3A, Ultra-Low Dropout Voltage Regulator


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The RT9059B is a high performance positive voltage regulator designed for use in applications requiring very low input voltage and very low dropout voltage at up to 3A. It operates with a VIN as low as 1V and VDD voltage 3V with programmable output voltage as low as 0.8V. The RT9059B features ultra low dropout, ideal for applications where VOUT is very close to VIN. Additionally, it has an enable pin to further reduce power dissipation while shutdown. The RT9059B provides excellent regulation over variations in line, load and temperature. The RT9059B provides a power good signal to indicate if the voltage level of VO reaches 90% of its rating value.


  • Notebook PC Applications
  • Motherboard Applications
Key Spec.
Status Active
Vin (min) (V) 1
Vin (max) (V) 5.5
Vout (min) (V) 0.8
Vout (max) (V) 4
Output Adj. Method Resistor
Accuracy (+/- %) 1
Iout (max) (mA) 3000
Iq (typ) (uA) 600
Vdropout @ rated current (typ) (mV) 250 @ 2A;350 @ 3A
Bias Rail Yes
Cout Type Ceramic
Charge Pump No
Features Enable Input;OCP;Power Good;Stable with Ceramic Capacitor
Package Type WDFN3x3-10
  • Output Current up to 3A
  • High Accuracy ADJ Voltage 1%
  • Dropout Voltage 350mV @ 3A Typically
  • VOUT Power Good Signal
  • VOUT Pull Low Resistance when Disable
  • Current Limiting Protection
  • Thermal Shutdown Protection
  • RoHS Compliant and Halogen Free
TitleLast UpdateShareDownload
3A, Ultra-Low Dropout Voltage Regulator2018/08/28
Technical Documents
TitleLast UpdateShareDownload
Richtek Selection Guide [Oct., 2020]2020/12/30