RT8204AGQW Datasheet, PDF (1/19 Pages) Richtek Technology Corporation – Single Synchronous Buck with LDO Controller

RT8204A
Single Synchronous Buck with LDO Controller
General Description
The RT8204A PWM controller provides the high efficiency,
excellent transient response, and high DC output accuracy
needed for stepping down high voltage batteries to
generate low voltage CPU core, I/O, and chipset RAM
supplies in notebook computers.
The constant-on-time PWM control scheme handles wide
input/output voltage ratios with ease and provides 100ns
“instant-on” response to load transients while maintaining
a relatively constant switching frequency.
The RT8204A achieves high efficiency at a reduced cost
by eliminating the current sense resistor found in
traditional current mode PWMs. Efficiency is further
enhanced by its ability to drive very large synchronous
rectifier MOSFETs. The buck conversion allows this device
to directly step down high voltage batteries for the highest
possible efficiency. The RT8204A is intended for CPU core,
chipset, DRAM, or other low voltage supplies as low as
0.75V.
A built-in LDO controller can drive an external N-MOSFET
to provide a second output voltage from PWM output or
other power source. The RT8204A can provide adjustable
voltage down to 0.75V and maximum output voltage is
depended on the selected MOSFET. The internal 0.75V
reference voltage with ±1.5% accuracy provides tight
regulation for the output voltage. The independent enable
control, open drain power good indicator, under-voltage
protection and soft start make RT8204A to power the
system friendly. The RT8204A is available in WQFN-16L
3x3 package.
Applications
z Notebook Computers
z CPU Core Supply
z Chipset/RAM Supply as Low as 0.75V
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Features
z PWM Controller
` Ultra-High Efficiency
` Resistor Programmable Current Limit by Low Side
R_DS(ON) Sense (Lossless Limit) or Sense Resistor
(High Accuracy)
` Quick Load Step Response within 100ns
` 1% V_OUT Accuracy Over Line and Load
` Adjustable 0.75V to 3.3V Output Range
` 3V to 26V Battery Input Range
` Resistor Programmable Frequency
` Over/Under Voltage Protection
` 2 Steps Current Limit During Soft-Start
` Drives Large Synchronous-Rectifier FETs
` Power Good Indicator
z LDO Controller
` 1.5% Accuracy Over Line and Load
` Adjustabe Output Voltage down to 0.75V
` Independent Enable and Power Good Indicator
` Drive N-MOSFETs within Rail to Rail Controller
Voltage
` MLCC and POSCAP Stable
z RoHS Compliant and 100% Lead (Pb)-Free
Ordering Information
RT8204A
Package Type
QW : WQFN-16L 3x3 (W-Type)
Note :
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
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.
DS8204A-05 April 2011
www.richtek.com
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