[Richtek]

General Description

The RT9221 integrates a PWM controller and two low-dropout linear regulators into a single chip. The PWM controller provides the CPU core voltage controlled by a 5-bit DAC and the linear section regulates power for GTL bus, clock driver or other circuits on motherboards.

Features

• Provides 3 Regulated Voltages

• N-MOSFET Driver for High Efficiency Switching Section

• Power-good, Over-voltage, and Currentlimiting Protection for Switching Section

• 1.5V and 2.5V Fixed Output Voltage for Linear Section

• Linear Section Uses Low Cost NPN Transistor as Power Device

• TTL-compatible 5-bit DAC Core Output Voltage

Applications

• Power Supply for Pentium, Pentium ProTM, Pentium IITM, Power PCTM, K6TM, 6×86TM, and AlphaTM Microprocessors

• High-power 5V to 3.xV DC-DC Regulators

• Low-voltage Distributed Power Supplies

• Programmable Power Supplies