The RT6211A/B is a high-efficiency, monolithic synchronous step-down DC/DC converter that can deliver up to 1.5A output current from a 4.5V to 18V input supply. The RT6211A/B adopts ACOT architecture to allow the transient response to be improved and keep in constant frequency. Cycle-by-cycle current limit provides protection against shorted outputs and soft-start eliminates input current surge during start-up. Fault conditions also include output under voltage protection, output over current protection, and thermal shutdown.


  • Set-Top Boxes
  • Portable TVs
  • Access Point Routers
  • DSL Modems
  • LCD TVs
Key Spec.
RT6211A RT6211B
Status Active Active
Vin (min) (V) 4.5 4.5
Vin (max) (V) 18 18
Number of Outputs 1 1
Vout (min) (V) 0.8 0.8
Vout (max) (V) 6.5 6.5
Output Adj. Method Resistor Resistor
Iout (max) (A) 1.5 1.5
Current Limit (typ) (A) 2.5 2.5
Freq (typ) (kHz) 520 520
Ext Sync No No
Ron_HS (typ) (mOhm) 230 230
Ron_LS (typ) (mOhm) 130 130
Iq (typ) (mA) 0.8 0.8
Features ACOT Control;Cycle-by-Cycle Current Limit;Enable Input;Internal Compensation;OCP;OTP;PSM;SCP;Stable with Ceramic Capacitor;UVP ACOT Control;Cycle-by-Cycle Current Limit;Enable Input;Force PWM;Internal Compensation;OCP;OTP;SCP;Stable with Ceramic Capacitor;UVP
Package Type SOT-26 SOT-26
  • Integrated 230mΩ/130mΩ MOSFETs
  • 4.5V to 18V Supply Voltage Range
  • 500kHz Switching Frequency
  • ACOT Control
  • 0.8V ± 1.5% Voltage Reference
  • Internal Start-Up from Pre-biased Output Voltage
  • Compact Package : SOT-23-6 pin
  • High/Low Side Over-Current Protection and Hiccup
  • VOUT Range 0.8V to 6.5V
TitleLast UpdateDownload
1.5A, 18V, 500kHz, ACOT® Step-Down Converter2016/12/28
Reference Design
TitleLast UpdateDownload
Richtek Load Transient Tool2022/07/25