t he DC/DC converter output raise time. If the maximum load current is output after soft start time startup, the output voltage does not fall. But, if the maximu m load current is output before soft start time startup, it should be careful that the output voltage may fall. The LX starts the switching operation after 42 µ s from ENDCO rising. After switching operation startup, the output current limit operates like linear increase (load current = 0A). The DC/DC converter output voltage rise time varies with the load current, output capacitance, and other conditions. SS 0.2 0.6 1.0 ms Output voltage range DCO 0.8 – 1.8 V FB voltage FB V FB 0.588 0.6 0.612 V Maximum output current *2*3 DCO 900 – – mA Switching frequency LX f OSC 1.7 2.0 2.3 MHz Supply-side switch ON resistance LX R ONP I DCO = 50mA – 0.3 – Ω GND-side switch ON resistance LX R ONN I DCO = –50mA – 0.3 – Ω LX leakage current LX I LEAKLX Standby mode, LX = 1/2VIN –1.0 – 1.0 µ A Overcurrent protection circuit operating current LX I LIMITLX Supply-side switch – 1.5 – A ENDCO Current limit 42µsec (typ) High Low DCOUT 28µsec (typ) 1.5A (typ) 1.8V 1.0V Soft start time LX switching start

SEIKO NPC CORPORATION —6 *3. The output voltage difference at I DCO = 100mA and I DCO = 900mA is within 3%. I Accuracy of output voltage The accuracy of DCOUT output voltage is affected by the FB pin voltage accuracy (0.6V 2%) and the exter- nal resistor accuracy (R1, R2). If the external resistor of 1% accuracy is used, the accuracy of DCOUT output voltage shows 3% accuracy including the FB pin voltage accuracy 2%. *2. The DC/DC converter output voltage (DCOUT) is determined by the external resistors as given by the following equation. The SM8172A DC/DC con- verter controls the output to maintain the FB pin voltage of 0.6V. DCOUT = 0.6 × (R1 + R2) SM8172 DCOUT FB LX Example settings DCOUT [V] R1 [k Ω] R2 [k Ω] C3 [pF] 0.8 200 600 8 1.000 200 300 8 1.200 200 200 8 1.502 200 133 8 1.800 200 100 8 The E-12 series usage example DCOUT [V] R1 [k Ω] R2 [k Ω] C3 [pF] 1.0 220 330 8 1.2 220 220 8 1.5 150 100 10

SEIKO NPC CORPORATION —7 12. FUNCTIONAL DESCRIPTION 12-1. Series Regulator 12-1-1. Basic Operation The SM8172A is equipped with a series regulator that drives a maximum 450mA load current at a fixed 3.3V output voltage. 12-1-2. Soft Start Function A soft start circuit is built-in to prevent output voltage overshoot and inrush current at startup. The soft start time is the interval during which the output current is limited internally in the IC, and is different from the series regulator output voltage rise time. The time varies with the load current, output capacitance, and other conditions. 12-1-3. Overcurrent Protection Function The series regulator overcurrent protection function uses a foldback method. When the output current exceeds the overcurrent protection circuit operating current limit value of 700mA (typ), the output current and output voltage are dropped, and the output short-circuit current is 80mA (typ). Normal operation is restored when the overcurrent condition is resolved. 3.3V (typ) LDOUT (regulator output) Output short-circuitcurrent80mA (typ) Overcurrent protectioncurrent700mA (typ) ILDOUT (regulator output current)

SEIKO NPC CORPORATION —8 12-2. DC/DC Converter 12-2-1. Basic Operation The SM8172A DC/DC converter is a step-down converter that is controlled using a 2MHz switching frequency current-mode PWM waveform, and which incorporates a MOSFET synchronous rectifier. 12-2-2. Soft Start Function A soft start circuit is built-in to prevent output voltage overshoot and inrush current at startup. The soft start time is the interval during which the output current is limited internally in the IC, and is different from the DC/DC converter output voltage rise time. The time varies with the load current, output capacitance, and other conditions. 12-2-3. Overcurrent Protection Function The P-channel MOSFET is turned OFF when the inductor current exceeds the current limit (1.5A). Normal operation is restored when the overcurrent condition is resolved. 12-3. Reset Function When the supply voltage is within the rated range, the RESETN output is high-impedance (Hi-Z). When the supply voltage falls below 3.7V (typ), the undervoltage detector circuit operates, setting the RESETN output LOW. When the supply voltage subsequently rises above 3.9V (typ), the RESETN output goes high-impedance again. However, when the supply voltage rises above 3.9V (typ), a built-in delay circuit sets the RESETN out- put to high-impedance after a delay of 65ms (typ). When at standby status, the RESETN output is LOW. When standby status is released, the RESETN output goes high-impedance after delay time if the supply voltage is more than 3.9V (typ). Inductor current Overcurrent detector Pch MOS OFF Overloaded status Normal operation when resolving overload 1.5A VIN1 Output control LX

SEIKO NPC CORPORATION —9 12-4. Supply Undervoltage Lockout Function In addition to the reset function, when the VIN2 supply falls below 3.0V (typ), the undervoltage lockout func- tion operates, stopping the DC/DC converter and series regulator outputs. When the VIN2 supply subsequently rises above 3.2V (typ), the outputs start again. *1. A time interval example for a typical application circuit with no load. The series regulator and DC/DC converter output voltage rise times may vary with the load current, output capacitance, and other conditions. *2. The soft start time is the interval during which the output current is limited internally in the IC, and is different from the series regulator and DC/DC con- verter output raise time. DC/DC, regulator output stop by UVLO lockout VRESETN (Pull-up) Reset return delay time 65msec (typ) VDCOUT VLDOUT LDOUT (regulator output) DCOUT (DC/DC output) VRESETNH VRESETNL VUVLOH VUVLOL VIN2 70µsec (typ) LDOUT (regulator output) DCOUT (DC/DC output) DC/DC soft start time 0.6msec (typ) LDO soft start time 1msec (typ) 800µsec (typ)*1

SEIKO NPC CORPORATION —10 12-5. Thermal Shutdown (TSD) Protection Circuit When the chip temperature rises above approximately 170°C (typ) for any reason whatsoever, the thermal shut- down circuit operates, stopping all outputs. When the chip temperature falls below 150 °C (typ), the outputs start again. 12-6. State of Each Output when Protection Function Operates The output states of RESETN, DCOUT, and LDOUT when various circuit protection functions operate are shown in the following table. Note. The RESETN output is unaffected by the overcurrent protection function. The DCOUT and LDOUT outputs are unaffected by the reset voltage. *1. A time interval example for a typical application circuit with no load. The series regulator and DC/DC converter output voltage rise times may vary with the load current, output capacitance, and other conditions. *2. The soft start time is the interval during which the output current is limited internally in the IC, and is different from the series regulator and DC/DC con- verter output raise time. Pins Normal operation When various protection functions operate RESET voltage VIN2 ≤ 3.9V (typ) Under voltage lockout VIN2 ≤ 3.2V (typ) TSD TSD = 170°C (typ) Series regulator overcurrent protection IOS = 700mA (typ) DC/DC converter overcurrent protection ILIMITLX = 1.5A (typ) RESETN Hi-Z L L L Hi-Z Hi-Z DCOUT*1 *1. When the DC/DC converter output voltage is set to 1.0V. 1.0V 1.0V 0V (Disable) 0V (Disable) 1.0V < 1.0V LDOUT 3.3V 3.3V 0V (Disable) 0V (Disable) < 3.3V 3.3V VDCOUT VLDOUT TSD

170 C (typ)

DC/DC, regulator output stop by thermal shutdown VRESETN (Pull-up) LDOUT (regulator output) DCOUT (DC/DC output) TSD-TSDHYS

150 C (typ)

[ C] LDOUT (regulator output) DCOUT (DC/DC output) 70µsec (typ) DC/DC soft start time 0.6msec (typ) LDO soft start time 1msec (typ) 800µsec (typ)*1 Reset return delay time 65msec (typ)

SEIKO NPC CORPORATION —11 12-7. Standby Mode When both ENDCO and ENLDO are LOW, the device switches to standby mode, and all the RESETN, con- verter, and regulator outputs stop. 12-8. Timing Diagrams 12-8-1. Supply Voltage (VIN1 = VIN2 = ENDCO = ENLDO) *1. A time interval example for a typical application circuit with no load. The series regulator and DC/DC converter output voltage rise times may vary with the load current, output capacitance, and other conditions. *2. The soft start time is the interval during which the output current is limited internally in the IC, and is different from the series regulator and DC/DC con- verter output raise time. Note. When the supply voltage is below approximately 0.8V, there is insufficient drive for the IC to operate normally and the RESETN output level is unde- fined. Normally, a pull-up resistor is connected to RESETN, which sets the RESETN output level to pull-up voltage. VIN1 VIN2 ENABLE VRESETN (Pull-up) VDCOUT VLDOUT VRESETNH VRESETNL VUVLOH VUVLOL DC/DC, regulator output permission DC/DC, regulator output stop by UVLO lockout LDOUT (regulator output) DCOUT (DC/DC output) 70µsec (typ) DC/DC soft start time 0.6msec (typ) LDO soft start time 1msec (typ) 800µsec (typ)*1 Reset return delay time 65msec (typ)

SEIKO NPC CORPORATION —12 12-8-2. Enable Control *1. A time interval example for a typical application circuit with no load. The series regulator and DC/DC converter output voltage rise times may vary with the load current, output capacitance, and other conditions. *2. The soft start time is the interval during which the output current is limited internally in the IC, and is different from the series regulator and DC/DC con- verter output raise time. ENDCO ENLDO VDCOUT VLDOUT VRESTEN (pull-up) Standby mode when both ENDCO and ENLDO are LOW level Reset return delay time 65ms (typ) 70µsec (typ) DC/DC soft start time 0.6msec (typ) LDO soft start time 1msec (typ) 800µsec (typ)*1

SEIKO NPC CORPORATION —13 13. TYPICAL APPLICATION CIRCUIT Note. RESETN is open-drain, therefore, please take care so that the High level signal does not exceed the absolute maximum rating of IC which receives the reset signal. Besides, if the rest signal is not used, RESETN should be connected to GND. Recommended parts list L : 2.2 µH 1002AS-2R2M (TOKO) NR4018T2R2M (TAIYO YUDEN) VLF4014ST2R2M1R9 (TDK) R1, R2 : 220k Ω, 330kΩ – R3 : 10k Ω – C1, C2 : 10 µF Ceramic Capacitor C2012X5R1A106K (TDK) Ceramic Capacitor GRM219B31A106K (Murata) C3 : 8pF Ceramic Capacitor C4 4.7 µF Ceramic Capacitor GRM219B31A475K (Murata) C5 : 3.3 µF Ceramic Capacitor GRM219B31A335K (Murata) VIN1 RESETN PGND LDOUT FB LX RESETN output Regulator output 3.3µF L 2.2µH 8pF 220kΩ 330kΩ 4.7µF DCOUT (1.0V) 10µF 5.0V VIN2 GND ENDCO ENLDO DC/DC control Regulator control 10µF 10kΩ

SEIKO NPC CORPORATION —14 14. USAGE NOTES 14-1. Select of Inductance (L) It recommends 2.2 µH of Inductance (L) for SM8172A. Since the DC resistance of inductance affects the power efficiency, we recommend the inductance of low DC resistance. Besides, please take care so that the inductance peak current (Ipeak) does not exceed the maximum allowable current of inductor. 14-2. External Capacitor Type The external capacitors connected to the SM8172A should be multi-layer ceramic capacitors, with low temper- ature coefficient X5R or X7R class (EIA standard) multi-layer ceramic capacitors recommended. Use of high temperature coefficient Z5U or Y5V class multi-layer ceramic capacitors may cause an unstable output voltage condition and should be avoided. 14-3. VIN Supply Input Capacitor In some cases, the printed board component layout may affect the stability of the output voltages. In such cases, the VIN power supply capacitor should be increased or an additional capacitor connected. Capacitor temperature coefficient 3-letter codes (EIA standard) Lower category temperature Upper category temperature Maximum deviation in capacitance from +25°C (0V DC) value T = +22%/−33% U = +22%/−56% V = +22%/−82% Selection : X5R characteristics

SEIKO NPC CORPORATION —15 14-4. Mounting The package rear surface is metallic, and can be connected to the printed circuit board pattern as a heatsink. The connected pattern should be tied to GND level. Furthermore, use of a thermal via structure on the PCB or other technology should be used to provide suf ficient heat dissipation. Use a printed circuit board with 4 or more layers. The PCB wiring ratio *1 should exceed 200%, where the wiring ratio is the sum total of printed wiring pattern surface area relative to the circuit board surface area. *1: Determining the wiring pattern ratio Example: 4-layer board with the same wiring pattern on 4 layers (left), where the wiring pattern surface area on each layer is represented by S1, and the non-wired surface area is represented by S2. The wiring pattern is connected directly to the IC, and each layer ’s wiring pattern is connected to the IC by through holes. The circuit board surface area seen from above is S1 + S2. First, calculate the board surface area, here represented by S1 + S2. Next, calculate the wiring pattern surface area on each layer connected to the IC, represented here by S1. Calculate the total wiring pattern surface area for all 4 layers, in this example 4 × S1. Finally, calculate the wiring ratio percentage using the following equation: (Wiring ratio) = (Total wiring pattern surface area connected to the IC) / (PCB surface area) × 100. In this example, 4 × S1/(S1 + S2) × 100 [%], or a wiring ratio of 200% when S1 = S2. S1 S2

SEIKO NPC CORPORATION —16 15. PACKAGE DIMENSION (Unit: mm) 521 Top view 2.50 ± 0.07 10 6 A 1.25 B 1.50 3.00 ± 0.07

0.10 S A B

S 0.10 S 0.5 0.05 S 0.05max 0.70 ± 0.05 0.75max Bottom view 61 0 1.64 0.40 ± 0.07 1.34 52 1 0.50 4 = 2.00 ± 0.05 0.14 C0.25 φ 0.05 S A B0.22 ± 0.05 M

Please pay your attention to the following points at time of using the products shown in this document. 1. The products shown in this document (hereinafter ”Products”) are designed and manufactured to the generally accepted standards of reliability as expected for use in general electronic and electrical equipment, such as personal equipment, machine tools and measurem ent equipment. The Products are not designed and manufactured to be used in any other special equipment r equiring extremely high level of reliability and safety, such as aerospace equipment, nuclear power control equipment, medical equipment, transportation equipment, disaster prevention equipment, security equipment. T he Products are not designed and manufactured to be used for the apparatus that exerts harmful influence on the hum an lives due to the defects, failure or malfunction of the Products. If you wish to use the Products in that apparatus, please contact our sales section in advance. In the event that the Products ar e used in such apparatus without our prior approval, we assume no responsibility whatsoever for any damages resulting from the use of that apparatus. 2. NPC reserves the right to change t he specifications of the Pr oducts in order to improve the characteristics or reliability thereof. 3. The information described in this document is presented only as a guide for using the Products. No responsibility is assumed by us for any infringements of patents or other rights of the third parties which may result from its use. No license is granted by implication or otherwise under any patents or other ri ghts of the third parties. Then, we assume no responsibility whatsoever for any damages resulting from that infringements. 4. The constant of each circuit shown in this document is described as an example, and it is not guaranteed about its value of the mass production products. 5. In the case of that the Products in this document falls under the fo reign exchange and foreign trade control law or other applicable laws and regulations, approval of t he export to be based on those laws and regulations are necessary. Customers are requested appropriately take st eps to obtain required permissions or approvals from appropriate government agencies. SEIKO NPC CORPORATION 1-9-9, Hatchobori, Chuo-ku, Tokyo 104-0032, Japan Telephone: +81-3-5541-6501 Facsimile: +81-3-5541-6510 http://www.npc.co.jp/ Email:sales@npc.co.jp NC0804AE 2009.09 SEIKO NPC CORPORATION —17