Description

The L4973 is a step down monolithic power switching regulator delivering 3.5A at fixed voltages of 3.3V or 5.1V and using a simple external divider output adjustable voltage up to 50V. Realized in BCD mixed technology, the device uses an internal power D-MOS transistor (with a typical RDS(on) of 0.15Ω) to obtain very high efficiency and very fast switching times. Switching frequency up to 300KHz are achievable (the maximum power dissipation of the packages must be observed).

Features

■ Up to 3.5A step down converter

■ Operating input voltage from 8V to 55V

■ 3.3V and 5.1V (±1) fixed output, and adjustable outputs from:

– 0.5V to 50V (3.3 type)

– 5.1V to 50V (5.1 type)

■ Frequency adjustable up to 300kHz

■ Voltage feed forward

■ Zero load current operation (min 1mA)

■ Internal current limiting (pulse by pulse and HICCUP mode)

■ Precise 5.1V (1.5) reference voltage externally available

■ Input/output synchronization function

■ Inhibit for zero current consumption (100mA typ. at VCC = 24V)

■ Protection against feedback disconnection

■ Thermal shutdown

■ Output over voltage protection

■ Soft start function