W83321S/W83321G

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1. GENERAL DESCRIPTION

The W83321S is a high-speed, N-Channel synchronous buck regulator controller. The W83321S

employs fixed-frequency voltage-mode PWM control architecture. Both high-side and low-side

MOSFETs are lower cost N-Channel type. The regulator is biased from a 5V rail and the power for the

high-side MOSFET can be supplied by a separate 12V rail or supplied from a local charge pump.

Current limit is achieved by monitoring the voltage drop across the on resistance of the low-side

MOSFET. This method eliminates the requirement of extra current sensing resistor and avoids false

avoid potential shoot-through problems while maintaining high efficiency.

2. FEATURES

Operates from +5V Input

0.8V to VIN Output Range

- 0.8V Internal Reference

- ±1.5% Over Line Voltage and Temperature

Drives N-Channel MOSFETs

Simple Single-Loop Control Design

- Voltage-Mode PWM Control

Fast Transient Response

Lossless, Programmable Overcurrent Protection

- Uses Lower MOSFET’s Rds (on)

- Current limit without sense resistor

Small Converter Size

- 250 kHz Fixed Frequency Oscillator

- Internal Soft Start

- Tiny plastic SOP-8 package