ANALOG DEVICES LTC4425EDD#PBF Linear Charger, Constant Current/Voltage, Li-Ion/Polymer, 2.7 to 5.5 V, -40 to 125 Deg C, DFN-EP-12

LTC4425 is a constant-current/constant-voltage linear charger designed to charge a 2-cell supercap stack from either a Li-Ion/polymer battery, a USB port, or a 2.7V to 5.5V current-limited supply. The part operates as an ideal diode with an extremely low 50Mohm on-resistance making it suitable for high peak-power/low average power applications. This device charges the output capacitors to an externally programmed output voltage in LDO mode at a constant charge current, or to VIN in normal mode with a smart charge current profile to limit the inrush current until the VIN to VOUT differential is less than 250mV. In addition it can be set to clamp the output voltage to 4.9V or 5.4V. Charge current (VOUT current limit) is programmed by connecting a resistor between PROG and GND. It is used in applications such as high peak power battery/USB powered equipment, industrial PDAs, portable instruments/monitoring equipment, power meters, supercap backup circuits, PC card/USB modems etc.

• Internal cell balancer (no external resistors)
• Programmable output voltage (LDO mode)
• Programmable VIN to VOUT current limit
• Continuous monitoring of VIN to VOUT current via PROG pin
• VIN power fail, PGOOD indicator
• 3A peak current limit, thermal limiting
• Low quiescent current is 20μA typical at (VIN = VOUT, TA = 25°C, VIN = 3.8V)
• Quiescent current in shutdown is 3µA maximum at (EN = 0, TA = 25°C, VIN = 3.8V)
• Operating temperature is -40°C to 125°C
• Package style is 12-lead plastic DFN