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ROHM BD9853AFV datasheet manual

Summary

Rohm BD9853AFV 2-channel synchronous DC/DC step-down controller datasheet. Operates up to 2MHz for compact designs. Features FET direct drive, adjustable frequency, UVLO, TSD, SCP, and independent ON/OFF per channel with soft start. SSOP-B16 package. For power engineers designing regulators for TVs, PCs, and portable devices.

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Large Current External FET Controller Type Switching Regulators

Single/Dual-output High-frequency Step-down Switching Regulator(Controller type)

BD9853AFV No.09028EAT05

●Description The BD9853AFV is a 2-ch synchronous DC/DC controller that can operate at a maximum switching frequency of 2MHz, enabling the use of a smaller external coil than conventional lower-frequency switching regulators. This makes the BD9853AFV a suitable choice for downsizing applications.

●Features 1) Synchronous Switching Regulator Controller 2channels 2) FET(Pch/Nch) Direct Drive 3) Adjustable Oscillator Frequency with External Resistor (Max. 2MHz) 4) Under Voltage Lockout Function (UVLO) 5) Thermal Shut Down Function (TSD) 6) Short Circuit Protection (SCP) 7) Independent ON/OFF Function in Each Channel with Soft Start Pin 8) SSOP-B16 Package SSOPB16

●Applications TVSTB, PC, Portable CD・DVD,DVC etc.

●Absolute Maximum Ratings (Ta = 25℃)

Parameter Symbol Limits Unit

Supply Voltage (VCC-GND) Vcc 18 V VREGA-GND Voltage VREGA 7 V VCC-VREGB Voltage VREGB 7 V Power Dissipation Pd 562(*1) m W Operating Temperature Range Topr -40 to +85 ℃ Junction Temperature Tjmax +150 ℃ Storage Temperature Range Tstg -55 to +150 ℃ * Reduced by 4.49m W for each increase in Ta of 1℃ over 25℃ (When mounted on a board 70×70×1.6tmm grass-epoxy PCB)

●Recommended Operating Conditions

Limits

Parameter Symbol Unit

Min. Typ. Max.

Supply Voltage Vcc 4.5 12 16 V Oscillator Frequency fosc 100 1000 2000 KHz

www.rohm.com 2009.05 - Rev.A

© 2009 ROHM Co., Ltd. All rights reserved.

Page Summary Contents For ROHM BD9853AFV datasheet manual

Page 1 Large Current External FET Controller Type Switching Regulators Single/Dual-output High-frequency Step-down Switching Regulator(Controller type) BD9853AFV No.09028EAT05 ●Description The BD9853AFV is a...
Page 2 BD9853AFV Technical Note ●Electrical Characteristics (Unless otherwise specified Ta=25℃,Vcc=12V,fosc=1000k Hz,STB=3V) Limits Parameter Symbol Unit Conditions Min. Typ. Max. 【Whole Device】 Standby Curr...
Page 3 BD9853AFV Technical Note ●Electrical Characteristics (Unless otherwise specified, Ta=25℃,Vcc=12V,fosc=1000k Hz,STB=3V) Limits Parameter Symbol Unit Conditions Min. Typ. Max. 【FET Driver】 Ron P 1.6 3.2...
Page 4 BD9853AFV Technical Note [m IN :IO [m ●Characteristic Data Phase -20 Gain 0.01 0.1 0.2 0.4 0.6 0.8 1.2 1.4 1.6 1.8 2.2 2.4 2.6 2.8 3.2 3.4 3.6 3.8 IN [d ]、 [d eg IN :IO [m FB VOLTAGE:VFB[V] FB VOLTAGE...
Page 5 BD9853AFV Technical Note ●Block Diagram VCC both channel ON/OFF 5V REGA FB1 REGB VCC-5V VOUT1 SOFT1 TSD VREF VCC VCC INV1 Pch OUT1H VOUT1 ⊿ t REGA (Push-Pull) OUT1L SCP/SOFT1 VOUT2 0.56V SOFT2 OUT2H 0...
Page 6 BD9853AFV Technical Note ●Pin Configuration Fig. 10 ●Pin Description Pin Number Pin Name Pin Descriptions 1 VCC Input Supply Voltage 2 OUT1H High Side (Main) FET Driver Output Pin (CH1) 3 OUT1L Low Si...
Page 7 BD9853AFV Technical Note ●Block functional descriptions ・Triangular wave oscillator Connecting the resistor that sets the triangular wave oscillation frequency at the RT terminal generates the triangu...
Page 8 BD9853AFV Technical Note ●Timing Chart STB STB ON STB OFF Output OFF at SCP protection OFF SCP/SOFT<0.3V Vo1(solid line) INV1 (dotted line) 0.8V External GND short 1.3V (independent control) SCP/SO...
Page 9 BD9853AFV Technical Note ●Application component selection and settings sc ill at in re y( z) Determining output voltage Output voltage is determined by dividing the resistance of the external resistor...
Page 10 BD9853AFV Technical Note Selecting the synchronous diode An extremely low forward voltage Schottky barrier diode should be employed as the synchronous diode. Selection of the specific diode to be used...
Page 11 BD9853AFV Technical Note Setting the Short Circuit Protection (SCP) delay time When the soft start is complete for each channel, the output voltage stabilizes at the set value 1.35V(typ) for the SCP/S...
Page 12 BD9853AFV Technical Note ●I/O Equivalent Circuit OUT1H(2),OUT2H(15) OUT1L(3),OUT2L(14) REGA(4) Max ratings:7V(from VCC or REGB) Max ratings:7V Max ratings:7V VCCREGA VCC OUT1L OUT1H OUT2L OUT2H RT(5) ...
Page 13 BD9853AFV Technical Note ●Recommended Board Patterns P MOS C IN GND(IC) GND(others) N MOS C OUT There are two current loops at the behavior of switching regulator. When laying a pattern on the board, ...
Page 14 BD9853AFV Technical Note ●Notes for use 1) Absolute maximum ratings Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range may result in IC dete...
Page 15 BD9853AFV Technical Note 12) IC pin input This monolithic IC contains P+ isolation and PCB layers between adjacent elements in order to keep them isolated. P/N junctions are formed at the intersection...
Page 16 BD9853AFV Technical Note ●Ordering part number Part No. Part No. Package Packaging and forming specification FV: SSOP-B16 E2: Embossed tape and reel .3 in SSOP-B16 <Tape and Reel information> Em...
Page 17 Notice No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM Co.,Ltd. The content specified herein is subject to change for improvement without not...

Manual Details

Brand ROHM
Pages 17
File Size 466.50 KB
Published June 17, 2026
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Frequently Asked Questions

What is the maximum switching frequency of the BD9853AFV?

The maximum switching frequency is 2MHz, adjustable via an external resistor.

What is the recommended supply voltage range for this regulator?

The recommended supply voltage range is 4.5V to 16V, with a typical value of 12V.

What safety protection features does the BD9853AFV include?

It includes Under Voltage Lockout (UVLO), Thermal Shut Down (TSD), and Short Circuit Protection (SCP).

Can each channel of the regulator be turned on or off independently?

Yes, each channel has an independent ON/OFF function via the soft start pin.