®
RT7291A/B
6A, 23V, 500kHz, ACOT
TM
Synchronous Buck Converter
with LDO for System 5V
General Description
The RT7291A/B is a synchronous Buck converter with
Advanced Constant On-Time (ACOT
TM
) mode control. The
main control loop of the RT7291A/B uses an ACOT
TM
mode control which provides a very fast transient response
with no external compensators. The RT7291A/B operates
from 5V to 23V input voltage, provides a 5V LDO and a
300kHz CLK to drive an external charge pump. OCP, UVP
and OVP are included in the RT7291A/B. This IC also
provides a 1.5ms internal soft-start function and an open-
drain power good indicator.
Features
5V to 23V Input Voltage Range
Up to 98% Duty for 2S Battery Application
PWM Frequency Fixed 500kHz
ACOT
TM
Mode Performs Fast Transient Response
Integrated MOSFETs
Ω
�½
31mΩ of High-Side MOSFET
�½
20mΩ of Low-Side MOSFET
Ω
Support Output MLCC Stable
Internal Soft-Start (1.5ms typ)
Built-in OVP/UVP/OCP
Power Good Indicator
Fixed 300kHz VCLK to Support Charge Pump
Individual EN for PWM and LDO
Thermal Shutdown
Applications
Laptop Computers
Tablet PCs
Networking Systems
Servers
Personal Video Recorders
Flat Panel Television and Monitors
Distributed Power Systems
Simplified Application Circuit
D1
V
OUT
C1
C2
C3
C4
C5
D2
D3
D4
V
CP
V
IN
C
IN
V
LDO
VIN
EN
LDO
C
LDO
R
BYP
C
BYP
CLK
RT7291A/B
R
B
BOOT
C
B
L
SW
VOUT
PGND
C
OUT
V
OUT
V
OUT
VBYP
PGOOD
VCC
ENLDO AGND
R
PGOOD
V
CC
C
VCC
Copyright
©
2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS7291A/B-03 January 2018
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
