LTC4126

LTC4126 7.5mA Wireless Li-Ion Charger with 1.2V Step-Down DC/DC Converter FEATURES n Wireless Li-Ion Battery Charger Plus High Efficiency Multi-Mode Charge Pump DC/DC n Wideband Rx Frequency: DC to >10MHz n Integrated Rectifier with Overvoltage Limit n Pin Selectable Charge Voltage: 4.2V or 4.35V n Charge Current: 7.5mA (Fixed) n Low Battery Disconnect: 3.0V n NTC Pin for Temperature Qualified Charging n DC/DC Regulated Output: 1.2V n DC/DC Output Current: Up to 60mA n 50kHz/75kHz Switching, No Audible Noise n Pushbutton and/or Digital on/off Control for DC/DC n Thermally Enhanced 12-Lead 2mm × 2mm LQFN Package APPLICATIONS n Hearing Aids n Low Power Li-Ion Powered Devices n Wireless Headsets n IoT Wearables 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. The LTC4126 charger is a full-featured constant-current constant-voltage Li-Ion battery charger with automatic recharge, automatic termination by safety timer, and battery temperature monitoring via an NTC pin. Charge current is fixed at 7.5mA with a 6-hour termination timer. Undervoltage protection disconnects the battery from all loads when the battery voltage is below 3.0...