Step-Down Controller. RT8249D Datasheet

RT8249D Controller. Datasheet pdf. Equivalent

RT8249D Datasheet
Recommendation RT8249D Datasheet
Part RT8249D
Description Dual-Channel Synchronous DC/DC Step-Down Controller
Feature RT8249D; ® RT8249D Dual-Channel Synchronous DC/DC Step-Down Controller with 5V/3.3V LDOs General Descriptio.
Manufacture Richtek
Datasheet
Download RT8249D Datasheet




Richtek RT8249D
®
RT8249D
Dual-Channel Synchronous DC/DC Step-Down Controller
with 5V/3.3V LDOs
General Description
The RT8249D 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 RT8249D provides a mode
selection pin, SKIPSEL, to select Diode-Emulation Mode
(DEM) or Audio Skipping Mode (ASM). 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
RT8249D automatically switches to the diode-emulation
mode in light load applications. The RT8249D 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
500kHz/600kHz (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
20-Lead WQFN Package
RoHS Compliant and Halogen Free
Simplified Application Circuit
VIN
VOUT1
VIN UGATE2
RT8249D
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 ©2016 Richtek Technology Corporation. All rights reserved.
DS8249D-00 May 2016
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



Richtek RT8249D
RT8249D
Applications
Notebook and Sub-Notebook Computers
System Power Supplies
3-Cell and 4-Cell Li+ Battery-Powered Devices
Pin Configurations
(TOP VIEW)
Ordering Information
RT8249D
Pin 1 Orientation***
(2) : Quadrant 2, Follow EIA-481-D
Package Type
QW : WQFN-20L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
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
Marking Information
RT8249DGQW
9N=YM
DNN
9N= : Product Code
YMDNN : Date Code
Functional Pin Description
Pin No.
1
2
3
4
5
6
Pin Name
CS1
FB1
LDO3
FB2
CS2
EN2
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.
3.3V 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 4V.
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)
Switch Node of Channel 2 MOSFETs. PHASE2 is the internal lower supply rail for
8
PHASE2
the UGATE2 high-side gate driver. PHASE2 is also the current-sense input for the
Channel 2.
9
BOOT2
Bootstrap Supply for Channel 2 High-Side Gate Driver. Connect to an external
capacitor according to the typical application circuits.
10
UGATE2
High-Side Gate Driver Output for Channel 2. UGATE2 swings between PHASE2
and BOOT2.
Copyright ©2016 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8249D-00 May 2016



Richtek RT8249D
RT8249D
Pin No.
11
12
13
14
15
16
17
Pin Name
LGATE2
VIN
LDO5
BYP1
LGATE1
UGATE1
BOOT1
18 PHASE1
19 SKIPSEL
20 EN1
21
(Exposed Pad)
GND
Pin Function
Low-Side Gate Driver Output for Channel 2. LGATE2 swings between GND and
LDO5.
Power Input for 5V and 3.3V LDO Regulators and Buck Controllers.
5V Linear Regulator Output. LDO5 is also the supply voltage for the low-side
MOSFET and analog supply voltage for the device.
Switch-over Source Voltage Input for LDO5.
Low-Side Gate Driver Output for Channel 1. LGATE1 swings between GND and
LDO5.
High-Side Gate Driver Output for Channel 1. UGATE1 swings between PHASE1
and BOOT1.
Bootstrap Supply for Channel 1 High-Side Gate Driver. Connect to an external
capacitor according to the typical application circuits.
Switch Node of Channel 1 MOSFETs. PHASE1 is the internal lower supply rail for
the UGATE1 high-side gate driver. PHASE1 is also the current sense input for the
Channel 1.
PWM Operating Mode Selection.
Diode-emulation Mode : Connect to LDO3
Audio Skipping Mode : Short to GND
Enable Control Input for Channel 1.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Functional Block Diagram
BOOT1
UGATE1
PHASE1
LGATE1
FB1
CS1
LDO5
Channel 1
Buck
Controller
SKIPSEL
BYP1
SW5 Threshold
LDO5
VIN
LDO5
Channel 2
Buck
Controller
LDO5
Power-On
Sequence
Clear Fault Latch
REF
LDO3
BYP1
BOOT2
UGATE2
PHASE2
LGATE2
FB2
CS2
PGOOD
GND
EN1
EN2
LDO3
Copyright ©2016 Richtek Technology Corporation. All rights reserved.
DS8249D-00 May 2016
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3







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