RT6239A Datasheet, PDF (1/22 Pages) Richtek Technology Corporation – ACOT Synchronous Step-Down Converter

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RT6239A/B
9A, 18V, 500kHz, ACOT^TM Synchronous Step-Down Converter
General Description
The RT6239A/B is a high-performance 500kHz, 9A step-
down regulator with internal power switches and
synchronous rectifiers. It features quick transient response
using its Advanced Constant On-Time (ACOT^TM) 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 proprietary ACOT^TM 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 RT6239A/B is stable with and optimized
for ceramic output capacitors. With internal 30mΩ switches
and 12mΩ synchronous rectifiers, the RT6239A/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
lockout, externally-adjustable soft-start, output under- and
over-voltage protection, and thermal shutdown provide safe
and smooth operation in all operating conditions. The
RT6239A/B is available in the UQFN-14L 2x3 (FC)
package, with exposed thermal pad.
Features
 Fast Transient Response
 Advanced Constant On-Time (ACOT^TM) Control
 4.5V to 18V Input Voltage Range
 Adjustable Output Voltage from 0.7V to 8V
 9A Output Current
 30mΩ Internal High-Side N-MOSFET and 12mΩ
Internal Low-Side N-MOSFET
 Steady 500kHz 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
 Thermal Shutdown
Applications
 Industrial and Commercial Low Power Systems
 Computer Peripherals
 LCD Monitors and TVs
 Green Electronics/Appliances
 Point of Load Regulation for High-Performance DSPs,
FPGAs, and ASICs
Simplified Application Circuit
V_IN
EN Signal
Power Good
RT6239A/B
VIN
SW
BOOT
EN
FB
PGOOD
PVCC
SS
GND
V_OUT
Copyright ©2016 Richtek Technology Corporation. All rights reserved.
DS6239A/B-04 May 2016
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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