Datasheet 4.5V to 28V Input, 8.0A Integrated MOSFET Single Synchronous Bu ck DC/DC Converter BD9F800MUX-Z General Description Key Specifications BD9F800MUX-Z is a synchronous buck DC/DC converter Input Voltage Range: 4.5V to 28 V with built-in low on-resistance power MOSFETs. It is Output Voltage Setting Range: 0.765V to 13.5V capable of providing current of up to 8 A. External phase Output Current: 8 A (Max) compensation circuit is not necessary for it is a constant Switching Frequency: 300kHz or 600kHz (Typ) on-time control DC/DC converter with high speed High Side MOSFET On-Resistance: 23 m (Typ) response. Low Side MOSFET On-Resistance: 11 m (Typ) Shutdown Current: 2 A (Typ) Features Synchronous Single DC/DC Converter Package W (Typ) D (Typ) H (Max) Constant On-time Control VQFN11X3535A 3.50mm 3.50mm 0.60mm Over Current Protection Short Circuit Protection Thermal Shutdown Protection Under Voltage Lockout Protection Power Good Output VQFN11X3535A Package Applications Step-down Power Supply for DSPs, Microprocessors, etc. Set-top Box LCD TVs DVD / Blu-ray Player / Recorder Entertainment Devices VQFN11X3535A Typical Application Circuit BD9F800MUX-Z VIN V IN Enable EN BOOT CIN CBOOT PGND V OUT SW L FREQ VOUT R1 RFREQ VREG FB COUT CVREG PGD GND R2 Figure 1. Typical Application Circuit Product structure: Silicon monolithic integrated circuit This product has no designed protection against radioactive rays. www.rohm.com TSZ02201-0F3F0AC00090-1-2 2017 ROHM Co., Ltd. All rights reserved. 1/47 TSZ22111 14 001 27.Dec.2018 Rev.003 BD9F800MUX-Z Pin Configuration (TOP VIEW) 7. GND 11. EN 8. VIN 9. SW 10. PGND Figure 2. Pin Configuration Pin Descriptions Terminal Symbol Function No. Bootstrap terminal. 1 BOOT Connect a ceramic capacitor of 0.1F between BOOT and SW terminal. The voltage of this capacitor is the gate drive voltage of the High-Side MOSFET. Power Good terminal. It is necessary to connect a pull-up resistor due to an open drain 2 PGD output. See page 19 for how to specify the resistance. When the FB terminal voltage is within 7% of 0.765V (Typ), the internal Nch MOSFET turns off and the output turns High. Output voltage sense terminal. 3 VOUT Connect a 10 resistor in series when output voltage setting is more than 3.3V. Switching frequency setting terminal. Switching frequency is set to 300kHz when this terminal is set to Low (0.8V or lower). Setting 4 FREQ this terminal to High (2.2V or higher) will make switching frequency set to 600kHz. This terminal needs to be pulled down to ground or pulled up to VREG by 10k. An inverting input node for the error amplifier and main comparator. 5 FB To calculate for the resistance value of the output voltage setting, refer to page 39. Internal power supply voltage terminal. 6 VREG A voltage of 5.25V (Typ) is outputted if there is more than 2.3V for EN terminal. Connect a ceramic capacitor of 2.2F to ground. 7 GND Ground terminal for the control circuit. Power supply terminal for the switching regulator. 8 VIN Connecting 20F(10F2) and 0.1F ceramic capacitor to ground is recommended. Switch terminal. The SW terminal is connected to the source of the High-Side MOSFET and drain of the Low-Side MOSFET. Connect a bootstrap capacitor of 0.1F between BOOT and 9 SW SW terminal. Also, connect an inductor considering the direct current superimposition characteristic. 10 PGND Ground terminal for the output stage of the switching regulator. Enable terminal. Turning this terminal signal Low (0.7V or lower) forces the device to enter in shutdown mode. 11 EN Turning this terminal signal High (2.3V or higher) enables the device. This terminal must be properly terminated. www.rohm.com TSZ02201-0F3F0AC00090-1-2 2017 ROHM Co., Ltd. All rights reserved. 2/47 TSZ22111 15 001 27.Dec.2018 Rev.003 27.Dec.2018 Rev.003 6. VREG 5. FB 4. FREQ 3. VOUT 2. PGD 1. BOOT