2.5MHz, Synchronous Boost Regulator with Bypass Mode


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The RT4803 allows systems to take advantage of new battery chemistries that can supply significant energy when the battery voltage is lower than the required voltage for system power ICs. By combining built-in power transistors, synchronous rectification, and low supply current; this IC provides a compact solution for systems using advanced Li-Ion battery chemistries.

The RT4803 is a boost regulator designed to provide a minimum output voltage from a single-cell Li-Ion battery, even when the battery voltage is below system minimum. In boost mode, output voltage regulation is guaranteed to a maximum load current of 2A. Quiescent current in Shutdown Mode is less than 1μA, which maximizes battery life. The regulator transitions smoothly between Bypass and normal Boost Mode. The device can be forced into Bypass Mode to reduce quiescent current.

The RT4803 is available in the WL-CSP-16B 1.67x1.67 (BSC) package.


  • Single-Cell Li-Ion, LiFePO4 Smart-Phones or Tablet
  • 2.5G/3G/4G Mini-Module Data Cards
Key Spec.
Status Active
Vin (min) (V) 1.8
Vin (max) (V) 5.0
Vout (min) (V) 2.85
Vout (max) (V) 4.4
Output Adj. Method Digital
Iq (typ) (mA) 0.065
SW Current Limit (typ) (A) 5
Freq (typ) (kHz) 2500
Interface I2C
Features Adjustable Current Limit;Current Mode Control;Cycle-by-Cycle Current Limit;Enable Input;Internal Compensation;OCP;OVP;Power Good;UVP
Package Type WL-CSP1.67x1.67-16(BSC)
  • 4 Few External Components: 0.47μH Inductor and 0603 Case Size Input and Output Capacitors
  • Input Voltage Range: 1.8V to 5V
  • Output Range from 2.85V to 4.4V
    ► VSEL = L 3.3V
    ► VSEL = H 3.55V
  • Maximum Continuous Load Current: 2A at VIN > 2.65V Boosting VOUT to 3.35V
  • Up to 96% Efficient
  • True Bypass Operation when VIN > Target VOUT
  • Internal Synchronous Rectifier
  • Soft-Start with True Load Disconnect
  • Forced Bypass Mode
  • VSEL Control to Optimize Target VOUT
  • Short-Circuit Protection
  • I2C Controlled Interface
  • Ultra low Operating Quiescent Current
  • Small WL-CSP 16B Package
  • Discharge Function
TitleLast UpdateShareDownload
2.5MHz, Synchronous Boost Regulator with Bypass Mode2015/05/20
Technical Documents
TitleLast UpdateShareDownload
Power IC Solutions for IoT/Portable/Wearable/Battery-Powered Applications2020/12/30
Richtek Selection Guide [Oct., 2020]2020/12/30
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT4803WSCWL-CSP1.67x1.67-16(BSC)3000 Request Buy from Distributor