LTC4126-ADJ 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-ADJ is a low-power wireless single-cell Efficiency Multi-Mode Charge Pump DC/DC Li-Ion battery charger with an integrated step-down DC/ n Programmable Charge Current from 1mA to 50mA DC regulator. The step-down regulator is a low-noise multi- Via an External Resistor mode charge pump which is powered from the battery and n Wideband Rx Frequency: DC to >10MHz provides a regulated 1.2V at the output. The switching n Integrated Rectifier with Overvoltage Limit frequency is set to either 50kHz or 75kHz depending on the n Charge Voltage: 4.2V mode to keep any switching noise out of the audible range. n Low Battery Disconnect: 3.0V The constant-current constant-voltage Li-Ion battery n NTC Pin for Temperature Qualified Charging charger has automatic recharge, automatic termination n DC/DC Regulated Output: 1.2V by safety timer, and battery temperature monitoring via n DC/DC Output Current: Up to 60mA an NTC pin. Charge current is programmable from 1mA n 50kHz/75kHz Switching, No Audible Noise to 50mA via an external resistor. Undervoltage protection n Pushbutton and/or Digital on/off Control for DC/DC disconnects the battery from all loads when the battery n Thermally Enhanced 12-Lead 2mm 2mm LQFN voltage is below 3.0V. Package The small package and minimal external component count make the LTC4126-ADJ and its variants suitable for hear- APPLICATIONS ing aid applications and other low power portable devices. n See the chart below. Hearing Aids n Low Power Li-Ion Powered Devices PARAMETER LTC4126-ADJ LTC4126-10 LTC4126 n Wireless Headsets Charge Current Programmable 10mA 7.5mA n IoT Wearables Charge Timer 6 Hours 3 Hours 6 Hours Charge Voltage 4.2V 4.1V/4.2V 4.2V/4.35V EN Pin Polarity Active High Active Low Active High EN Pin Pull-Up N/A 1M N/A NTC Upper Threshold 76.5% of V 62% of V 76.5% of V CC CC CC V 3.2V 3.5V 3.2V LOBAT3 Threshold 1.1V 1.05V 1.1V DC/DC Mode 3 Timing 110ms 1.7s 110ms All registered trademarks and trademarks are the property of their respective owners. Top and Bottom View of the IC with TYPICAL APPLICATION Complete Application Circuit ACIN EN STAT1 C RX DIGITAL I/O STAT2 68nF AIR GAP ACPR V CC I = 7.5mA LTC4126-ADJ CHG BAT CHRG + Li-Ion L RX L TRANSMITTER 4.2V TX 8H NTC PROG + V IN OUT 1.2V R PROG TO BAT GND 2.2F 12.4k 4126-ADJ TA01 Rev. 0 1 Document Feedback For more information www.analog.comLTC4126-ADJ 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 PROG 4 7 ACIN 5 6 PBEN, NTC, EN, PROG .........................0.3V to Max (V , BAT) + 0.3V 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-ADJ TRPBF LHNJ e4 Au (RoHS) 3 20C to 85C with QFN Footprint) Consult Marketing 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-ADJ package dimension is 2mm 2mm 0.74mm compared to a standard QFN package dimension of 2mm 2mm 0.75mm. This product is 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 CHARACTERISTICS The 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 4.25 V BAT Not Charging, DC/DC On 3.1 4.25 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 = 4.25V 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. 0 2 For more information www.analog.com ACPR OUT CHRG V CC