General Description
The RT8845B is a 4/3/2/1 phase synchronous Buck PWM
controller which is optimized for high performance graphic
microprocessor and computer applications. The RT8845B
adopts G-NAVPTM (Green Native AVP) which is Richtek's
proprietary topology derived from finite DC gain of EA
amplifier with current mode control. By utilizing the GNAVPTM
topology, the operating frequency of the RT8845B
varies with VID, load and input voltage to further enhance
the efficiency even in CCM. Moreover, the G-NAVPTM with
CCRCOT (Constant Current Ripple COT) technology
provides superior output voltage ripple over the entire input/
output range. The RT8845B provides complete fault
protection functions including Over-Voltage (OV), Negative
Voltage (NV), Over-Current (OC) and Under-Voltage
Lockout (UVLO). The RT8845B is available in the WQFN-
32L 4x4 package.
The RT8845B 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/external
soft- start, power good indicator, and enable functions.

Features
 Multi-Phase PWM Controller
 Power State Indicator
 1P-CCM/4P-CCM/1P-DEM
 Support 1.8V PWM-VID Interface
 External Reference Input Control
 PWM-VID Dynamic Voltage Control
 Dynamic Phase Number Control
 Internal/External Soft-Start
 Adjustable Current Limit Threshold
 Adjustable Switching Frequency
 UVP/OVP Protection
 Support an Ultra-Low Output Voltage as Standby
Voltage
 Thermal Shutdown
 Power Good Indicator

Applications
 GPU Core Supply for nVidia OVR4 + Spec.