RT6545A Datasheet, PDF (1/21 Pages) Richtek Technology Corporation – Dual-Channel Synchronous DC/DC Step-Down Controller with 5V/3.3V LDOs

®
RT6545A/B
Dual-Channel Synchronous DC/DC Step-Down Controller
with 5V/3.3V LDOs
General Description
The RT6545A/B is a dual-channel step-down, controller
generating supply voltages for battery-powered systems.
It includes two Pulse-Width Modulation (PWM) controllers
adjustable from 2V to 5.5V, and two fixed 5V/3.3V linear
regulators. Each linear regulator provides up to 100mA
output current and 3.3V linear regulator provides 1%
accuracy under 35mA. The RT6545A/B has an oscillator
output to driver the external charge pump application. Other
features include on-board power-up sequencing, a power-
good output, internal soft-start, and soft-discharge output
that prevents negative voltage during shutdown.
A constant current ripple PWM control scheme operates
without sense resistors and provides 100ns response to
load transient. For maximizing power efficiency, the
RT6545A/B automatically switches to the diode-emulation
mode in light load applications. The RT6545A/B is available
in the WQFN-20L 3x3 package.
Features
 Support Connected Standby Mode for Ultrabook
 CCRCOT Control with 100ns Load Step Response
 PWM Maximum Duty Ratio > 98%
 5V to 25V Input Voltage Range
 Dual Adjustable Output :
 CH1 : 2V to 5.5V
 CH2 : 2V to 4V
 5V/3.3V LDOs with 100mA Output Current
 1% Accuracy on 3.3V LDO Output
 Oscillator Driving Output for Charge Pump
Application
 Internal Frequency Setting
 400kHz/475kHz (CH1/CH2)
 Internal Soft-Start and Soft-Discharge
 4700ppm/°C R_DS(ON) Current Sensing
 Independent Switcher Enable Control
 Built in OVP/UVP/OCP/OTP
 Non-latch UVLO
 Power Good Indicator
 RoHS Compliant and Halogen Free
Simplified Application Circuit
V_IN
V_OUT1
VIN
UGATE2
RT6545A/B
BOOT2
UGATE1
BOOT1
PHASE2
LGATE2
PHASE1
LGATE1
FB2
CS1
BYP1
CS2
FB1
Channel 1 Enable
EN1
Channel 2 Enable
EN2
On
Off
LDO5
PGOOD
LDO3
GND
V_OUT2
5V
PGOOD Indicator
3.3V
Copyright ©2016 Richtek Technology Corporation. All rights reserved.
DS6545A/B-00 May 2016
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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