■ DESCRIPTION

The MB3785A is a PWM-based 4-channel switching regulator controller featuring high-precision, high-frequency capabilities. All of the four channels of circuits allow their outputs to be set in three modes: step-down, step-up, and inverted. The third and fourth channels are suited for DC motor speed control.

The triangular-wave oscillation circuit accepts a ceramic resonator, in addition to the standard method of oscillation using an RC network.

■ FEATURES

? Wide range of operating power supply voltages: 4.5 V to 18 V

? Low current consumption: 6 mA [Typ] when operating10 μA or less during standby

? Built-in high-precision reference voltage generator: 2.50 V±1

? Oscillation circuit

- Capable of high-frequency oscillation: 100 kHz to 1 MHz

- Also accepts a ceramic resonator.

? Wide input range of error amplifier: –0.2 V to VCC–1.8 V

? Built-in timer/latch-actuated short-circuiting detection circuit

? Output circuit

- The drive output for PNP transistors is the totem-pole type allowing the on-current and off-current values to be set independently.

? Adjustable dead time over the entire duty ratio range

? Built-in standby and output control functions

? High-density mounting possible: 48-pin LQFP package