Datasheet Dual Synchronous Buck Converter BD93291EFJ Description The BD93291EFJ is a dual synchronous buck converter. Features It integrates wide input voltage range (8.0V to 26V) synchronous Dual Synchronous Buck Converter in small package. buck converter and low input voltage (Vout1 : 5.0V) standby mode ( Istandby = 0uA ) synchronous buck converter. High Voltage Synchronous Buck Converter(Vout1) The IC also incorporates a new technology called - Wide input range(8.0V to 26V) *absolute voltage 30V 3 TM 3 TM H Reg , a Rohm proprietary control method which - H Reg DC/DC Converter Controller included facilitates ultra-high transient response against changes in - Output Current 1.7A *1 load. SLLM (Simple Light Load Mode) technology is also - FET on resistance High-side 0.175/Low-side 0.175 integrated to improve efficiency when powering lighter - Internal soft-start function loads. For protection and ease of use, the IC also - Switching Frequency 300 to 600kHz incorporates soft start. (*According to input/output conditions) Space-saving and high efficient switching regulator can be - Fixed output voltage (5.0V 1.5% Normal Mode) achieved due to built-in N-MOSFET power transistor in Low Voltage Synchronous Buck Converter(Vout2) HTSOP-J8 package. - Input voltage range 5.0V(VOUT1) 3 TM - H Reg DC/DC Converter Controller included - Output Current 0.5A *1 Applications - FET on resistance High-side 0.25/Low-side 0.25 Distributed Power System - Internal soft-start function Pre-Regulator for Linear Regulator - Switching Frequency 1.5M to 2.5MHz (*According to input/output conditions) - Feedback voltage (0.8V 1.5% Normal Mode) Typical Application Circuit Protection Circuits Under Voltage Lockout Protection Thermal Shutdown C UP VOUT2 Over Current Protection R DW HTSOP-J8 Package with Exposed thermal PAD. R UP *1 Vout1 maximum output current capability is 2.5A, and C CO2 L2 Vout2 maximum output current capability is 1.5A with the optimal PCB power consumption design. C CO3 Structure Silicon Monolithic Integrated Circuit Package Thermal Pad HTSOP-J8 6.00mm x 4.90mm x 1.00mm (to be shorted to GND) PIN Configuration (TOP VIEW) L1 BD93291EFJ VOUT1 C VC1 C BS C CO1 Product structureSilicon monolithic integrated circuit This product is not designed protection against radioactive rays www.rohm.com 1/21 TSZ02201-0323AAJ00300-1-2 2012 ROHM Co., Ltd. All rights reserved. TSZ2211114001 12. Nov. 2012 Rev.001 VOUT 8 SW 1 BST 2 7 SWL EN 3 6 FBL GND VIN45BD93291EFJ DatasheetDatasheet Block Diagram VIN BST EN VREG VREVREVREFFF VREF 14V UVUVLUVLLOOO1 TSTSTSDDD VOUT1 VIN VOUT DRV TM H3Reg LVLVLVSSS DRV Controller LOGIC Block Vout1(5V, Fix) SW LVLVLVSSS OCP FB Current Sense 0.8V + EN Soft TSD Start UVLO1 VOUT UVLO2 VOUT2 SWL DRV DRV TM Vout2(3.3V) H3Reg Controller Block LOGIC 0.8V FBL + OCP Current EN Sense Soft UVLO2 Start TSD GND Pin Assignment and Pin Function No. Symbol Description Connect the inductor switching node of high voltage buck converter. 1 SW This pin is connected to the source node of High side FET and the drain node of Low side FET. Connect 0.1uF Boot Strap capacitor between BST pin and SW pin. 2 BST This capacitor is for generating the driving voltage of High-side N-channel MOSFET. This is Enable pin of BD93291EFJ. High input (2.3V typ.) is output active. Low input (1.8V typ.) is IC shutdown. 3 EN The internal impedance of EN pin is high, therefore add capacitor between EN and GND pin to reduce noise influence when this pin is connected to high-impedance node. Power supply pin of high voltage buck converter. 4 VIN This pin is connected to power FET supply and internal control blocks of high voltage buck converter. Connect to 10uF(recommended value) ceramic capacitor for bias capacitor. This pin is Low-side N-channel MOSFET power ground of high voltage buck converter, Low-side 5 GND N-channel MOSFET power ground of low voltage buck converter and analog ground of other blocks. This pin is output voltage feed-back pin of low voltage buck converter. Refer to ---page regarding the 6 FBL setting of output voltage. Connect the inductor switching node of low voltage buck converter. 7 SWL This pin is connected to the drain node of High side Pch-FET and the drain node of Low side FET. This pin is power supply pin of low voltage buck converter and output voltage feed-back pin of high voltage 8 VOUT buck converter. This pin is connected to power FET supply and internal control blocks of low voltage buck converter. Connect to 10uF(recommended value) ceramic capacitor for bias capacitor. www.rohm.com 2/21 TSZ02201-0323AAJ00300-1-2 2012 ROHM Co., Ltd. All rights reserved. 12. Nov. 2012 Rev.001 TSZ2211115001