LTC4425EMSE#PBF

LTC®4425 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 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. The voltage on the PROG pin represents the current flowing from VIN to VOUT for current monitoring. Typical applications are high peak power battery/USB powered equipment, industrial PDAs, portable instruments/monitoring equipment, power meters, SuperCap backup circuits, PC card/USB modems.

• Charge current (VOUT current limit) is programmed by connecting a resistor between PROG and GND
• Smart charge current profile limits inrush current, 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
• Quiescent current from VIN is 20µA typical (VIN=VOUT, TA=25°C, VIN=3.8V)
• Quiescent current in shutdown is 3µA maximum (EN=0, TA=25°C, VIN=3.8V)
• Feedback pin input leakage is 100nA (TA=25°C, VIN=3.8V)
• 12-lead plastic MSOP package
• Temperature rating range from -40°C to 125°C

Notes

ADI products are only authorized (and sold) for use by the customer and are not to be resold or otherwise passed on to any third party