RT6255A Datasheet, PDF (1/20 Pages) Richtek Technology Corporation – ACOT Step-Down Converter

®
RT6255A/B
5A, 18V, 500kHz, ACOT^TM Step-Down Converter
General Description
Features
The RT6255A/B is a high-efficiency, synchronous step- ^{ Input Supply Voltage Range : 4.5V to 18V}
down DC-DC converter that can deliver up to 5A output
current from a 4.5V to 18V input supply. The RT6255A/B
adopts Advanced Constant On-Time (ACOT^TM) control
 Output Current : 5A
 Advanced Constant On-Time (ACOT^TM) Control for
Ultrafast Transient Response
architecture to provide an ultrafast transient response with ^{ Steady Switching Frequency : 500kHz}
few external components and to operate in nearly constant
 Forced PWM Mode (RT6255B)
switching frequency over line, load, and output voltage
 Pulse-Skipping Mode (PSM) at Light Load
ranges.
(RT6255A)
The RT6255A/B features cycle-by-cycle current limit
protection against short-circuit outputs, and soft-start
function to prevent inrush current during start-up. It also
includes input under-voltage lockout, output under-voltage
protection, and over-temperature protection (thermal
shutdown) to provide safe and smooth operation in all
operating conditions.
 Optimized for Low-ESR Ceramic Output Capacitors
 Programmable Output Voltage : 0.6V to 5V
 Internal 45mΩ Switch and 23mΩ Synchronous
Rectifier
 Cycle-by-cycle Current Limit Protection
 Internal Soft-Start (Typ 1.5ms) or Externally
Adjustable, Pre-biased Compatible Soft-Start (Only
for Option with SS Pin)
Ordering Information
RT6255A/B ( )
 Power Good Indicator (90%) (Only for Option with
PGOOD Pin)
 Output Under-Voltage Protection (UVP)
Package Type
 Over-Temperature Protection (OTP)
J6F : TSOT-23-6 (FC)
J8F : TSOT-23-8 (FC)
 Input Under-Voltage Lockout (UVLO)
 Available in TSOT-23-6 (FC) and TSOT-23-8 (FC)
Lead Plating System
Packages
G : Green (Halogen Free and Pb Free)
Pin8 Definition
Empty means PGOOD pin
S : SS pin
UVP Option
H : Hiccup
PSM/PWM
A : PSM/PWM
B : Force-PWM
Applications
 Set Top Box
 Portable TV
 Access Point Router
 DSL Modem
 LCD TV
Note :
Richtek products are :
 RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
 Suitable for use in SnPb or Pb-free soldering processes.
Copyright ©2017 Richtek Technology Corporation. All rights reserved.
DS6255A/B-02 March 2017
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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