DESCRIPTION
The LTC®4126 is a low-power wireless single-cell Li-Ion battery charger with an integrated step-down DC/DC regulator. The step-down regulator is a low-noise multi-mode charge pump which is powered from the battery and provides a regulated 1.2V at the output. The switching frequency is set to either 50kHz or 75kHz depending on the mode to keep any switching noise out of the audible range.

FEATURES
■ Wireless Li-Ion Battery Charger Plus High
   Efficiency Multi-Mode Charge Pump DC/DC
■ Wideband Rx Frequency: DC to >10MHz
■ Integrated Rectifier with Overvoltage Limit
■ Pin Selectable Charge Voltage: 4.2V or 4.35V
■ Charge Current: 7.5mA (Fixed)
■ Low Battery Disconnect: 3.0V
■ NTC Pin for Temperature Qualified Charging
■ DC/DC Regulated Output: 1.2V
■ DC/DC Output Current: Up to 60mA
■ 50kHz/75kHz Switching, No Audible Noise
■ Pushbutton and/or Digital on/off Control for DC/DC
■ Thermally Enhanced 12-Lead 2mm × 2mm
   LQFN Package

APPLICATIONS
■ Hearing Aids
■ Low Power Li-Ion Powered Devices
■ Wireless Headsets
■ IoT Wearables