Low Voltage Synchronous Buck Controller

The UCC3585 synchronous buck controller provides flexible high efficiency power conversion for output voltages as low as 0.9 V with ensured ±1% dc accuracy. With an input voltage range of 3.0 V to 5.5 V, it is the ideal choice for 3.3 V only, 5.0 V only, or other low voltage systems. The fixed frequency oscillator is capable of providing practical PWM operation to 500 kHz.

The UCC3585 drives a complementary pair of power MOSFET transistors. A P-channel on the high side, and an N-channel on the low side step down the input voltage at up to 90% efficiency.

A programmable two-level current limiting function is provided by sensing the voltage drop across the high side P-channel MOSFET. This circuit can be configured to provide pulse-by-pulse limiting, timed shutdown after seven consecutive faults, or latch-off after fault detection, allowing maximum application flexibility. The current limit threshold can be programmed over a wide range with a single resistor.

The UCC3585 also includes undervoltage lockout, a logic controlled enable, and softstart functions. The UCC3585 is offered in the 16-pin surface mount and through-hole packages.