LTC4126 7.5mA Wireless Li-Ion Charger with 1.2V Step-Down DC/DC Converter FEATURES DESCRIPTION n Wireless Li-Ion Battery Charger Plus High The LTC 4126 is a low-power wireless single-cell Li-Ion Efficiency Multi-Mode Charge Pump DC/DC battery charger with an integrated step-down DC/DC regu- n Wideband Rx Frequency: DC to >10MHz lator. The step-down regulator is a low-noise multi-mode n Integrated Rectifier with Overvoltage Limit charge pump which is powered from the battery and pro- n Pin Selectable Charge Voltage: 4.2V or 4.35V vides a regulated 1.2V at the output. The switching fre- n Charge Current: 7.5mA (Fixed) quency is set to either 50kHz or 75kHz depending on the n Low Battery Disconnect: 3.0V mode to keep any switching noise out of the audible range. n NTC Pin for Temperature Qualified Charging The LTC4126 charger is a full-featured constant-current n DC/DC Regulated Output: 1.2V constant-voltage Li-Ion battery charger with automatic n DC/DC Output Current: Up to 60mA recharge, automatic termination by safety timer, and bat- n 50kHz/75kHz Switching, No Audible Noise tery temperature monitoring via an NTC pin. Charge cur- n Pushbutton and/or Digital on/off Control for DC/DC rent is fixed at 7.5mA with a 6-hour termination timer. n Thermally Enhanced 12-Lead 2mm 2mm Undervoltage protection disconnects the battery from all LQFNPackage loads when the battery voltage is below 3.0V. The tiny 2mm 2mm LQFN package and minimal external APPLICATIONS component count make the LTC4126 well suited for Li-Ion n Hearing Aids battery powered hearing aid applications and other low power n Low Power Li-Ion Powered Devices portable devices where a small solution size is required. n Wireless Headsets All registered trademarks and trademarks are the property of their respective owners. n IoT Wearables TYPICAL APPLICATION Top and Bottom View of the IC with Complete Application Circuit EN ACIN C STAT1 RX DIGITAL I/O 68nF STAT2 AIR GAP V CC ACPR LTC4126 BAT + Li-Ion CHRG L RX TRANSMITTER L TX 4.2V 8H NTC V + V SEL IN OUT 1.2V GND 2.2F 4126 TA01 TO BAT Rev. A 1 Document Feedback For more information www.analog.comLTC4126 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 2) TOP VIEW Input Supply Voltages V ........................................................... 0.3V to 6V CC ACIN ..........................................................10V to 6V 12 11 NTC 1 10 STAT1 ACIN V Differential ...........................16V to 0.3V CC EN 2 9 STAT2 Input/Output Currents 13 I ................................................................ 200mA GND ACIN PBEN 3 8 BAT I ................................................................. 60mA OUT BAT .............................................................. 0.3V to 6V V 4 7 ACIN SEL 5 6 PBEN, NTC, EN, V ...........................0.3V to Max (V , BAT) + 0.3V SEL CC CHRG ........................................................... 0.3V to 6V LQFN PACKAGE 12-LEAD (2mm 2mm 0.74mm) Operating Junction Temperature Range ... 20C to 85C T = 85C, = 92C/W JMAX JA EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB Storage Temperature Range .................. 40C to 125C Maximum Reflow (Package Body) Temperature ..........................................................260C ORDER INFORMATION TAPE AND REEL PACKAGE** MSL PART NUMBER PART MARKING* FINISH CODE PAD FINISH TYPE RATING TEMPERATURE RANGE LQFN (Laminate Package LTC4126EV TRPBF LHCP e4 Au (RoHS) 3 20C to 85C with QFN Footprint) Contact the factory for parts specified with wider operating temperature ranges. *Device temperature grade is identified by a label on the shipping container. Parts ending with PBF are RoHS and WEEE compliant. **The LTC4126 package dimension is 2mm 2mm 0.74mm compared to a standard QFN package dimension of 2mm 2mm 0.75mm. This product only available in tape and reel or in mini-reel. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. ELECTRICAL CHARACTERISTICSThe l denotes the specifications which apply over the specified operating temperature range, otherwise specifications are at T = 25C (Notes 2, 3). V = V = 5V, V = 3.8V, unless otherwise noted. A ACIN CC BAT SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS l V Input Voltage Range 2.7 5.5 V CC V Battery Voltage Range Charging 2.7 4.4 V BAT Not Charging, DC/DC On 3.1 4.4 V I V Quiescent Current Charging Done, DC/DC Off, V > V 50 80 A VCC CC NTC DIS Charging Done, DC/DC Off, V < V 42 70 A NTC DIS I BAT Quiescent Current Charging Done, DC/DC Off, V = 4.4V 4 8 A BATQ BAT V = V = 0, DC/DC On, I = 0 37 75 A ACIN CC OUT V = V = 0, DC/DC Off 5 10 A ACIN CC V = V = 0, Battery Disconnected 0 0.1 A ACIN CC (V < V ) BAT DISCONNECT Rev. A 2 For more information www.analog.com ACPR OUT CHRG V CC