LTC3226 2-Cell Supercapacitor Charger with Backup PowerPath Controller FEATURES DESCRIPTION n 1x/2x Multimode Charge Pump Supercapacitor The LTC 3226 is a 2-cell series supercapacitor charger with Charger a backup PowerPath controller. It includes a charge pump n Automatic Cell Balancing supercapacitor charger with programmable output voltage, n Ideal Diode Main PowerPath Controller a low dropout regulator, and a power-fail comparator for (V to V ) switching between normal and backup modes. IN OUT n Internal 2A LDO Backup Supply (CPO to V ) OUT The constant input current supercapacitor charger is n Automatic Main/Backup Switchover designed to charge two supercapacitors in series to a n Input Voltage Range: 2.5V to 5.5V resistor-programmable output voltage of 2.5V to 5.3V. n Programmable SCAP Charge Voltage The charger input current limit is programmable by an n Programmable Input Current Limit (315mA Max) external resistor at up to 315mA. n No Load I = 55A (Typical) VIN n The internal backup LDO is powered from the superca- Low Profile, 16-Lead 3mm 3mm QFN Package pacitors and provides up to 2A peak output current with APPLICATIONS an adjustable output voltage. When the input supply falls below the power-fail threshold, the LTC3226 automatically n Smart Power Meters enters a backup state in which the supercapacitors power n Battery-Powered Industrial/Medical Equipment the output through the LDO. The input supply power-fail n 3.3V Solid-State Drives voltage level is programmed by an external resistor divider. n Industrial Alarms n Data Backup Supplies Low input noise, low quiescent current and a compact n Battery Hold-Up Supplies footprint make the LTC3226 ideally suited for small, battery- L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks powered applications. Internal current limit and thermal and PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the shutdown circuitry allow the device to survive a continu- property of their respective owners. ous short-circuit from the PROG or CPO pins to ground. TYPICAL APPLICATION 3.3V Backup Supply MPEXT TO LOAD Automatic Normal-to-Backup (2A) Mode Switchover LTC3226 V IN GATE V 6 IN 3.3V C = 1.2F LDO SC V 2.2F OUT CPO C = 47F OUT 5 I = 2A LOAD C OUT 255k 47F 1.96M LDO FB 4 V OUT RST FB 80.6k 3 1.2V + CPO 5V V IN PFI 2 + V BACKUP 1.21M IN C VMID C SC BACKUP MODE MODE 1.2F 1 (LDO IN 2.2F (LDO IN C CHARGE DROPOUT) REGULATION) PROG PUMP 0 3.83M PFO (2V/DIV) EN CHG CPO FB 33.2k 1 0 0.4 0.8 1.2 1.6 2.0 PFO 1.21M TIME (SECONDS) RST CAPGOOD 3226 TA01b GND 3226 TA01a 3226fa 1 VOLTAGE (V)LTC3226 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , V , VMID, CPO, RST, PFO, IN OUT CAPGOOD, LDO FB ..................................... 0.3V to 6V 16 15 14 13 EN CHG, PFI, RST FB, V 1 12 C OUT CPO FB Voltage ............0.3V to Max (V , CPO) + 0.3V IN PFO 2 11 CAPGOOD 17 Operating Junction Temperature Range GND PFI 3 10 CPO FB (Note 3) ...................................................... 40 to 125C LDO FB 4 9 PROG Storage Temperature Range ......................65 to 150C 5 6 7 8 UD PACKAGE 16-LEAD (3mm w 3mm) PLASTIC QFN T = 125C, = 58.7C/W (NOTE 2) JMAX JA EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3226EUD PBF LTC3226EUD TRPBF LFZV 16-Lead (3mm 3mm) Plastic QFN 40C to 125C LTC3226IUD PBF LTC3226IUD TRPBF LFZV 16-Lead (3mm 3mm) Plastic QFN 40C to 125C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: