General Description
The RT8848A/B is a 8/7/6/5/4/3/2/1 multi-phase
synchronous Buck controller which is optimized for high
performance graphic microprocessor and support
nVidia OVR4i+ spec with PWM-VID interface. The
RT8848A/B adopts AC G-NAVPTM (Green Native AVP)
which is Richtek's proprietary topology derived from
finite DC gain of internal GM amplifier with current
mode control. By utilizing the AC G-NAVPTM topology,
the operating frequency of the RT8848A/B varies with
VID, load and input voltage to further enhance the
efficiency even in CCM. Besides, for current sensing
application, the RT8848A/B can support either a
traditional DCR network current sense from inductor or
smart power stage (SPS) which can directly provide a
current monitor signal (IMON).
The RT8848A/B features external reference input and
PWM-VID dynamic output voltage control, in which the
output voltage is regulated and tracks external input
reference voltage. The RT8848A/B can set internal
RAMP amplitude through PINSETx pin and this can
optimize stability and load transient performance. The
RT8848A/B also provides complete fault protection
functions including over-voltage protection (OVP),
under-voltage protection (UVP), channel over-current
limit (CH_OC), sum output current protection (SOC)
and over-temperature protection (OTP).

Features
 Multi-Phase PWM Controller
 PWM-VID Dynamic Voltage Control
 Support 1.8V PWM-VID Interface
 Power State Indicator
 LPC (Low Phase Count), PSI = Low
 APS (Auto Phase Shedding), PSI = Mid
 HPC (High Phase Count), PSI = High
 External Reference Input Control
 8/7/6/5/4/3/2/1 Phase Hardware Setting
 Adjustable Soft-Start Time
 Adjustable Switching Frequency
 Adjustable Phase Current Balance
 Support Standby Mode
 UVP/OVP/OTP/SOC/CH_OC/TSEN Protection
 Adjustable Protection Thresholds
 Power Good Indicator
 ADC Reporting for IMON, TSEN and VSEN
 Support I2C Interface for Programming
 RoHS Compliant and Halogen Free

Applications
 GPU Core Power for OVR4i+ Spec