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