Power Management

BD8P250MUF-C

Rohm

2.7 V to 36 V Input, 2 A Single Buck DC/DC Converter with Boost Function For Automotive

Manufacturer: Rohm

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Technical content

Features

 Quick Buck Booster®  Nano Pulse Control™  AEC-Q100 Qualitied (Note 1)  Boost Control Function  LLM(Light Load Mode)  Spread Spectrum Function  Power Good Function  Soft Start Function  Current Mode Control  Phase Compensation Included  Over Current Protection  Input Under Voltage Lockout Protection  Thermal Shutdown Protection  Output Over Voltage Protection  Short Circuit Protection  Wettable Flank QFN Package (Note 1) Grade 1

Applications

 Automotive Equipment (Cluster Panel, Infotainment Systems)  Other Electronic Equipment Key Specifications  Input Voltage A: 3.5 V to 36 V (Buck DC/DC Converter, Initial startup is over 4.8 V)  Input Voltage B: 2.7 V to 36 V (Buck-Boost DC/DC Converter, Initial startup is over 7.5 V)  Output Voltage: 5.0 V(Typ)  Output Current in Buck Operation: 2 A(Max)  Output Current in Buck-Boost Operation: 0.8 A(Max)  Switching Frequency: 2.2 MHz(Typ)  Shutdown Circuit Current: 3.5 µA(Typ)  Quiescent Current: 8 µA(Typ)  Operating Temperature: -40 °C to +125 °C Package W(Typ) x D(Typ) x H(Max) VQFN24FV4040 4.00 mm x 4.00 mm x 1.00 mm Typical Application Circuit A. Buck DC/DC Converter B. Buck-Boost DC/DC Converter (Use Exclusive Boost-FET) Figure 1. Application Circuit Quick Buck Booster® is a registered trademark of ROHM Co., Ltd. Nano Pulse Control™ is a trademark of ROHM Co., Ltd.

© 2018 ROHM Co., Ltd. All rights reserved. Figure 2. Pin Configuration V or higher) to turn this device on. This pin must be terminated. 2 VIN Power supply input pin of the internal circuitry. Connect this pin to PVIN pin. Power supply input pins that are used for the output stage of the switching regulator. 6 N.C No connection pin. Leave these pins open, or connect to PVIN pin. 7,8 PGND Ground pins for the output stage of the switching regulator. 9to10 N.C. No connection pin. Leave these pins open, or connect to PGND pin. 11 N.C. No connection pin. Leave this pin open. 15 BOOT Connect a bootstrap capacitor of 0.1 µF between this pin and the SW pins. The voltage of this capacitor is the gate drive voltage of the High Side FET . 16 N.C. No connection pin. Leave this pin open.

17 SSCG

Pin to select Spread Spectrum function. Connect this pin to VREG pin or GND pin. disable Spread Spectrum function.

18 CTLOUT

through a pull-down 1 kΩ resistor when not using the exclusive Boost-FET. through a pull-up resistor. Using a 10 kΩ to 100 kΩ resistance is recommended. 20 VOUT Sense pin of output voltage. This pin is controlled to become 5.0 V(Typ). 21 VCC_EX Internal power supply pin. Connect this pin to VOUT pin.

23 VREG

a ceramic capacitor with value of 1.0 µF(Typ) to ground.

24 MODE

via provides excellent heat dissipation characteristics.

GmAmp1 This block is an error amplifier and its inputs are the reference voltage VREF and the division voltage FB of VOUT pin. It controls the GmAmp1 output such that the VREF voltage and the FB voltage equal.
GmAmp2 This block sends the signal Vc which is composed of the GmAmp1 output and the current sense signal to PWM Comp.
Soft Start It is a function to prevent overshoot of inrush current and the output voltage by gradually raising the input reference voltage of GmAmp1 upon power supply ON. Soft start time is 1.0 ms(Typ).
OSC This block generates the clock frequency. Connect SSCG pin to GND pin to disable Spread Spectrum function and connect SSCG pin to VREG pin to enable it. This function becomes invalid when PGOOD output is Low or during Buck-Boost operation.
Ramp This block generates the saw tooth waveform Vr from the clock signal generated by OSC.
Current Sense This block detects the amount of change in inductor current through the Low Side FET and sends a current sense signal to GmAmp2.
Clamper This block clamps GmAmp1 output voltage and inductor current. It works as over current protection and LLM control current.
PWM Comp This block compares the saw tooth waveform Vr with the GmAmp2 output Vc and controls the duty cycle of the output switching pulse.
Control Logic This block receives the signal generated by the PWM Comp and outputs the control signal to the output MOSFET . In addition, it controls ON/OFF of the switching during light load and upon abnormal detection.
TSD This block is a thermal shutdown circuit. It will shut down the device to prevent thermal damage or a thermal-runaway of the device when the chip temperature reaches to approximately 175 °C(Typ) or more. When the chip temperature falls below the TSD threshold, the circuits are automatically restored to normal operation with hysteresis of 25 °C(Typ). Note that the thermal shutdown circuit is intended to prevent destruction of the device. Therefore, it is highly recommended to always keep the device temperature within Tjmax = 150 °C. Operation above operating temperature range will reduce the lifetime of the device. The restart need the input voltage like the startup. The regulator restarts the operation with soft start.
SCP This is the short circuit protection circuit. Turns OFF the output stage MOSFET for 15.4 ms (Typ) if it detects the VOUT pin voltage to be 55 % (T yp) or lower for 0.1 ms (Typ) or longer. Then, a restart is performed with the soft start. T he SCP functions is masked for 1.4 ms (Typ) after the soft start. The input voltage required for the restoration is the same as that for the startup.
OVP This is the output over voltage protection circuit. When it detects the VOUT pin voltage is 120 % (Typ) or more for 1 µs (Typ) or longer, the output MOSFET are turned OFF . When it detects the VOUT pin voltage is less than 120 % (Typ) for 7 µs (Typ) or longer, it returns to normal operation.
UVLO The UVLO block is for under voltage lockout protection. It will shut down the device when the VIN falls to 2.4 V(Typ) or lower. The release voltage is 4.45 V(Typ) when the exclusive Boost-FET is not used, and is 7.15 V(Typ) when used with the exclusive Boost-FET. The regulator restarts the operation with soft start when the release voltage is satisfied.
VREG This block is the internal power supply circuit. It outputs 5.0 V(Typ) and is the power supply to the control circuit and driver. The input of this block during startup is the VIN pin voltage. When the PGOOD output becomes Hig h, the VCC_EX pin voltage becomes its input supply, and consequently, high efficiency is achieved.
VREF The VREF block generates the internal reference voltage.

MODE When MODE pin is 2.0 V or more, the device works by forced PWM control. When MODE pin is 0.8 V or less, the device enables the LLM control and the mode is automatically switched between the LLM control and PWM control. However, during Buck-Boost operation, the device works on forced PWM control.
Driver This circuit drives the gates of the output MOSFET .
PGOOD When the VOUT pin voltage reaches within ±5 %, the built-in Nch MOSFET turns OFF and the PGOOD output turns High. In addition, the PGOOD output turns Low when the VOUT pin voltage reaches outside ±10 %.
POR The POR block is the input under voltage lockout protection for the internal power supply. It will shut down the device when the VREG voltage falls to 2.85 V (Typ) or less. When the release voltage of 3.0 V (Typ) is satisfied, the regulator restarts the operation with soft start.
SLEEP Comp This block controls the VOUT pin voltage in PFM control from 101 % of PWM control to 102 % of PWM control.
ZX Comp This block stops the switching by detecting the reverse SW output current at LLM control.
BOOST Comp, Boost Duty This is the control circuit of the Boost signal. When used with the exclusive Boost-FET, PGOOD output is High and the VIN pin voltage becomes 140 % (Typ) or less of the VOUT pin voltage, an ON pulse with 70 % (Typ) duty is output by CTLOUT pin and putting the device in Buck-Boost operation. It returns to Buck operation with 10 % (Typ) of hysteresis.
HOCP Comp This block limits current of the High Side FET . When it detects current of 4 A (Min) or more, High Side FET is turned OFF . This function works only in abnormal situations such as when the SW pin is shorted to GND.

11.Sep.2018 Rev.001 © 2018 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 www.rohm.com BD8P250MUF-C Absolute Maximum Ratings (Ta=25°C) Parameter Symbol Rating Unit Input Voltage VVIN, VPVIN -0.3 to +42 V EN Voltage VEN -0.3 to +42 V BOOT Voltage VBOOT -0.3 to +49 V Voltage from SW to BOOT ΔVBOOT -0.3 to +7 V MODE, SSCG, VOUT, VCC_EX, VREG, PGOOD, CTLOUT Voltage VMODE, VSSCG, VVOUT, VVCC_EX, VVREG, VPGOOD, VCTLOUT -0.3 to +7 V Maximum Junction Temperature Tjmax 150 ˚C Storage Temperature Range Tstg -55 to +150 ˚C Caution 1: Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins o r an open circuit between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated over the absolute maximum ratings. Caution 2: Should by any chance the maximum junction temperature rating be exceeded the rise in temperature of the chip may result in de terioration of the properties of the chip. In case of exceeding this absolute max imum rating, design a PCB with thermal resistance taken into consideration by increasing board size and copper area so as not to exceed the maximum junction temperature rating. Thermal Resistance (Note 1) Parameter Symbol Thermal Resistance (Typ) Unit 1s(Note 3) 2s2p(Note 4) VQFN24FV4040 Junction to Ambient θJA 107.4 32.6 °C/W Junction to Top Characterization Parameter(Note 2) ΨJT 9 4 °C/W (Note 1) Based on JESD51-2A(Still-Air). (Note 2) The thermal characterization parameter to report the difference between junction temperature and the temperature at the top center of the outside surface of the component package. (Note 3) Using a PCB board based on JESD51-3. (Note 4) Using a PCB board based on JESD51-5, 7. Layer Number of Measurement Board Material Board Size Single FR-4 114.3 mm x 76.2 mm x 1.57 mmt Top Copper Pattern Thickness Footprints and Traces 70 μm Layer Number of Measurement Board Material Board Size Thermal Via(Note 5) Pitch Diameter Top 2 Internal Layers Bottom Copper Pattern Thickness Copper Pattern Thickness Copper Pattern Thickness Footprints and Traces 70 μm 74.2 mm x 74.2 mm 35 μm 74.2 mm x 74.2 mm 70 μm (Note 5) This thermal via connects with the copper pattern of all layers.

11.Sep.2018 Rev.001 © 2018 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 www.rohm.com BD8P250MUF-C Recommended Operating Conditions Parameter Symbol Min Typ Max Unit Input Voltage A (Not use Exclusive Boost-FET) VINA 3.5 - 36 V Input Voltage B (Use Exclusive Boost-FET) VINB 2.7 - 36 V Operating Temperature Topr -40 - +125 ˚C Output Current in Buck Operation IOUTBUCK - - 2.0 A Output Current in Buck -Boost Operation IOUTBOOST - - 0.8 A SW Minimum ON Time(Note1) tONMIN - 45 - ns Input Capacitor(Note2) CIN 2.3 4.7 - µF VREG Capacitor(Note2) CREG 0.48 1.0 2.1 µF (Note 1) This parameter is for 1A output. Not 100 % tested. (Note 2) Ceramic capacitor is recommended. The capacitor value including temperature change, DC bias change, and aging change must be considered. Electrical Characteristics (Unless otherwise specified Ta = -40 ˚C to +125 ˚C, VIN = 12 V, VEN = 5 V) Parameter Symbol Limit Unit Conditions Min Typ Max VIN Shutdown Circuit Current ISDN - 3.5 7.0 µA VEN=0 V, Ta<105 °C Quiescent Current (VIN) IQVIN - 1.4 2.8 µA VMODE=0 V, VOUT=VVCC_EX=5.5 V, Ta<105 °C Quiescent Current (VOUT) IQVOUT - 16 32 µA VMODE=0 V, VOUT=VVCC_EX=5.5 V, Ta<105 °C UVLO Detection Voltage VUVLOL 2.2 2.4 2.6 V VIN Falling UVLO Release Voltage A VUVLOHA 4.25 4.45 4.65 V VIN Rising, CTLOUT Pin=0 V or 1 kΩ pull-down UVLO Release Voltage B VUVLOHB 6.9 7.15 7.4 V VIN Rising, CTLOUT Pin=Open or CTLIN Pin(Note 3) EN/MODE/SSCG EN Threshold Voltage High VENH 2.0 - VIN V EN Threshold Voltage Low VENL 0 - 0.8 V EN Input Current IEN - 0 1.0 µA VEN=5 V MODE Threshold Voltage High VMODEH 2.0 - 5.5 V MODE Threshold Voltage Low VMODEL 0 - 0.8 V MODE Input Current IMODE - 0 1.0 µA VMODE=5 V SSCG Threshold Voltage High VSSCGH 2.0 - 5.5 V SSCG Threshold Voltage Low VSSCGL 0 - 0.8 V SSCG Input Current ISSCG - 0 1.0 µA VSSCG=5 V VREG VREG Voltage VREG 4.80 5.00 5.20 V POR Detection Voltage VPORL 2.70 2.85 3.00 V VVREG Falling (Note 3) CTLIN is the pin of exclusive boost-FET.

11.Sep.2018 Rev.001 © 2018 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 www.rohm.com BD8P250MUF-C Electrical Characteristics – continued (Unless otherwise specified Ta = -40 ˚C to +125 ˚C, VIN = 12 V, VEN = 5 V) Parameter Symbol Limit Unit Conditions Min Typ Max VOUT Output Voltage VOUT1 4.90 5.000 5.10 V PWM Control Output Voltage (LLM) (Note 4) VOUT2 4.90 5.075 5.25 V LLM Control, VMODE=0 V, Including output ripple Soft Start Time tSS 0.5 1.0 1.5 ms SW High Side FET ON Resistance RONH - 110 220 mΩ ISW=-50 mA Low Side FET ON Resistance RONL - 110 220 mΩ ISW=50 mA High Side FET Leakage Current ILEAKSWH - 0 10 µA VIN=36 V, VEN=0 V, VSW=0 V, Ta<105 ˚C Low Side FET Leakage Current ILEAKSWL - 0 10 µA VIN=36 V, V EN=0 V, V SW=36 Ta<105 ˚C Switching Frequency fSW 2.0 2.2 2.4 MHz Over Current Protection(Note 4) IOCP 3.1 3.6 4.1 A Spread Spectrum fSSCG - fSW x 110 % - MHz VSSCG=5 V Spread Spectrum Modulation Cycle tSSCGCYCLE - 220 - µs VSSCG=5 V PGOOD PGOOD Threshold Voltage 1 VPG1 VOUT1 x 92 % VOUT1 x 95 % VOUT1 x 98 % V VOUT Rising PGOOD Hysteresis Voltage 1 VPGhys1 - VOUT1 x -5 % - V VOUT Falling PGOOD Threshold Voltage 2 VPG2 VOUT1 x 102 % VOUT1 x 105 % VOUT1 x 108 % V VOUT Falling PGOOD Hysteresis Voltage 2 VPGhys2 - VOUT1 x +5 % - V VOUT Rising PGOOD Leakage Current IPGLEAK - 0 1 µA VPGOOD=5 V, VOUT=5.0 V PGOOD ON Resistance RPG - 250 500 Ω IPGOOD=1 mA, VEN=0 V SCP/OVP OVP Detection Voltage VOVP VOUT1 x 115 % VOUT1 x 120 % VOUT1 x 125 % V SCP Detection Voltage VSCP VOUT1 x 50 % VOUT1 x 55 % VOUT1 x 60 % V BOOST Buck-Boost Threshold Voltage VBOOST VOUT x 131 % VOUT x 140 % VOUT x 149 % V VIN Falling, CTLOUT Pin=Open or CTLIN Pin(Note 3) Buck-Boost Hysteresis Voltage VBOOSThys - VOUT x +10 % - V VIN Rising, CTLOUT Pin=Open or CTLIN Pin(Note 3) CTLOUT ON Duty DCTLOUT 66 70 74 % VIN=6.5 V, CTLOUT Pin=Open or CTLIN Pin(Note 3) (Note 3) CTLIN is the pin of exclusive boost-FET. (Note 4) This is design value. Not production tested.

© 2018 ROHM Co., Ltd. All rights reserved. beginning of the soft start. When EN pin voltage drops to 0.8 V or lower, the device is shut down. Figure 32. Enable ON/OFF Timing Chart impedance of 250 Ω (Typ). Using a resistance of 10kΩ to 100kΩ, pull it up to the VREG pin or the power supply. Figure 33. PGOOD Timing Chart

2.0 V VENL

Under Voltage Lockout Protection (UVLO/POR)

(Typ) or higher prompts the startup operation. Figure 34. UVLO/POR Timing Chart (Not Use Exclusive Boost-FET) Figure 35. UVLO/POR Timing Chart (Use Exclusive Boost-FET)

2.4 V(Typ)

4.45 V(Typ)

2.85 V(Typ)

3.0 V(Typ)

7.15 V(Typ)

© 2018 ROHM Co., Ltd. All rights reserved. Connecting the SSCG pin with VREG pin activates the Spread Spectrum function, reducing the EMI noise level. Figure 42. Spread Spectrum Function Timing Chart

2.2 MHz(Typ)

Over Current Protection (OCP)

OCP detection current for the output current is decreased during the buck-boost operation. Figure 43. Over Current Protection

Short Circuit Protection (SCP)

start. The input voltage required for the restoration is the same as that for the startup. Figure 44. SCP Timing Chart (Short Circuit Devision) Figure 45. SCP Tinimg Chart (Self Return)

3.6 A(Typ)

Over Voltage Protection (OVP)

(Typ) or longer. It is restored when VOUT pin voltage falls below the threshold for 7 μs (Typ) or longer. Figure 47. OVP Timing Chart

11.Sep.2018 Rev.001 © 2018 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 www.rohm.com BD8P250MUF-C Selection of Components Externally Connected - continued 1. Selection of the inductor L1 value Role of the inductor in the switching regulator is that it also serves as a filter for smoothing the output voltage to supply a continuous current to the load. The Inductor ripple current ΔIL that flows to the inductor becomes small when an inductor with a large inductance value is selected. Consequently, the voltage of the output ripple ΔVP-P also becomes small. It is the trade-off between the size and the cost of the inductor. The inductance of the inductor is shown in the following equation: 𝐿 = (𝑉𝐼𝑁(𝑀𝑎𝑥)−𝑉𝑂𝑈𝑇)×𝑉𝑂𝑈𝑇 𝑉𝐼𝑁(𝑀𝑎𝑥)×𝑓𝑆𝑊×∆𝐼𝐿 [H] Where: 𝑉𝐼𝑁 (𝑀𝑎𝑥) is the maximum input voltage 𝑉𝑂𝑈𝑇 is the output voltage 𝑓𝑆𝑊 is the switching frequency 𝛥𝐼𝐿 is the peak to peak inductor current In current mode control, sub-harmonic oscillation may happen. The slope compensation circuit is integrated into the IC in order to prevent sub -harmonic oscillation. The sub -harmonic oscillation depends on the rate of increase of output switch current. If the inductor value is too small, the sub -harmonic oscillation may happen because the inductor ripple current ΔIL is increased. And if the inductor value is too large, the feedback loop may not achieve stability because the inductor ripple current ΔIL is decreased. Therefore, use an inductor value of the inductor within the range of 2.2 µH to 10 µH. The smaller the ΔIL, the smaller the Inductor core loss (iron loss), and the smaller is the loss due to ESR of the output capacitor. In effect, ΔVP-P (Output peak-to-peak ripple voltage) will be reduced. ΔVP-P is shown in the following equation. ∆𝑉𝑃−𝑃 = ∆𝐼𝐿 × 𝐸𝑆𝑅 + ∆𝐼𝐿 8×𝐶𝑂𝑈𝑇×𝑓𝑆𝑊 [V] (a) Where: 𝐸𝑆𝑅 is the equivalent series resistance of the output capacitor 𝐶𝑂𝑈𝑇 is the output capacitance 𝛥𝐼𝐿 is the peak to peak inductor current 𝑓𝑆𝑊 is the switching frequency Generally, even if ΔIL is somewhat large, the ΔVP-P target is satisfied because the ceramic capacitor has a very-low ESR. It also contributes to the miniaturization of the application board. Also, because of the lower rated cur rent, smaller inductor is possible since the inductance is small. The disadvantages are increase in core losses in the inductor and the decrease in maximum output current. When other capacitors (electrolytic capacitor, tantalum capacitor, and electro conductive polymer etc.) are used for output capacitor C OUT, check the ESR from the manufacturer's data sheet and determine the ΔIL to fit within the acceptable range of ΔVP-P. Especially in the case of electrolytic capacitor, because the decrease in capacitance at low temperatures is significantly large, this will make ΔVP-P increase. When using capacitor at low temperature, this is an important consideration. The shielded type (closed magnetic circuit type) is the recommended type of inductor to be used. Plea se note that magnetic saturation may occur. It is important not to saturate the core in all cases. Precautions must be taken into account on the given provisions of the current rating because it differs on every manufacturer. Please confirm the rated current at maximum ambient temperature of application to the manufacturer.

11.Sep.2018 Rev.001 © 2018 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 www.rohm.com BD8P250MUF-C Selection of Components Externally Connected - continued 2. Selection of Output Capacitor COUT The output capacitor is selected based on the ESR that is required from the equation (a). ΔVP-P can be reduced by using a capacitor with a small ESR. The ceramic capacitor is the best option that meets this requirement. It is because not only does it has a small ESR but the ceramic capacitor also contributes to the size reduction of the applica tion circuit. Please confirm the frequency characteristics of ESR from the datasheet of the manufacturer, and consider a low ESR value for the switching frequency being used. It is necessary to consider the ceramic capacitor because the DC biasing characteristic is important. For the voltage rating of the ceramic capacitor, twice or more than the maximum output voltage is usually required. By selecting a high voltage rating, it is possible to reduce the influence of DC bias characteristics. Moreover, in order to maintain good temperature characteristics, the one with the characteristics of X7R or better is recommended. Because the voltage rating of a large ceramic capacitor is low, the selection becomes difficult for an application with high output voltage. In that case, please connect multiple ceramic capacitors in series or select electrolytic capacitor. Consider having a voltage rating of 1.2 times or more of the output voltage when using electrolytic capacitor. Electrolytic capacitors have a high voltage rating, large capacitance, small amount of DC biasing characteristics, and are generally reasonable. Since the electrolytic capacitor is usually OPEN when it fails, it is effective to use for applications when reliability is required such as automotive. Bu t there are disadvantages such as, ESR is relatively high, and decreases capacitance value at low temperatures. In this case, please take note that ΔV P-P may increase at low temperature conditions. Moreover, consider the lifetime characteristic of this capacitor because it has a possibility to dry up. A tantalum capacitor and a conductive polymer hybrid capacitor have excellent temperature characteristics unlike the electrolytic capacitor. Moreover, since their ESR is smaller than an electrolytic capacitor, the ripple voltage is relatively -small over a wide temperature range. Since these capacitors have almost no DC bias characteristics, design will be easier. Regarding voltage rating, the tantalum capacitor is selected such that its capacitance is twice the value of the output voltage, and for the conductive polymer hybrid capacitor, it is selected such that the voltage rating is 1.2 times the value of the output voltage. The disadvantage of a tantalum capacitor is that it is SHORTED when it is destroyed, an d its breakdown voltage is low. It is not generally selected in an application that reliability is a demand such as in automotive. An electro conductive polymer hybrid capacitor is OPEN when destroyed. Though it is effective for reliability, its disadvantage is that it is generally expensive. To improve the performance of ripple voltage in this condition, following is recommended: 1. Use low ESR capacitor like ceramic or conductive polymer hybrid capacitor. 2. Use a capacitor COUT with a higher capacitance value. These capacitors are rated in ripple current. The RMS values of the ripple current that can be obtained in the following equation must not exceed the ripple current rating. 𝐼𝐶𝑂(𝑅𝑀𝑆) = ∆𝐼𝐿 √12 [A] Where: 𝐼𝐶𝑂(𝑅𝑀𝑆) is the value of the ripple electric current ∆𝐼𝐿 is the peak to peak inductor current In addition, for the total value of capacitance in the output line COUT(Max), choose a capacitance value less than the value obtained by the following equation: 𝐶𝑂𝑈𝑇(𝑀𝑎𝑥) < 𝑡𝑆𝑆(𝑀𝑖𝑛)×(𝐼𝑆𝑊(𝑀𝑖𝑛)−𝐼𝑆𝑊𝑆𝑇𝐴𝑅𝑇(𝑀𝑎𝑥)) 𝑉𝑂𝑈𝑇 [F] Where: 𝐼𝑆𝑊(𝑀𝑖𝑛) is the OCP operation switch current (Min) 𝑡𝑆𝑆(𝑀𝑖𝑛) is the Soft Start Time (Min) 𝐼𝑆𝑊𝑆𝑇𝐴𝑅𝑇(𝑀𝑎𝑥) is the maximum output current during startup 𝑉𝑂𝑈𝑇 is the output voltage Startup failure may happen if the limits from the above-mentioned are exceeded. Especially if the capacitance value is extremely large, over-current protection may be activated by the inrush current at startup preventing the output to turn on. Please confirm this on the actual application. For stable transient response, the loop is dependent to COUT. Please select after confirming the setting of the phase compensation circuit. Also, in case of large changing input voltage and load current, select the capacitance accordingly by verifying that the actual application setup meets the required specification.

11.Sep.2018 Rev.001 © 2018 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 www.rohm.com BD8P250MUF-C Selection of Components Externally Connected - continued 3. Selection of Input Capacitor CIN, CBLK The input capacitor is usually required for two types of decoupling: capacitors CIN and bulk capacitors CBLK. For the decoupling capacitors, two ceramic capacitors are required: CIN1 with a small capacitance and CIN2 with a large capacitance. CIN1 and CIN2 can reduce the switching noise and ripple noise, respectively. The effects of these ceramic capacitors are obtained by placing them as close as possible to the PVIN and VIN pins. For CIN2, it is recommended to use a capacitor with the capacitance value of 2.3 µF or more, also, with the voltage rating that is 1.2 times or more of the maximum input voltage and 2 times or more of the normal input voltage. The capacitor value including device variation, temperature change, DC bias change, and aging change must be larger than minimum value. Also, the IC might not operate properly when the PCB layout or the position of the capacitor is not good. Please check “Notes on the PCB Layout Design” on page 34, 35. The bulk capacitor is optional. The bulk capacitor prevents the decrease in the line voltage and serves as a backup power supply to keep the input voltage constant. A low ESR electrolytic capacitor with large capacitance is suitable for the bulk capacitor. It is necessary to select the best capacitance value for each set of application. In that case, please take note not to exceed the rated ripple current of the capacitor. The RMS value of the input ripple current ICIN(RMS) is obtained in the following equation: 𝐼𝐶𝐼𝑁(𝑅𝑀𝑆) = 𝐼𝑂𝑈𝑇(𝑀𝐴𝑋) × √𝑉𝑂𝑈𝑇×(𝑉𝐼𝑁−𝑉𝑂𝑈𝑇) 𝑉𝐼𝑁 [A] Where: 𝐼𝑂𝑈𝑇(𝑀𝐴𝑋) is the maximum output current. In addition, in automotive and other applications requiring high reliability, it is recommended to connect the capacitors in parallel to accommodate multiple electrolytic capacitors and minimize the chances of drying up. For ceramic capacitors, it is recommended to make two series + two parallel structures to decrease the risk of capacitor destruction due to short circuit conditions. When the impedance on the input side is high for some reason (because the wiring from the power supply to VIN is long, etc.), then high capacitance is needed. In actual conditions, it is necessary to verify that there are no problems like IC turns off, or the output overshoots due to the change in VIN at transient response. 4. Selection of the Bootstrap Capacitor Bootstrap capacitor CBOOT value shall be 0.1 μF. Connect the bootstrap capacitor between SW pin and BOOT pin. Recommended products are described in Application Examples1 on page 27. 5. Selection of the VREG Capacitor. VREG capacitor CREG shall be 1.0 μF(Typ) ceramic capacitor. Connect the VREG capacitor between VREG pin and GND. Recommended products are described in Application Examples1 on page 27.

© 2018 ROHM Co., Ltd. All rights reserved. Figure 68. Automotive Power Supply Line Circuit As a reference, the automotive power supply line circuit example is given in Figure 68. should be placed close to each other. shown in the following table. connected in the opposite direction. Table 5. Reference Parts of Automotive Power Supply Line Circuit Shown below is the list of the recommended parts manufacturers for reference.

Place the input decoupling capacitors of 4.7 µF (CIN2) for the VIN pin (2-pin) and 0.1 µF (CIN1) for the PVIN pin (3-, 4-,

placed closer to the PVIN pin than the capacitor of 4.7 µF (CIN2).

Place the IC, input capacitor, output inductor, and output capacitor on the same surface layer of the board, and

connect the parts on the same layer.

Place the ground plane on the layer nearest to the surface layer on which the IC is placed.
The GND pin (22-pin) is the reference ground and the PGND pin is the power ground. These pins may be connected

ground pattern. Connect the separated power ground to the ground plane using as many vias as possible.

Place the bypass capacitor between the VREG (23-pin) and GND pins at a position as close as possible to the pin.
Place the capacitors connected between the SW pin (12-, 13-, and 14-pin) and the BOOT (15 -pin) at positions as

close as possible to each pin.

To minimize the radiated noise from the switching node, keep the distance from the SW pin to the inductor short, and

do not extend the area of copper foil pattern more than necessary.

Place the output capacitor near the inductor and the power ground.
Place the wire for the feedback line from the output away from the inductor and the switching node. If the wire is

move the feedback line to the back surface through a via, and connect the line to the VOUT pin (20-pin).

ROUT (optional) is for measuring the frequency characteristics of the feedback. By inserting a resistor in R OUT, the

Figure 70. Evaluation Board Layout Example Figure 71. Evaluation Board Layout Example

The ambient temperature Ta is to be 125 °C or less.
The chip junction temperature Tj is to be 150 °C or less.
To obtain Tj from the package surface center temperature Tt in actual use
To obtain Tj from the ambient temperature Ta

Figure 72. SW Waveform

11.Sep.2018 Rev.001 © 2018 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 www.rohm.com BD8P250MUF-C I/O Equivalence Circuits 1.EN, 17.SSCG, 24.MODE 19. PGOOD 18. CTLOUT *Resistance value is Typ. GND SSCG/ EN/ MODE 10kΩ GND PGOOD GND 100Ω BOOT VREG PGND SW PVIN GND VREG VREG VIN VCC_EX VOUT GND GND GNDGND GND 100kΩ 9MΩ 3MΩ VREG CTLOUT GND GND

11.Sep.2018 Rev.001 © 2018 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 www.rohm.com BD8P250MUF-C Operational Notes 1. Reverse Connection of Power Supply Connecting the power supply in reverse polarity can damage the IC. Take precautions against reverse polarity when connecting the power supply, such as mounting an external diode between the power supply and the IC’s power supply pins. 2. Power Supply Lines Design the PCB layout pattern to provide low impedance supply lines. Furthermore, connect a capacitor to ground at all power supply pins. Consider the effect of temperature and aging on the capacitance value when using electrolytic capacitors. 3. Ground Voltage Ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition. However, pins that drive inductive loads (e.g. motor driver outputs, DC -DC converter outputs) may inevitably go below ground due to back EMF or electromotive force. In such cases, the user should make sure that such voltages going below ground will not cause the IC and the system to malfunction by examining carefully all relevant factors and conditions such as motor characteristics, supply voltage, operating frequency and PCB wiring to name a few. 4. Ground Wiring Pattern When using both small-signal and large-current ground traces, the two ground traces should be routed separately but connected to a single ground at the reference point of the application board to avoid fluctuations in the small -signal ground caused by large currents. Also ensure that the ground traces of external components do not cause variations on the ground voltage. The ground lines must be as short and thick as possible to reduce line impedance. 5. Recommended Operating Conditions The function and operation of the IC are guaranteed within the range s pecified by the recommended operating conditions. The characteristic values are guaranteed only under the conditions of each item specified by the electrical characteristics. 6. Inrush Current When power is first supplied to the IC, it is possible that the internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequence and delays, especially if the IC has more than one power supply. Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of connections. 7. Testing on Application Boards When testing the IC on an application board, connecting a capacitor directly to a low -impedance output pin may subject the IC to stress. Always discharge capacitors com pletely after each process or step. The IC’s power supply should always be turned off completely before connecting or removing it from the test setup during the inspection process. To prevent damage from static discharge, ground the IC during assembly and use similar precautions during transport and storage. 8. Inter-pin Short and Mounting Errors Ensure that the direction and position are correct when mounting the IC on the PCB. Incorrect mounting may result in damaging the IC. Avoid nearby pins being shorted to each other especially to ground, power supply and output pin. Inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment) and unintentional solder bridge deposited in between pins during assembly to name a few. 9. Unused Input Pins Input pins of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance and extremely low capacitance. If left unconnected, the electric field from the outside can easily charge it. The small charge acquired in this way is enough to produce a significant effect on the conduction through the transistor and cause unexpected operation of the IC. So unless otherwise specified, unused input pins should be connected to the power supply or ground line.

Regarding the Input Pin of the IC

When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode. When GND > Pin B, the P-N junction operates as a parasitic transistor. Figure 73. Example of Monolithic IC Structure temperature and the decrease in nominal capacitance due to DC bias and others.

Thermal Shutdown Circuit (TSD)

falls below the TSD threshold, the circuits are automatically restored to normal operation.

Over Current Protection Circuit (OCP)

not be used in applications characterized by continuous operation or transitioning of the protection circuit.

Ordering Information

B D 8 P 2 5 0 M U F - CE 2 Part Number Package MUF: VQFN024FV4040 Product class C for Automotive applications Packaging and forming specification E2: Embossed tape and reel Marking Diagram VQFN24FV4040 (TOP VIEW)

8 P 2 5 0

Revision History

11.Sep.2018 001 New Release

Notice-PAA-E Rev.003 © 2015 ROHM Co., Ltd. All rights reserved. Notice Precaution on using ROHM Products 1. If you intend to use our Products in devices requiring extremely high reliability ( such as medical equipment (Note 1), aircraft/spacecraft, nuclear power controllers, etc.) and whose malfunction or failure may cause loss of human life , bodily injury or serious damage to property ( “Specific Applications ”), please consult with the ROHM sales representative in advance. Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific Applications. (Note1) Medical Equipment Classification of the Specific Applications JAPAN USA EU CHINA CLASSⅢ CLASSⅢ CLASSⅡb CLASSⅢ CLASSⅣ CLASSⅢ 2. ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor products can fail or malfunction at a cert ain rate. Please be sure to implement, at your own responsibilities, adequate safety measures including but not limited to fail -safe design against the physical injury, damage to any property, which a failure or malfunction of our Products may cause. The following are examples of safety measures: [a] Installation of protection circuits or other protective devices to improve system safety [b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure 3. Our Products are not designed under any special or extraordinary environments or conditions, as exemplified below . Accordingly, ROHM shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any special or extraordinary environments or conditions . If you intend to use our Products under any special or extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be necessary: [a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents [b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust [c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves [e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items [f] Sealing or coating our Products with resin or other coating materials [g] Use of our Products without cleaning residue of flux (even if you use no -clean type fluxes, cle aning residue of flux is recommended); or Washing our Products by using water or water -soluble cleaning agents for cleaning residue after soldering [h] Use of the Products in places subject to dew condensation 4. The Products are not subject to radiation-proof design. 5. Please verify and confirm characteristics of the final or mounted products in using the Products. 6. In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied, confirmation of performance characteristics after on -board mounting is strongly recommended. Avoid applying power exceeding normal rated power; exceeding the power rating under steady -state loading condition may negatively affect product performance and reliability. 7. De-rate Power Dissipation d epending on ambient temperature. When used in sealed area, confirm that it is the use in the range that does not exceed the maximum junction temperature. 8. Confirm that operation temperature is within the specified range described in the product specification. 9. ROHM shall not be in any way responsible or liable for failure induced under de viant condition from what is defined in this document. Precaution for Mounting / Circuit board design 1. When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product performance and reliability. 2. In principle, the reflow soldering method must be used on a surface -mount products, the flow soldering method must be used on a through hole mount products. If the flow soldering method is preferred on a surface -mount products, please consult with the ROHM representative in advance. For details, please refer to ROHM Mounting specification

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Minimum Package Quantity 2500 Packing Type Taping Constitution Materials List inquiry RoHS Yes BD8P250MUF-C - Web Page

Product Information

BD8P250MUF-C specifications and overview.

Summary

2.7 V to 36 V Input, 2 A Single Buck DC/DC Converter with Boost Function For Automotive

Description

2.7 V to 36 V Input, 2 A Single Buck DC/DC Converter with Boost Function For Automotive

Source title BD8P250MUF-C Datasheet(PDF) - Rohm

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