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The RT6543A/B PWM controller provides high efficiency, excellent transient response, and high DC output accuracy for stepping down high voltage batteries to generate low voltage CPU core, I/O, and chipset RAM.

The RT6543A/B supports on chip voltage programming function between 0V and 1.8V by controlling VID1/VID0 inputs.

Compared with conventional current-mode PWMs, the RT6543A/B achieves high efficiency without any current sensing resistors. Furthermore, the RT6543A/B has ability to drive synchronous rectifier MOSFETs and enters diode emulation mode at light load condition that also save lots of power consumption. Besides, the RT6543A/B equips with UVLO, OVP, UVP, OTP and current limit protection. All above functions are integrated in a WQFN-20L-3x3 package.

Applications

  • Notebook Computers
  • CPU/GPU Core Supply
  • Chipset/RAM Supply
  • Generic DC-DC Power Regulator
Key Spec.
RT6543A RT6543B
Status Active Active
Vs (typ) (V) 5 5
Vin (min) (V) 3 3
Vin (max) (V) 24 24
Vout (min) (V) 1.1 1.1
Vout (max) (V) 1.8 1.8
Output Adj. Method Fixed Fixed
Accuracy (+/- %) 1 1
Freq (typ) (kHz) 600 600
Freq (min) (kHz) 400 400
Freq (max) (kHz) 800 800
Iq (typ) (mA) 0.3 0.3
Ext Sync No No
Features Adjustable Current Limit;Adjustable Frequency;Built-in Bootstrap Switch;COT Control;Cycle-by-Cycle Current Limit;DCR Current Sense;Diode Emulation Mode;Droop Control;Droop Control;Enable Input;Fast Transient Response;OCP;OVP;Power Good;UVP Adjustable Current Limit;Adjustable Frequency;Built-in Bootstrap Switch;COT Control;Cycle-by-Cycle Current Limit;DCR Current Sense;Diode Emulation Mode;Droop Control;Droop Control;Enable Input;Fast Transient Response;OCP;OVP;Power Good;UVP
Package Type WQFN3x3-20 WQFN3x3-20
Features
  • A High Efficiency Step-Down DC-DC Controller
  • Built-in 1% Reference Voltage
  • 2-Bit Programmable Output Voltage with Integrated
  • Adjustable Switching Frequency
  • Input Voltage Range : 3V to 24V
  • Internal Soft-Start to Reduce Inrush Current
  • Capability of Driving Large Synchronous Rectifier MOSFETs
  • Power Good Indicator
  • Cycle-by-Cycle Current Limit
  • Over-/Under-Voltage Protection
  • Thermal Shutdown
  • RT6543A : Slew Down Mode as VID Change
  • RT6543B : Decay Down Mode as VID Change
Technical Documents
TitleItem TypeLast UpdateDownload
Richtek Product Selection Guide [Jan., 2024] Selection Guide2024/01/18
Part NumberPackage TypePackage Qty.Free SampleDistributorStockBuy From Authorized Distributor
RT6543AGQWWQFN3x3-201,500 Request Digikey 2,632 Buy
Mouser 2,697 Buy
RT6543AGQWWQFN3x3-203,000 Request Digikey 2,632 Buy
Mouser 2,697 Buy
RT6543BGQWWQFN3x3-203,000 Request Digikey 5,937 Buy
Mouser 2,975 Buy
Please confirm with our distributor or sales representative for actual stock status.
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