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Richtek

The RT8843A/RT8843B/RT8843D is a 3/2/1 multi-phase synchronous buck controller optimized for high-performance graphic microprocessors and supports the nVidia OVR3i+ specification with a PWM-VID interface. It can support both DrMOS with current output and DCR current sensing. The RT8843A/RT8843B/RT8843D adopts AC G-NAVPTM (Green Native AVP), which is Richtek's proprietary topology derived from the finite DC gain of the internal GM amplifier with current mode control. By utilizing the AC G-NAVPTM topology, the operating frequency of the RT8843A/RT8843B/RT8843D varies with VID, load, and input voltage to further enhance efficiency, even in CCM (Continuous Conduction Mode). Moreover, the AC G-NAVPTM with CCRCOT (Constant Current Ripple COT) technology provides superior output voltage ripple over the entire input/output range.The RT8843A/RT8843B/RT8843D features an external reference input and PWM-VID dynamic output voltage control, where the output voltage is regulated and tracks the external input reference voltage. The RT8843A/RT8843B/RT8843D can set the internal RAMP amplitude through the PINSETx pin, optimizing stability and load transient performance. The RT8843A/RT8843B/RT8843D also provides complete fault protection functions, including Overvoltage Protection (OVP), Undervoltage Protection (UVP), Per-phase Current Limit, and Over-Temperature Protection (OTP). The recommended junction temperature range is from -40°C to 125°C.

應用

  • GPU Core Power for OVR3i+ Specification
主要規格
RT8843A RT8843B RT8843D
Status Active Active Active
Vin (min) (V) 2.7 2.7 2.7
Vin (max) (V) 25 25 25
Vout (min) (V) 0.3 0.3 0.3
Vout (max) (V) 2 2 2
Number of Phases 3 3 3
Accuracy (Vout>=1V) (+/- %) 1 1 1
Freq Adj Yes Yes Yes
Freq (typ) (kHz) 300 300 300
Vcc (typ) (V) 5 5 5
Features Adjustable Current Limit;Adjustable Frequency;Adjustable Soft-Start;Enable Input;OCP;OVP;Power Good;UVP Adjustable Current Limit;Adjustable Frequency;Adjustable Soft-Start;Enable Input;OCP;OVP;Power Good;UVP Adjustable Current Limit;Adjustable Frequency;Adjustable Soft-Start;Enable Input;OCP;OVP;Power Good;UVP
Package Type WQFN3x3-20 WQFN3x3-20 WQFN3x3-20
Outline Dimension, Footprint, Drawing Download Download Download
關鍵特性
  • Multi-Phase PWM Controller
  • PWM Tri-State Voltage, Pre-Short UVP
    - RT8843A: 1.95V, without Pre-Short UVP
    - RT8843B: 1.65V, without Pre-Short UVP
    - RT8843D: 1.65V, with Pre-Short UVP
  • PWM-VID Dynamic Output Voltage Control
  • Support 1.8V PWM-VID Interface
  • Power State Indicator
    - 1-Phase-DEM, Full-Phase DEM, Full-Phase CCM
  • External Reference Input Control
  • 3/2/1-Phase Hardware Setting
  • Adjustable Soft-Start Time
  • Adjustable Per-Phase Current-Limit Threshold
  • Adjustable Switching Frequency
  • UVP, OVP, OTP Protection
  • Pre-Short UVP Protection for RT8843D
  • Power-Good Indicator
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