The RT9450A is a low cost switch-mode single cell Li-ion and Li-polymer battery charger for portable applications. It integrates a synchronous PWM controller, power MOSFETs, input current sensing, high accuracy current and voltage regulation, and charge termination into a small package for space-limited devices. The RT9450A also features USB On-The-Go (OTG).

The RT9450A optimizes the charging task by using a control algorithm to vary the charge rate via different modes, including preconditioning mode, fast charge mode, and constant voltage mode. All charge parameters can be executed via the I2C interface. Some of these parameters include a user-selectable minimum current level setting for charge termination, a safety timer with reset control to provide safety backup for I2C interface, and charge status indication to the host. During normal operation, the RT9450A automatically restarts the charge cycle whenever the battery voltage falls below an internal threshold and automatically enters sleep mode when the input supply is removed.

Other features include under voltage protection, over voltage protection, thermal regulation and protection, and reverse leakage protection.

The RT9450A is available in a small WL-CSP-20B 2x2 (BSC) package.


  • Mobile Phones & Smart Phones
  • MP3 Players
  • Handheld Devices
Key Spec.
Status NRND
Recommended Alternative  RT9470/RT9470D
Vin (min) (V) 4
Vin (max) (V) 6
Battery Charge Voltage (max) (V) 4.45
Battery Charge Current (max) (A) 1.5
Status Indicator Yes
Charger Type Switching
Input Source AC Adapter;USB
Features Current Mode Control;Cycle-by-Cycle Current Limit;OCP;OVP;UVP
Package Type WL-CSP2x2-20
Built-in Power MOSFETs Yes
  • Support USB On-The-Go (OTG)
  • High Accuracy Voltage and Current Regulation
  • Average Input Current Regulation (AICR) : 100mA, 400mA, 1000mA
  • Charge Voltage Regulation Accuracy : ±1% (0°C to 85°C)
  • Charge Current Regulation Accuracy : ±5%
  • Hi-Efficiency USB/AC Battery Charger for Single Cell Li-Ion Battery
  • Built-in Input Current Sensing and Limiting
  • Integrated Power MOSFETs
  • Synchronous 3MHz Fixed Frequency PWM Controller with up to 99.5% Duty Cycle
  • Reverse Leakage Protection to Prevent Battery Drainage
  • Thermal Regulation and Protection
  • Input Over Voltage Protection
  • Status Output for Charging and Faults
  • Automatic Charging
  • RoHS Compliant and Halogen Free
TitleLast UpdateDownload
Switch-Mode Single Cell Li-Ion Battery Charger with USB-OTG2013/01/24
Additional Documents
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Power Management Components for Lithium-Ion Battery Powered Applications