RT8238B Datasheet, PDF (1/15 Pages) Richtek Technology Corporation – Single Synchronous Buck PWM Controller

®
RT8238B
Single Synchronous Buck PWM Controller
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.
Ordering Information
RT8238B
Package Type
QW : WQFN-12L 2x2 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
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.
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
Side R_DS(ON) Sensing
 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
Applications
 Notebook Computers
 CPU Core Supply
 Chipset/RAM Supply as Low as 0.5V
 Generic DC/DC Power Regulator
Pin Configurations
(TOP VIEW)
12 11 10
LGATE ¹
PHASE 2
UGATE 3
GND
13
9 PGOOD
8 EN
7 _MODE
4 56
WQFN-12L 2x2
Marking Information
3Y : Product Code
3YW
W : Date Code
Copyright ©2015 Richtek Technology Corporation. All rights reserved.
DS8238B-00 July 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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