RT8238A
2
RT8238A-07 January 2014
www.richtek.com
©
Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
Pin No.
Pin Name
Pin Function
1
LGATE
Gate Drive Output for Low Side External MOSFET.
2 PHASE
External Inductor Connection Pin for PWM Converter. It behaves as the current
sense comparator input for Low Side MOSFET R
DS(ON)
sensing and reference
voltage for on time generation.
3
UGATE
Gate Drive Output for High Side External MOSFET.
4 BOOT
Supply Input for High Side Driver. Connect through a capacitor to the floating
node (PHASE) pin.
5 VCC
Control Voltage Input. Provides the power for the buck controller, the low side
driver and the bootstrap circuit for high side driver. Bypass to GND with a 1
μ
F
ceramic capacitor.
6 FB
V
OUT
Feedback Input. Connect FB to a resistive voltage divider from V
OUT
to
GND to adjust the output from 0.5V to 3.3V
7 MODE
Pull down to GND for Forced CCM Mode.
Pull up to 2.5V for Audio Skipping Mode (ASM).
Pull up to 5V for Diode Emulation Mode (DEM).
8
EN
PWM Chip Enable. Pull low to GND to disable the PWM.
Functional Pin Description
Typical Application Circuit
VCC
CS
UGATE
FB
RT8238A
LGATE
BOOT
PHASE
MODE
V
IN
PGOOD
PGOOD
GND
TON
VDDP
R2
C2
R
TON
Q1
Q2
C1
1V
EN
R6
100k
1µF
0
R4
R5
C3
0
0.1µF
4.5V to 26V
C4
10µF
R7*
C7*
R8
R9
L1
C5* C6*
220µF
10k
10k
* : Optional
V
OUT
Chip Enable
To 5V : DEM
To 2.5V : ASM
To GND : Forced-CCM
11
5
9
10
8
12, 13 (Exposed Pad)
7
6
1
2
3
4
Marking Information
CP : Product Code
W : Date Code
RT8238AGQW
CP : Product Code
W : Date Code
RT8238AZQW
CPW
CPW
