RT8204L
1
DS8204L-04 April 2011 www.richtek.com
Single Synchronous Buck Controller
General Description
The RT8204L PWM controller provides 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 RT8204L 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 RT8204L is intended for CPU core,
chipset, DRAM, or other low voltage supplies as low as
0.75V. The RT8204L is available in a WQFN-16L 3x3
package.
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 RT8204L can provide adjustable
voltage down to 0.75V and maximum output voltage is
dependen on the selected MOSFET. The internal 0.75V
reference voltage with ±1.5% accuracy provides tight
regulation of the output voltage. Other features such as
independent enable control, open drain power good
indicator, under voltage protection, and soft start make
the RT8204L a system friendly power management solution
for various applications.
Features
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PWM Controller
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` Ultra High Efficiency
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` Resistor Programmable Current Limit by Low Side
R
DS(ON)
Sense (Lossless Limit)
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` 4700ppm/
°°
°°
°C R
DS(ON)
Current Sensing
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` Quick Load Step Response within 100ns
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` 1% V
FB
Accuracy Over Line and Load
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` Adjustable 0.75V to 3.3V Output Range
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` 4.5V to 26V Battery Input Range
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` Resistor Programmable Frequency
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` Integrated Bootstrap Switch
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` Over/Under Voltage Protection
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` Voltage Ramp Soft-Start
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` Power Good Indicator
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z LDO Controller
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` 1.5% accuracy Over Line and Load
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` Independent Enable and Power Good Indicator
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` Drive N-MOSFETs within Rail to Rail Controller
Voltage
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` MLCC and POSCAP Stable
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z RoHS Compliant and Halogen Free
Applications
z Notebook Computers
z CPU Core Supply
z Chipset/RAM Supply as Low as 0.75V
Ordering Information
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.
RT8204L
Package Type
QW : WQFN-16L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Z : ECO (Ecological Element with
Halogen Free and Pb free)
