W83321S Datasheet, PDF (4/18 Pages) Winbond – N-Channel FET Synchronous Buck Regulator Controller

W83321S/W83321G
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
trigger of OC protection when V_IN varies. The adaptive non-overlapping MOSFET gate drivers help
avoid potential shoot-through problems while maintaining high efficiency.
2. FEATURES
y Operates from +5V Input
y 0.8V to VIN Output Range
- 0.8V Internal Reference
- ±1.5% Over Line Voltage and Temperature
y Drives N-Channel MOSFETs
y Simple Single-Loop Control Design
- Voltage-Mode PWM Control
y Fast Transient Response
y Lossless, Programmable Overcurrent Protection
- Uses Lower MOSFET’s Rds (on)
- Current limit without sense resistor
y Small Converter Size
- 250 kHz Fixed Frequency Oscillator
- Internal Soft Start
- Tiny plastic SOP-8 package
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