RT6543A/B
Ordering Information
RT6543A/B
Package Type
QW : WQFN-20L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Mode when VID changes to lower set point
A : Slew down
B : Decay down
Note :
Richtek products are :
�½
Marking Information
RT6543AGQW
ML= : Product Code
ML=YM
DNN
YMDNN : Date Code
RT6543BGQW
P7= : Product Code
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.
P7=YM
DNN
YMDNN : Date Code
�½
Functional Pin Description
Pin No.
1
Pin Name
CS_DIS
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 T
A
= 25
o
C to
define maximum allowable output current. CS terminal voltage VCS is
limited from 0.5V to 2.8V over all operation temperature.
Positive input pin for current sense of buck.(for load line setting, in zero load
line condition is short this pin with 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.
Internal error amplifier output. For loop compensator application.
Internal error amplifier input. For loop compensator application.
Return ground for VCCIN_AUX from CPU side.
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.
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.
Upper gate driver with sink and source output. Connect to the gate of the
high-side MOSFET through a short and low inductance path.
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.
is a registered trademark of Richtek Technology Corporation.
2
3
ISENSEP
ISENSEN
4
5
6
7
8
9
PGOOD
COMP
FB
RGND
VOUT
FSWSEL
10
BOOT
11
12
UGATE
PH
Copyright
©
2020 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
DS6543A/B-01 March 2020
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
