®
RT8237J
High Efficiency Single Synchronous Buck PWM Controller
General Description
The RT8237J 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 RT8237J 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 and enter diode emulation mode at
light load condition. The Buck conversion allows this device
to directly step down high voltage batteries at the highest
possible efficiency. The pre-set frequency selections
minimize design effort required for new designs. The
RT8237J is intended for CPU core, chipset, DRAM, or
other low voltage supplies as low as 0.7V. The RT8237J
is available in the WDFN-10L 3x3 package.
Features
Wide Input Voltage Range : 4.5V to 26V
Output Voltage Range : 0.7V to 3.3V
Built-In 0.5% 0.7V Reference Voltage
Quick Load-Step Response within 100ns
4700ppm/°C Current Source for Current Limit
RDS(ON)
Adjustable Current Limit with Low-Side MOSFET
4 Selectable Frequency Setting
Soft-Start Control
Drives Large Synchronous-Rectifier FETs
Integrated Boot Switch
Built-In OVP/OCP/UVP
Thermal Shutdown
Power Good Indicator
RoHS Compliant and Halogen Free
Applications
Notebook Computers
CPU Core Supply
Chipset/RAM Supply as Low as 0.7V
Generic DC-DC Power Regulator
Simplified Application Circuit
RT8237J
VCC
VCC
BOOT
PGOOD
EN
RF
CS
UGATE
PHASE
LGATE
GND
FB
VIN
VOUT
Copyright ©2018 Richtek Technology Corporation. All rights reserved.
DS8237J-00 August 2018
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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