RT7277 Datasheet, PDF (1/14 Pages) Richtek Technology Corporation – 3A, 18V, 700kHz ACOTTM Synchronous Step-Down Converter

®
RT7277
3A, 18V, 700kHz ACOT^TM Synchronous Step-Down Converter
General Description
The RT7277 is a synchronous step-down DC/DC converter
with Advanced Constant On-Time (ACOT^TM) mode control.
It achieves high power density to deliver up to 3A output
current from a 4.5V to 18V input supply. The proprietary
ACOT^TM mode offers an optimal transient response over a
wide range of loads and all kinds of ceramic capacitors,
which allows the device to adopt very low ESR output
capacitors for ensuring performance stabilization. In
addition, RT7277 keeps an excellent constant switching
frequency under line and load variation and the integrated
synchronous power switches with the ACOT^TM mode
operation provides high efficiency in whole output current
load range. Cycle-by-cycle current limit provides an
accurate protection by a valley detection of low side
MOSFET and external soft-start setting eliminates input
current surge during startup. Protection functions also
include output under voltage protection, output over voltage
protection, and thermal shutdown.
Marking Information
RT7277
GSPYMDNN
RT7277GSP : Product Number
YMDNN : Date Code
Features
z ACOT^TM Mode Enables Fast Transient Response
z 4.5V to 18V Input Voltage Range
z 3A Output Current
z 60mΩ Internal Low Site N-MOSFET
z Advanced Constant On-Time Control
z Support All Ceramic Capacitors
z Up to 95% Efficiency
z 700kHz Switching Frequency
z Adjustable Output Voltage from 0.765V to 8V
z Adjustable Soft-Start
z Cycle-by-Cycle Current Limit
z Input Under Voltage Lockout
z Thermal Shutdown
z RoHS Compliant and Halogen Free
Applications
z Industrial and Commercial Low Power Systems
z Computer Peripherals
z LCD Monitors and TVs
z Green Electronics/Appliances
z Point of Load Regulation for High-Performance DSPs,
FPGAs, and ASICs
Simplified Application Circuit
V_IN
C1
Chip Enable
RT7277
VIN
SW
C2
BOOT
EN
FB
SS
PVCC
C5
GND
L1
V_OUT
C6
C7
C3 R1
V_PVCC ^R2
C4
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS7277-00 October 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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