Dual-Channel Synchronous DC-DC Step-Down Controller with 5V/3.3V LDOs


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The RT6575A/B is a dual-channel step-down controller generating supply voltages for battery-powered systems. It includes two Pulse-Width Modulation (PWM) controllers adjustable from 2V to 5.5V, and two fixed 5V/3.3V linear regulators. Each linear regulator provides up to 100mA output current and 3.3V linear regulator provides 1% accuracy under 35mA. The RT6575A/B has an oscillator output to drive the external charge pump application. Other features include on-board power-up sequencing, a power-good output, internal soft-start, and soft-discharge output that prevents negative voltage during shutdown.

A constant current ripple PWM control scheme operates without sense resistors and provides 100ns response to load transient. For maximizing power efficiency, the RT6575A/B automatically switches to the diode-emulation mode in light load applications. The RT6575A/B is available in the WQFN-20L 3x3 package.


  • Notebook and Sub-Notebook Computers
  • System Power Supplies
  • 2-Cell to 4-Cell Li+ Battery-Powered Devices
Key Spec.
RT6575A RT6575B
Status Active Active
Vs (typ) (V) 12 12
Vin (min) (V) 5 5
Vin (max) (V) 25 25
Vout (min) (V) 2 2
Vout (max) (V) 5.5 5.5
Output Adj. Method Resistor Resistor
Accuracy (+/- %) 1 1
Iout (max) (A) 20 20
Freq (typ) (kHz) 300 300
Freq (min) (kHz) 240 240
Freq (max) (kHz) 360 360
Iq (typ) (mA) 0.015 0.015
Ext Sync Yes Yes
Features OCP;OVP;PSM;Power Good;UVP OCP;OVP;PSM;Power Good;UVP
Package Type WQFN3x3-20 WQFN3x3-20
  • Support Connected Standby Mode for Ultrabook
  • CCRCOT Control with 100ns Load Step Response
  • PWM Maximum Duty Ratio > 98%
  • 5V to 25V Input Voltage Range
  • Dual Adjustable Output :
    ► CH1 : 2V to 5.5V
    ► CH2 : 2V to 4V
  • 5V/3.3V LDOs with 100mA Output Current
  • 1% Accuracy on 3.3V LDO Output
  • Oscillator Driving Output for Charge Pump Application
  • Internal Frequency Setting
    ► 300kHz/355kHz (CH1/CH2)
  • Internal Soft-Start and Soft-Discharge
  • 4700ppm/°C RDS(ON) Current Sensing
  • Independent Switcher Enable Control
  • Built-in OVP/UVP/OCP/OTP
  • Non-Latch UVLO
  • Power Good Indicator
  • RoHS Compliant and Halogen Free
TitleLast UpdateShareDownload
Dual-Channel Synchronous DC-DC Step-Down Controller with 5V/3.3V LDOs2013/10/28
Technical Documents
TitleLast UpdateShareDownload
Richtek Selection Guide [Oct., 2020]2020/12/30