The RT8059 is a high efficiency Pulse Width Modulated (PWM) step-down DC/DC converter, capable of delivering 1A output current over a wide input voltage range from 2.8V to 5.5V. The RT8059 is ideally suited for portable electronic devices that are powered by 1-cell Li-ion battery or by other power sources within the range, such as cellular phones, PDAs and handy-terminals.

Internal synchronous rectifier with low RDS(ON) dramatically reduces conduction loss at PWM mode. No external Schottky diode is required in practical applications. The RT8059 automatically turns off the synchronous rectifier when the inductor current is low and enters discontinuous PWM mode. This can increase efficiency in light load condition.

The RT8059 enters low dropout mode when normal PWM cannot provide regulated output voltage by continuously turning on the upper P-MOSFET. The RT8059 enters shutdown mode and consumes less than 0.1μA when the EN pin is pulled low.

The switching ripple can be easily smoothed out by small package filtering elements due to a fixed operation frequency of 1.5MHz. This along with small TSOT-23-5 package provides small PCB area application. Other features include soft-start, lower internal reference voltage with 2% accuracy, over temperature protection, and over current protection.


  • NIC Card
  • Cellular Telephones
  • Personal Information Appliances
  • Wireless and DSL Modems
  • MP3 Players
  • Portable Instruments
Key Spec.
Status Active
Vin (min) (V) 2.8
Vin (max) (V) 5.5
Number of Outputs 1
Vout (min) (V) 0.6
Vout (max) (V) 5.5
Output Adj. Method Resistor
Iout (max) (A) 1
Current Limit (typ) (A) 1.5
Freq (typ) (kHz) 1500
Ext Sync No
Ron_HS (typ) (mOhm) 280
Ron_LS (typ) (mOhm) 250
Iq (typ) (mA) 0.078
Features 100% Duty Cycle;Current Mode Control;Enable Input;Internal Compensation;OCP;OTP;PSM;Stable with Ceramic Capacitor
Package Type TSOT-25
  • Wide Input Voltage from 2.8V to 5.5V
  • Adjustable Output from 0.6V to VIN
  • 1A Output Current
  • 95% Efficiency
  • No Schottky Diode Required
  • 1.5MHz Fixed Frequency PWM Operation
  • Small TSOT-23-5 Package
  • RoHS Compliant and Halogen Free
TitleLast UpdateDownload
1.5MHz, 1A, High Efficiency PWM Step-Down DC/DC Converter2011/10/05
Additional Documents
Title Last Update ShareDownload
Power Management Components for Lithium-Ion Battery Powered Applications
Reference Design
TitleLast UpdateDownload
Richtek Load Transient Tool2022/07/25
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT8059GJ5TSOT-253000 Request Buy from Distributor