Overview
The flexible step-down switching regulator controller is a switching regulator controller designed with a high-withstand-voltage built-in POWER MOS FET, providing a free setting function of operating frequency with external resistor. This switching regulator controller features a wide input voltage range (7 V to 35 V or 7 V to 48 V) and operating temperature range (-40˚C to +125˚C or
-40˚C to +95˚C). Furthermore, an external synchronization input pin (BD9781HFP) enables synchronous operation with external clock.

Features
1) Minimal external components
2) Wide input voltage range: 7 V to 35 V (BD9778F/HFP and BD9781HFP), 7 V to 48 V (BD9001F)
3) Built-in P-ch POWER MOS FET
4) Output voltage setting enabled with external resistor: 1 to VIN
5) Reference voltage accuracy: ±2%
6) Wide operating temperature range: -40˚C to +125˚C (BD9778F/HFP and BD9781HFP),
                                                  -40˚C to +95˚C (BD9001F)
8) Low dropout: 100% ON Duty cycle
9) Standby mode supply current: 0 µA (Typ.) (BD9778F/HFP and BD9781HFP), 4 µA (Typ.) (BD9001F)
10) Oscillation frequency variable with external resistor: 50 to 300 kHz (BD9001F), 50 to 500 kHz (BD9778F/HFP and BD9781HFP)
11)External synchronization enabled (only on the BD9781HFP)
12)Soft start function : soft start time fixed to 5 ms (Typ.))
13)Built-in overcurrent protection circuit
14)Built-in thermal shutdown protection circuit
15)High power HRP7 package mounted (BD9778HFP and BD9781HFP)
         Compact SOP8 package mounted (BD9778F and BD9001F)