Rohm BD9673EFJ Technical Note
Summary
This comprehensive document details the BD9673EFJ, a highly efficient step-down switching regulator featuring an internal N-channel MOSFET. Engineered for creating stable low-voltage DC outputs (e.g., 1.2V to 5V) from common mains supplies like 12V or 24V. The manual provides detailed technical specifications, operational characteristics at 300kHz, and system schematics for integrating this regulator into your power design. It is essential reading for electronics engineers developing complex equipment such as household appliances, audiovisual systems, and office automation gear.
Page 1 Text Content
Single-chip Type with Built-in FET Switching Regulators
Flexible Step-down Switching Regulator with Built-in Power MOSFET
BD9673EFJ No.12027ECT57
●Description Output 1.5A and below High Efficiency Rate Step-down Switching Regulator Power MOSFET Internal Type BD9673EFJ mainly used as secondary side Power supply, for example from fixed Power supply of 12V, 24V etc, Step-down Output of 1.2V/1.8V/3.3V/5V, etc, can be produced. This IC has external Coil/Capacitor down-sizing through 300 k Hz Frequency operation, inside Nch-FET SW for 45V “withstand-pressure” commutation and also, high speed load response through Current Mode Control is a simple external setting phase compensation system, through a wide range external constant, a compact Power supply can be produced easily.
●Features 1) Internal 200 mΩ Nch MOSFET 2) Output Current 1.5A 3) Oscillation Frequency 300k Hz 4) Synchronizes to External Clock ( 200k Hz～500k Hz ) 5) Feedback Voltage 1.0V±1.0% 6) Internal Soft Start Function 7) Internal Over Current Protect Circuit, Low Input Error Prevention Circuit, Heat Protect Circuit 8) ON/OFF Control through EN Pin (Standby Current 0 A Typ.) 9) Package: HTSOP-J8 Package
●Applications For Household machines in general that have 12V/24V Lines, etc.
●Absolute Maximum Rating
Parameter Symbol Ratings Unit
VCC-GND Supply Voltage VCC 45 V BST-GND Voltage VBST 50 V BST-Lx Voltage ⊿VBST 7 V EN-GND Voltage VEN 45 V Lx-GND Voltage VLX 45 V FB-GND Voltage VFB 7 V VC-GND Voltage VC 7 V SYNC-GND Voltage SYNC 7 V High-side FET Drain Current IDH 2.0 A Power Dissipation Pd 3.76(*1) W Operating Temperature Topr -40～+105 ℃ Storage Temperature Tstg -55～+150 ℃ Junction Temperature Tjmax +150 ℃ (*1)During mounting of 70×70×1.6t mm 4layer board (Copper area:70mm×70mm).Reduce by 30.08m W for every 1℃ increase. (Above 25℃)
●Operating Conditions (Ta=25℃)
Ratings
Parameter Symbol Unit
Min. Typ. Max.
Power Supply Voltage VCC 7 － 42 V Output Voltage VOUT 1.0(*2) － VCC×0.7 (*2)Restricted by minimum on pulse typ. 200ns
www.rohm.com 2012.02 - Rev.C
© 2012 ROHM Co., Ltd. All rights reserved.
Page Summary Contents For Rohm BD9673EFJ Technical Note
Manual Details
| Brand | ROHM |
|---|---|
| Pages | 19 |
| File Size | 662.27 KB |
| Published | June 04, 2026 |
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Frequently Asked Questions
What is the maximum supply voltage range (VCC)?
The nominal VCC rating is 45V, but the operating condition supports 7V to 42V.
Does this regulator have built-in protection features?
Yes, it includes Over Current Protection, Low Input Error Prevention Circuit, and Heat Protect Circuit.
How can I control the device's power state?
The EN Pin allows for ON/OFF control, ensuring a low standby current of 0 A Typ.
What is the oscillation frequency range?
It operates at 300kHz by default but synchronizes externally between 200kHz and 500kHz.