®
RT6343
42V
IN
, 3.5A, Asynchronous Step-Down Converter with Low
Quiescent Current
General Description
The RT6343 is a 3.5A, high-efficiency, peak current mode
control asynchronous step-down converter. The device
operates with input voltages from 4V to 42V. The device
can program the output voltage between 0.8V to VIN. The
low quiescent current design with the integrated low R
DS(ON)
of high-side MOSFET achieves high efficiency over the
wide load range. The peak current mode control with simple
external compensation allows the use of small inductors
and results in fast transient response and good loop
stability.
The wide switching frequency of 100kHz to 2500kHz allows
for efficiency and size optimization when selecting the
output filter components. The ultra-low minimum on-time
enables constant-frequency operation even at very high
step-down ratios. For switching noise sensitive
applications, it can be externally synchronized from
300kHz to 2200kHz.
The RT6343 provides complete protection functions such
as input under-voltage lockout, output under-voltage
protection, output over-voltage protection, over-current
protection, and thermal shutdown. Cycle-by-cycle current
limit provides protection against shorted outputs, and soft-
start eliminates input current surge during start-up. The
RT6343 is available in WDFN-10L 4x4 and SOP-8
(Exposed pad) packages.
Features
Wide Input Voltage Range
4.5V to 42V
�½
4V to 42V (Soft-start is finished)
�½
Wide Output Voltage Range : 0.8V to VIN
0.8V
±
1% Reference Accuracy
Peak Current Mode Control
Integrated 80mΩ High-Side MOSFET
Ω
Low Quiescent Current : 100μA
μ
Low Shutdown Current : 2.25μA
μ
Adjustable Switching : 100kHz to 2.5MHz
Synchronizable Switching : 300kHz to 2.2MHz
Power Saving Mode (PSM) at Light Load
Low Dropout at Light Loads with Integrated Boot
Recharge FET
Externally Adjustable Soft-Start by Part Number
Option
Power Good Indication by Part Number Option
Enable Control
Adjustable UVLO Voltage and Hysteresis
Built-In UVLO, UVP, OVP, OCP, OTP
Applications
12V and 24V Power Systems
GPS, Entertainment
Simplified Application Circuit
RT6343GQW
V
IN
C
IN
Enable Signal
PGOOD
R
RT
RT/SYNC
C
COMP1
R
COMP
COMP
C
COMP2
GND PAD
SS/TR
EN
PGOOD
FB
R
FB2
VIN
BOOT
SW
D1
R
FB1
C
OUT
C
BOOT
L1
V
OUT
RT6343GSP
V
IN
C
IN
VIN
BOOT
SW
C
BOOT
L1
V
OUT
D1
R
FB1
C
OUT
Enable Signal
C
COMP1
R
COMP
EN
FB
R
FB2
COMP
C
SS
C
COMP2
RT/SYNC
GND PAD
R
RT
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6343-00
October 2019
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
