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RT7257B
3A, 18V, 1.2MHz Synchronous Step-Down Converter
General Description
Features
1.5% High Accuracy Reference Voltage
The RT7257B is a high efficiency, monolithic synchronous
step-down DC/DC converter that can deliver up to 3A
output current from a 4.5V to 18V input supply. The
RT7257B's current mode architecture and external
compensation allow the transient response to be
optimized over a wide input voltage range and loads.
Cycle-by-cycle current limit provides protection against
shorted outputs, and soft-start eliminates input current
surge during start-up. The RT7257B also provides under
voltage protection and thermal shutdown protection. The
low current (<3μA) shutdown mode provides output
disconnection, enabling easy power management in
battery-powered systems. The RT7257B is available in
an SOP-8 (Exposed Pad) package.
4.5V to 18V Input Voltage Range
3A Output Current
Integrated N-MOSFET Switches
Current Mode Control
Fixed Frequency Operation : 1.2MHz
Output Adjustable from 0.8V to 12V
Up to 95% Efficiency
Programmable Soft-Start
Stable with Low ESR Ceramic Output Capacitors
Cycle-by-Cycle Over Current Protection
Input Under Voltage Lockout
Output Under Voltage Protection
Thermal Shutdown Protection
RoHS Compliant and Halogen Free
Ordering Information
RT7257B
Applications
Wireless AP/Router
Package Type
SP : SOP-8 (Exposed Pad-Option 1)
Set-Top-Box
Industrial and Commercial Low Power Systems
LCDMonitors and TVs
Lead Plating System
Z : ECO (Ecological Element with
Halogen Free and Pb free)
Green Electronics/Appliances
Point of Load Regulation of High-PerformanceDSPs
H : UVP Hiccup
L : UVP Latch-Off
Note :
Pin Configurations
Richtek products are :
(TOP VIEW)
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
8
BOOT
VIN
SS
Suitable for use in SnPb or Pb-free soldering processes.
2
3
4
7
6
5
EN
GND
SW
COMP
FB
9
GND
Marking Information
RT7257BxZSP : Product Number
SOP-8 (Exposed Pad)
RT7257Bx
ZSPYMDNN
x : H or L
YMDNN : Date Code
Copyright 2016 Richtek Technology Corporation. All rights reserved.
©
is a registered trademark of Richtek Technology Corporation.
DS7257B-04 October 2016
www.richtek.com
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