®
RT6236A/B
6A, 18V, 650kHz, ACOTTM Synchronous Step-Down Converter
General Description
Features
Fast Transient Response
The RT6236A/B is a high-performance 650kHz, 6Astep-
down regulator with internal power switches and
synchronous rectifiers. It features quick transient response
using its Advanced Constant On-Time (ACOTTM) control
architecture that provides stable operation with small
ceramic output capacitors and without complicated
external compensation, among other benefits. The input
voltage range is from 4.5V to 18V and the output is
adjustable from 0.7V to 8V. The proprietaryACOTTM control
improves upon other fast response constant on-time
architectures, achieving nearly constant switching
frequency over line, load, and output voltage ranges. Since
there is no internal clock, response to transients is nearly
instantaneous and inductor current can ramp quickly to
maintain output regulation without large bulk output
capacitance. The RT6236A/B is stable with and optimized
for ceramic output capacitors. With internal 51mΩ switches
and 18mΩ synchronous rectifiers, the RT6236A/B displays
excellent efficiency and good behavior across a range of
applications, especially for low output voltages and low
duty cycles. Cycle-by-cycle current limit provides
protection against shorted outputs, input under-voltage
lock-out, externally-adjustable soft-start, output under- and
over-voltage protection, and thermal shutdown provide safe
and smooth operation in all operating conditions. The
RT6236A/B is available in the UQFN-13JL 2x3 (FC)
package, with exposed thermal pad.
Advanced Constant On-Time (ACOTTM) Control
4.5V to 18V Input Voltage Range
Adjustable Output Voltage from 0.7V to 8V
6A Output Current
51mΩ Internal High-Side N-MOSFET and 18mΩ
Internal Low-Side N-MOSFET
Steady 650kHz Switching Frequency
Up to 95% Efficiency
Optimized for All Ceramic Capacitors
Externally-Adjustable, Pre-Biased Compatible Soft-
Start
Cycle-by-Cycle Current Limit
Input Under-Voltage Lockout
Output Over- and Under-Voltage Protection
Power Good Output
Externally-Adjustable, Pre-Biased Compatible Soft-
Start
Thermal Shutdown
Applications
Industrial and Commercial Low Power Systems
Computer Peripherals
LCDMonitors and TVs
Green Electronics/Appliances
Point of Load Regulation for High-Performance DSPs,
FPGAs, and ASICs
Simplified Application Circuit
L
RT6236A/B
VIN
V
SW
OUT
V
IN
C
C
C
BOOT
IN
C
OUT
BOOT
R1
R2
C
FF
R
PG
V
PGOOD
EN
PVCC
FB
Enable
SS
PVCC
V
PVCC
C
SS
PVCC
GND
Copyright 2016 Richtek Technology Corporation. All rights reserved.
©
is a registered trademark of Richtek Technology Corporation.
DS6236A/B-02 August 2016
www.richtek.com
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