RT6543A/B
Ordering Information
RT6543A/B
Marking Information
RT6543AGQW
Package Type
ML= : Product Code
QW : WQFN-20L 3x3 (W-Type)
YMDNN : Date Code
ML=YM
DNN
Lead Plating System
G : Green (Halogen Free and Pb Free)
Mode when VID changes to lower set point
A : Slew down
B : Decay down
RT6543BGQW
P7= : Product Code
YMDNN : Date Code
Note :
P7=YM
DNN
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.
Functional Pin Description
Pin No.
Pin Name
Pin Function
Current limit setting. Connect a resistor from CS pin to AGND for overcurrent
protection. CS pin sources a CS current which is 6A (typ) at TA = 25oC to
define maximum allowable output current. CS terminal voltage VCS is
limited from 0.5V to 2.8V over all operation temperature.
1
CS_DIS
Positive input pin for current sense of buck.(for load line setting, in zero load
line condition is short this pin with ISENSEN)
2
3
ISENSEP
ISENSEN
Negative input pin for current sense of buck.(for load line setting, in zero
load line condition is short this pin with ISENSEP)
Power good indicator output for VCCIN_AUX. This open-drain is pulled low
as UVP, OVP, OTP, EN low and output voltage is not regulated (such as
before soft-start). An external pull-up resistor to VCC or other external rail is
required, in which the pull-up resistor is recommended from 10k to 100k.
4
PGOOD
5
6
7
8
COMP
FB
Internal error amplifier output. For loop compensator application.
Internal error amplifier input. For loop compensator application.
Return ground for VCCIN_AUX from CPU side.
RGND
VOUT
VCCIN_AUX feedback input. This pin is unit feedback for AUX regulation
VCCIN_AUX setting pin. Use this pin to adjust AUX rail frequency setting for
different LC combination. (High state: Direct pull high to VCC, Hi-Z state:
Floating, Low state: Direct connect to GND). Default switching frequency is
floating, 600KHz. Anytime, make sure FSWSEL VCC < 0.5V.
9
FSWSEL
BOOT
Supply bootstrap capacitor output pin. The bootstrap capacitor is charged by
this pin while the low-side MOSFET is turned on. Therefore, the bootstrap
capacitor can provide the energy to turn on the high-side MOSFET. Connect
this pin through the bootstrap capacitor to the PH pin.
10
Upper gate driver with sink and source output. Connect to the gate of the
high-side MOSFET through a short and low inductance path.
11
12
UGATE
PH
Switch node of AUX. Connect to the power inductor. For the high-side gate
driver return path, connect a capacitor from PH to BOOT. Beside, this pin is
noisy, keep the sensitive trace or signal away from PH.
Copyright 2020 Richtek Technology Corporation. All rights reserved.
©
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS6543A/B-01 March 2020
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
