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ROHM Semiconductor
3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive

3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive

Product catalog summary

General Description: The BD9P2x5MUF-C Series is a current mode synchronous buck DC/DC converter designed for automotive applications, integrating POWER MOSFETs and featuring Nano Pulse Control™ technology.

Features: Key features include AEC-Q100 qualification, a minimum ON pulse of 50 ns, soft start function, current mode control, reset function, light load mode, forced PWM mode, phase compensation, selectable spread spectrum switching, external synchronization, over current protection, under voltage lockout, thermal shutdown, output over voltage protection, and short circuit protection.

Applications: These converters are suitable for automotive and consumer power supplies.

Key Specifications: The input voltage range is 3.5 V to 40 V, with an output voltage range of 0.8 V to 8.5 V for BD9P205MUF-C, 3.3 V for BD9P235MUF-C, and 5.0 V for BD9P255MUF-C. The output current is up to 2.0 A, with a switching frequency of 2.2 MHz and an output voltage accuracy of ±1.75% over a temperature range of -40 °C to +125 °C.

Package: The package dimensions are 4.0 mm x 4.0 mm x 1.0 mm.

Typical Application Circuits: The document provides application circuits with and without discharge functions for different models in the series.

Pin Configuration and Description: Detailed pin configurations and descriptions are provided for each model, highlighting the functions of each pin, such as power supply inputs, ground pins, switching node pins, and various control and protection pins.

Block Diagram: The block diagrams illustrate the internal structure and functions of the converters, including power supply circuits, thermal shutdown, reference voltage generation, power on reset, under voltage lockout, mode detection, clock generation, over voltage protection, short circuit protection, soft start, error amplifiers, current sensing, and more.

Absolute Maximum Ratings: The document specifies the maximum ratings for input voltage, enable voltage, bootstrap voltage, and other critical parameters, along with storage and junction temperature limits.

Thermal Resistance: The document specifies thermal resistance parameters for the VQFN20FV4040 package, including junction-to-ambient (θJA) and junction-to-top (ΨJT) values, based on different PCB configurations. The typical thermal resistance is 120.0 °C/W for a single-layer board and 38.7 °C/W for a four-layer board with thermal vias.

Recommended Operating Conditions: The input voltage range is 3.5 to 40 V, with an operating temperature range from -40 to +125 °C. Output voltages vary by model: BD9P205MUF-C (0.8 to 8.5 V), BD9P235MUF-C (3.3 V), and BD9P255MUF-C (5.0 V). The output current is up to 2 A.

Electrical Characteristics: The document details various electrical parameters, including shutdown current, quiescent current, and power-on reset thresholds. It also covers switching frequency, feedback reference voltage, and overcurrent protection thresholds.

Typical Performance Curves: Graphs illustrate relationships between parameters such as shutdown current vs. input voltage, feedback reference voltage vs. temperature, and switching frequency vs. temperature.

Function Explanation: The document introduces Nano Pulse ControlTM technology, which allows stable voltage control with narrow SW ON times, enabling direct conversion from high input to low output voltages.

Overview: The BD9P2x5MUF-C is a synchronous DC/DC converter with integrated POWER MOSFETs, designed for high transient response using current mode Pulse Width Modulation (PWM) control. It operates in PWM mode under heavy loads and switches to Light Load Mode (LLM) for efficiency under lighter loads.

Light Load Mode and Forced PWM Mode: The converter switches to LLM when the output load drops below 400 mA, entering a SLEEP state to reduce circuit current. Forced PWM mode can be activated to maintain a fixed frequency and reduce output ripple, especially useful for avoiding EMI issues in LLM.

Enable Control: The device can be shut down via the EN pin. When enabled, it activates the internal circuit and initiates a soft start. The discharge function is available in specific models, allowing output voltage discharge when the EN pin is low.

Reset Function: The reset function monitors the FB pin voltage, activating when the output voltage reaches specific thresholds. It provides protection against over-voltage by controlling the RESET pin state.

External Synchronization: The device can synchronize its switching frequency with an external clock signal within a specified range, enhancing flexibility in various applications.

Frequency Division Function: This function manages the ON time of the High Side FET, ensuring efficient operation even when input and output voltages are close, by skipping OFF pulses.

Spread Spectrum Function: Activating this function reduces EMI noise by varying the switching frequency with a triangular wave pattern.

VCC_EX Function: This function allows the internal supply to be powered from the output voltage, improving efficiency. It includes protection mechanisms to prevent excessive voltage.

Protection Functions: The device includes Over Current Protection (OCP) and Short Circuit Protection (SCP) to prevent damage from excessive current or short circuits. Power On Reset (POR) and Under Voltage Lockout (UVLO) ensure stable operation by monitoring supply voltages.

Protection Functions:

Thermal Shutdown (TSD): The IC includes a thermal shutdown circuit that activates at 175°C to prevent heat damage, turning off the POWER MOSFETs. It restarts at 150°C with a soft start, requiring an input voltage of 4.0 V or more.
Over Voltage Protection (OVP): Monitors the FB pin to prevent output voltage increase due to external current. If FB voltage exceeds 107.3% of its setting, the IC sinks current from VOUT. The OVP function is released when FB voltage falls below 104.7%.

Component Selection:

Inductor (L1): The inductor value affects the ripple current and output voltage ripple. The recommended range varies based on output current and voltage.
Output Capacitor (COUT): Selected based on ESR requirements. Ceramic capacitors are preferred for their low ESR and size benefits. The capacitance should be adjusted based on output voltage and other factors.
Input Capacitor (CIN, CBLK): Ceramic capacitors with a total value of 2.3 µF or more are recommended for ripple noise reduction. Bulk capacitors are optional but help maintain input voltage stability.
Output Voltage Setting Resistor (RFB1, RFB2): These resistors set the output voltage, with a reference voltage of 0.8 V. The combined resistance should be 100 kΩ or less to avoid phase shift issues.

Application Circuit: The document provides a sample application circuit and specifies necessary parameters such as input voltage (3.5 V to 40 V), output voltage (5.0 V), and switching frequency (2.2 MHz).

Switching Frequency and Voltage Ripple:

The document outlines equations to maintain stable switching frequency and minimize output voltage ripple. It emphasizes the importance of satisfying specific conditions to ensure optimal performance.

Component Selection:

Bootstrap Capacitor (CBST): Use a 0.1 μF ceramic capacitor between the BST and SW pins.
VREG Capacitor (CREG): Use a 1.0 μF ceramic capacitor between the VREG pin and GND.

Application Examples:

The document provides three application examples with detailed parts lists and reference circuits. Each example includes specifications for input and output voltages, current, and temperature ranges.

Example 1: Output Voltage 6.0 V
Example 2: Output Voltage 3.3 V
Example 3: Output Voltage 5.0 V

Graphs and Figures:

The document includes various graphs illustrating efficiency, input current, frequency characteristics, and response times under different conditions. These visual aids help in understanding the performance of the converters under specified conditions.

Automotive Power Supply Line Circuit:

An example of an automotive power supply line circuit is provided, featuring a π-type filter, which is a third-order LC filter commonly used in combination with other components for enhanced performance.

Decoupling Capacitors and EMI Filtering: Decoupling capacitors are essential for high-frequency applications due to their large attenuation characteristics, making them effective as EMI filters. For optimal performance, devices used in π-type filters should be placed in close proximity to each other.

Automotive Power Supply Protection: Transient Voltage Suppressors (TVS) are recommended for primary protection of automotive power supply lines, as they can withstand high energy load dump surges, unlike general Zener diodes. A reverse polarity protection diode is also necessary to prevent damage if the power supply is connected in reverse.

Reference Parts for Automotive Power Supply: The document provides a table listing recommended parts and manufacturers for automotive power supply circuits, including inductors, capacitors, and diodes from manufacturers like TDK, Coilcraft, and Vishay.

PCB Layout Design for DC/DC Converters: Proper PCB layout design is crucial for DC/DC converter power supply ICs to avoid issues caused by power supply circuits. Key recommendations include minimizing loop areas to reduce noise, placing components on the same board side, and ensuring short connections between critical components.

Power Dissipation and Thermal Design: Thermal design must ensure the ambient temperature does not exceed 125°C and the chip junction temperature remains below 150°C. The document provides formulas to calculate the chip junction temperature and heat loss, emphasizing the importance of operating within specified thermal conditions.

Operational Notes: Several operational precautions are outlined, including reverse power supply connection protection, low impedance supply line design, and ensuring no pins fall below ground voltage. The document also advises on ground wiring patterns, handling inrush current, and testing on application boards.

Protection Circuits: The IC includes a thermal shutdown circuit to prevent heat damage and an overcurrent protection circuit to safeguard against load shorts. These circuits are designed for emergency protection and should not be relied upon for regular operation.

Product Overview: The document details the BD9P2x5MUF-C series of voltage regulators by ROHM Co., Ltd., designed for automotive applications. The series includes adjustable and fixed output voltage options (3.3V and 5.0V) and is packaged in VQFN20FV4040.

Specifications: The series includes three main part numbers: BD9P205MUF-CE2 (adjustable), BD9P235MUF-CE2 (3.3V), and BD9P255MUF-CE2 (5.0V). Each part number has a specific marking for identification.

Packaging: Products are supplied in embossed tape and reel packaging, suitable for automated assembly processes.

Precautions: The document outlines several precautions for using ROHM products, emphasizing the need for consultation when used in high-reliability applications such as medical or aerospace. It also highlights the importance of implementing safety measures like protection circuits and redundant systems.

Environmental Considerations: ROHM products are not designed for special environments such as exposure to liquids, corrosive gases, or extreme temperatures. Users must verify product performance under such conditions independently.

Mounting and Circuit Design: Recommendations include using reflow soldering for surface-mount products and consulting ROHM for alternative methods. The document advises on managing electrostatic discharge and storage conditions to maintain product integrity.

Legal and Compliance Notices: The document includes disclaimers regarding intellectual property rights, export control, and the prohibition of military use. It also states that the information is subject to change and should be verified with ROHM representatives.

Catalog excerpts

3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive-1

Nano Pulse ControlTM 3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive BD9P2x5MUF-C Series General Description BD9P2x5MUF-C Series are current mode synchronous buck DC/DC converter integrating POWER MOSFETs.  Input Voltage Range: 3.5 V to 40 V (Initial startup is 4.0 V or more)  Output Voltage Range BD9P205MUF-C: 0.8 V to 8.5 V BD9P235MUF-C: 3.3 V (Typ) BD9P255MUF-C: 5.0 V (Typ)  Output Current: OCP_SEL = H 1.5 A (Max) OCP_SEL = L 2.0 A (Max)  Switching Frequency: 2.2 MHz (Typ)  Output Voltage Accuracy: ±1.75 % (-40 °C to +125 °C)  Shutdown Current: 2.1 μA (Typ)  Operating Temperature Range: -40 °C to +125 °C Nano Pulse ControlTM AEC-Q100 Qualified(Note 1) Minimum ON Pulse 50 ns (Max) Synchronous Buck DC/DC Converter Integrating POWER MOSFETs Soft Start Function Current Mode Control Reset Function Quiescent Current 10 μA (Typ) with 12 V Input to 5.0 V Output Light Load Mode (LLM) Forced Pulse Wide Modulation (PWM) Mode Phase Compensation Included Selectable Spread Spectrum Switching External Synchronization Function Selectable Over Current Protection (OCP) Input Under Voltage Lockout (UVLO) Protection Thermal Shut Down (TSD) Protection Output Over Voltage Protection (OVP) Short Circuit Protection (SCP) Enlarged View Automotive Powered Supplies Consumer Powered Supplies VQFN20FV4040 Wettable Flank Package Typical Application Circuit CBST Figure 1. Application Circuit with Discharge Function (BD9P235MUF-C, BD9P255MUF-C) Nano Pulse ControlTM is a trademark or a registered trademark of ROHM Co., Ltd. 〇Product structure : Silicon integrated circuit . www.rohm.com © 2019 ROHM Co., Ltd. All rights reserved. TSZ22111 • 14 • 001 〇This product has no designed protection against ra

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3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive-2

BD9P2x5MUF-C Series Typical Application Circuit - continued CBST RRST VMODE Figure 2. Application Circuit without Discharge Function (BD9P235MUF-C, BD9P255MUF-C) VMODE VSSCG Figure 3. Application Circuit (BD9P205MUF-C) Note: The difference between BD9P205MUF-C, BD9P235MUF-C and BD9P255MUF-C The VOUT_DIS pin and discharge function are not available with BD9P205MUF-C. The FB pin is assigned on the BD9P205MUF-C and the resistors dividing the output voltage are connected. The output voltage is defined by the resistors (RFB1, RFB2). The VOUT discharge function are available with BD9P235MUF-C and BD9P255MUF-C,...

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3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive-3

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3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive-4

www.rohm.com © 2019 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 Function Power supply input pins that are used for the output stage of the switching regulator. Connect input ceramic capacitors referring Page 33 between the PGND pins and these pins. This pin is not connected to the chip. Use this as open. If this pin is used other than open and adjacent pins are expected to be shorted, please confirm if there is any problem with the actual application. Ground pins for the output stage of the switching regulator. Switching node pins. These pins are connected to the source of the internal...

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3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive-5

BD9P2x5MUF-C Series Block Diagram VREG tsdout OCP_SEL VREF HOCP Comp Soft Start Control Logic sleep VREF Current Sense Reset PGND VREF VOUT_SNS EN porout uvloout tsdout Figure 7. Block Diagram (BD9P205MUF-C) www.rohm.com © 2019 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001

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3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive-6

BD9P2x5MUF-C Series Block Diagram - continued VREG tsdout OCP_SEL VREF HOCP Comp Soft Start Control Logic sleep VREF Current Sense VREF Reset PGND VREF EN porout uvloout tsdout Figure 8. Block Diagram (BD9P235MUF-C, BD9P255MUF-C) www.rohm.com © 2019 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001

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3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive-7

BD9P2x5MUF-C Series Description of Blocks - PreReg This block is the internal power supply for TSD and VREF circuits. VREG This block is the internal power supply circuit. It outputs 3.3 V (Typ) and is the power supply to the control circuit and Driver. TSD This is the thermal shutdown circuit. It will shut down the device when the junction temperature (Tj) reaches to 175 °C (Typ) or more. When the Tj falls below the TSD threshold with hysteresis of 25 °C (Typ), the circuits are automatically restored to normal operation. VREF The VREF block generates the internal reference voltage. POR The POR...

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3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive-8

BD9P2x5MUF-C Series Description of Blocks - continued - PWM Comp This block compares the output voltage of the GmAmp2 (Vc) and the saw tooth waveform (Vr) to control the switching duty. Ramp This block generates the saw tooth waveform (Vr) from the clock signal generated by OSC. Control Logic This block controls switching operation and protection functions. Driver This circuit drives the gates of the output FETs. Sleep Comp If output/feedback voltage becomes 101.3 % (Typ) or more, this block puts the device into SLEEP state. This state is released when output/feedback voltage becomes 101.0 %...

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3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive-9

BD9P2x5MUF-C Series Absolute Maximum Ratings Parameter VVIN, VPVIN Input Voltage VOUT_DIS Voltage ΔVBST VFB, VRESET, VMODE, VSSCG VOCP_SEL VVOUT_DIS VOUT_SNS Voltage BST Voltage Voltage from SW to BST FB, RESET, MODE, SSCG, OCP_SEL Voltage VREG Voltage Storage Temperature Range Maximum Junction Temperature Human Body Model (HBM)(Note 1) VCC_EX Voltage Caution 1: Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit between pins and the internal circuitry. Therefore, it is important to consider circuit protection...

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3.5 V to 40 V Input, 2 A Single 2.2 MHz Buck DC/DC Converter For Automotive-10

BD9P2x5MUF-C Series Recommended Operating Conditions Parameter VVIN, VPVIN Input Voltage SW Minimum OFF Time (VREG = 3.3 V) SW Minimum OFF Time (VREG = 5.0 V) Operating Temperature Output Current Input Capacitor (VIN Continuous Condition) (Note 3) VREG Capacitor(Note 3) (Note 1) Although the output voltage is configurable at 0.8 V and higher, it may be limited by the SW min ON pulse width. For the same reason, although the output voltage is configurable at 8.5 V and more, it may be limited by the SW minimum OFF pulse width. For the configurable range, please refer to the Output Voltage Setting...

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