RT8238B

®

DS8238B-00 July 2015

www.richtek.com

1

©

Copyright 2015 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Applications



Notebook Computers



CPU Core Supply



Chipset/RAM Supply as Low as 0.5V



Generic DC/DC Power Regulator

Single Synchronous Buck PWM Controller

Features



Built in 1% 0.5V Reference Voltage



Adjustable 0.5V to 3.3V Output Range



Quick Load Step Response within 100ns



4700ppm/

°°°°°C Programmable Current Limit by Low



4.5V to 26V Battery Input Range



Resistor Programmable Frequency



Internal Ramp Current Limit Soft-Start Control



Drives Large Synchronous Rectifier FETs



Integrated Boost Switch



Over/Under Voltage Protection



Thermal Shutdown



Power Good Indicator



RoHS Compliant and Halogen Free

Ordering Information

Note :

Richtek products are :



RoHS compliant and compatible with the current require-

ments of IPC/JEDEC J-STD-020.



Suitable for use in SnPb or Pb-free soldering processes.

Pin Configurations

(TOP VIEW)

WQFN-12L 2x2

General Description

The RT8238B PWM controller provides high efficiency,

excellent transient response, and high DC output accuracy

needed for stepping down high voltage batteries to

generate low voltage CPU core, I/O, and chipset RAM

supplies in notebook computers.

The constant on-time PWM control scheme handles wide

input/output voltage ratios with ease and provides 100ns

“instant-on” response to load transients while maintaining

a relatively constant switching frequency.

The RT8238B achieves high efficiency at a reduced cost

by eliminating the current sense resistor found in

traditional current mode PWMs. Efficiency is further

enhanced by its ability to drive very large synchronous

rectifier MOSFETs and enter diode emulation mode at

light load condition. The Audio Skipping Mode (ASM)

setting maintains the switching frequency above 25kHz,

which eliminates noise in audio applications. The buck

conversion allows this device to directly step down high

voltage batteries at the highest possible efficiency. The

RT8238B is intended for CPU core, chipset, DRAM, or

other low voltage supplies as low as 0.5V. The RT8238B

is available in a WQFN-12L 2x2 package.

LGATE

PGOOD

UGATE

PHASE

MODE

EN

6

5

4

12

10

11

1

2

3

9

8

7

GND

13

RT8238B

Package Type

QW : WQFN-12L 2x2 (W-Type)

Lead Plating System

G : Green (Halogen Free and Pb Free)

Marking Information

3Y : Product Code

W : Date Code

3YW