The RT9085A is a high-performance positive voltage regulator with separated bias voltage (VBIAS), designed for applications requiring low input voltage and ultra low dropout voltage, output current up to 1A. The feature of ultra low dropout voltage is ideal for applications where output voltage is very close to input voltage. The input voltage can be as low as 0.8V and the output voltage is adjustable by an external resistive divider. The RT9085A features very low quiescent current consumption for portable applications. The device is available in the WL- CSP-6B 0.8x1.2 (BSC) package.


  • Battery Powered Systems
  • Portable Electronic Device
  • Digital Set Top Boxes
Key Spec.
Status Active
Vin (min) (V) 0.8
Vin (max) (V) 5.5
Vout (min) (V) 0.5
Vout (max) (V) 3.9
Output Adj. Method Fixed;Resistor
Accuracy (+/- %) 1
Iout (max) (mA) 1000
Iq (typ) (uA) 35
Vdropout @ rated current (typ) (mV) 60 @ 1A
Bias Rail Yes
Cout Type Ceramic
Charge Pump No
Features Enable Input;Low Dropout;OCP;Stable with Ceramic Capacitor
Package Type WL-CSP0.8x1.2-6(BSC)
  • Input Voltage Range: 0.8V to 5.5V
  • Bias Voltage Range: 3V to 5.5V
  • Available in Fixed and Adjustable (0.5V to 3V)
  • Ultra Low Dropout Voltage: 60mV at 1A
  • Accurate Output Voltage Accuracy Over Line/Load/Temperature
    ► 1% @ -40°C to 85°C
    ► 2% @ -40°C to 125°C
  • Low Bias Input Current
    ► Typ 35μA in Operating Mode
    ► Typ 0.5μA in Shutdown Mode
  • Output Active Discharge Function
  • Enable Control
  • Stable with a 10μF Output Ceramic Capacitor
TitleLast UpdateDownload
1A, 5.5V, Ultra Low Dropout Linear Regulator2018/03/14
Technical Documents
TitleItem TypeLast UpdateDownload
Richtek Product Selection Guide [Jan., 2024] Selection Guide2024/01/18
Power Management for Video Doorbell App. Note2021/10/08
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT9085AWSCWL-CSP0.8x1.2-6(BSC)3000 Request Buy from Distributor