General Description
The RT8820A is a 2/1 phase synchronous Buck PWM
controller which is optimized for high performance graphic
microprocessor and computer applications. The IC
integrates a Constant-On-Time (COT) PWM controller, two
MOSFET drivers with internal bootstrap diodes, as well
as channel current balance and protection functions
including Over-Voltage Protection (OVP), Under-Voltage
Protection (UVP), current limit, and thermal shutdown into
the WQFN-20L 3x3 package.
The RT8820A adopts RDS(ON) current sensing technique.
Current limit is accomplished through continuous inductorcurrent-
sense, while RDS(ON) current sensing is used for
accurate channel current balance. Using the method of
current sampling utilizes the best advantages of each
technique.
The RT8820A features external reference input and PWMVID
dynamic output voltage control, in which the feedback
voltage is regulated and tracks external input reference
voltage. Other features include adjustable switching
frequency, dynamic phase number control, internal softstart,
power good indicator, and enable functions.

Features
 Dual-Phase PWM Controller
 Power State Indicator
 1P-CCM/2P-CCM/1P-DEM/2P-DEM
 Two Embedded MOSFET Drivers and Embedded
Switching Boot Diode
 Support 1.8V PWM-VID Interface
 External Reference Input Control
 PWM-VID Dynamic Voltage Control
 Dynamic Phase Number Control
 Lossless RDS(ON) Current Sensing for Current Balance
 Internal/External Soft-Start
 Adjustable Current Limit Threshold
 Adjustable Switching Frequency
 UVP/OVP Protection
 Shoot Through Protection and Short Pulse Free
Technology
 Support an Ultra-Low Output Voltage as Standby
Voltage
 Thermal Shutdown
 Power Good Indicator (EN to PG high = 500μs)

Applications
 CPU/GPU Core Power Supply
 Desktop PC Memory, VTT Power
 Chipset/RAM Power Supply
 Generic DC-DC Power Regulator