RT6585B Step-Down Controller Datasheet

RT6585B Datasheet, PDF, Equivalent


Part Number

RT6585B

Description

Dual-Channel Synchronous DC/DC Step-Down Controller

Manufacture

Richtek

Total Page 20 Pages
Datasheet
Download RT6585B Datasheet


RT6585B
®
RT6585A/B
Dual-Channel Synchronous DC/DC Step-Down Controller
with 5V/3.3V LDOs
General Description
The RT6585A/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 RT6585A/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
RT6585A/B automatically switches to the diode-emulation
mode in light load applications. The RT6585A/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
2V to 5.5V Output Voltage Range
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 RDS(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
VIN
VOUT1
VIN UGATE2
RT6585A/B
BOOT2
UGATE1
BOOT1
PHASE2
LGATE2
PHASE1
LGATE1
FB2
CS1
BYP1
CS2
FB1
Channel 1 Enable
EN1
Channel 2 Enable
On
Off
EN2
LDO5
PGOOD
LDO3
GND
VOUT2
5V
PGOOD Indicator
3.3V
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS6585A/B-02 June 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1

RT6585B
RT6585A/B
Applications
Marking Information
Notebook and Sub-Notebook Computers
System Power Supplies
3-Cell and 4-Cell Li+ Battery-Powered Devices
Ordering Information
RT6585A/B
Pin 1 Orientation***
(2) : Quadrant 2, Follow EIA-481-D
Package Type
QW : WQFN-20L 3x3 (W-Type)
RT6585AGQW
3J=YM
DNN
3J= : Product Code
YMDNN : Date Code
RT6585BGQW
3H=YM
DNN
3H= : Product Code
YMDNN : Date Code
Lead Plating System
G : Green (Halogen Free and Pb Free)
Pin Function With
A : LDO3 Always On
B : LDO3/LDO5 Always On
Pin Configurations
(TOP VIEW)
Note :
***Empty means Pin1 orientation is Quadrant 1
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.
CS1
FB1
LDO3
FB2
CS2
20 19 18 17 16
1 15 LGATE1
2 14 BYP1
3 GND 13 LDO5
4 21 12 VIN
5 11 LGATE2
6 7 8 9 10
WQFN-20L 3x3
Functional Pin Description
Pin No.
1
2
Pin Name
CS1
FB1
Pin Function
Current Limit Setting. Connect a resistor to GND to set the threshold for Channel 1
synchronous RDS(ON) sense. The GND PHASE1 current limit threshold is 1/8th
the voltage seen at CS1 over a 0.2V to 2V range. There is an internal 50A
current source from LDO5 to CS1.
Feedback Voltage Input for Channel 1. Connect FB1 to a resistive voltage divider
from VOUT1 to GND to adjust output from 2V to 5.5V.
3 LDO3
4 FB2
5 CS2
6 EN2
3.3V Linear Regulator Output. It is always on when VIN is higher than VINPOR
threshold.
Feedback Voltage Input for Channel 2. Connect FB2 to a resistive voltage divider
from VOUT2 to GND to adjust output from 2V to 5.5V.
Current Limit Setting. Connect a resistor to GND to set the threshold for Channel 2
synchronous RDS(ON) sense. The GND PHASE2 current limit threshold is 1/8th
the voltage seen at CS2 over a 0.2V to 2V range. There is an internal 50A
current source from LDO5 to CS2.
Enable Control Input for Channel 2.
7
PGOOD
Power Good Indicator Output for Channel 1 and Channel 2. (Logical AND)
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS6585A/B-02 June 2014


Features ® RT6585A/B Dual-Channel Synchronous D C/DC Step-Down Controller with 5V/3.3V LDOs General Description The RT6585A/B is a dual-channel step-down, controlle r generating supply voltages for batter y-powered systems. It includes two Puls e-Width Modulation (PWM) controllers ad justable 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 provi des 1% accuracy under 35mA. The RT6585A /B has an oscillator output to driver t he external charge pump application. Ot her features include on-board power-up sequencing, a powergood output, interna l 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 t o load transient. For maximizing power efficiency, the RT6585A/B automatically switches to the diode-emulation mode i n light load applications. The RT6585A/B is available in the WQF.
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