LT LTC4425IMSE#PBF

Суперконденсаторное зарядное устройство20 мкА2,7 В ~ 5,5 В

Overview

The LTC4425IMSE 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 50mΩ on-resistance making it suitable for high peak-power/low average power applications. The LTC4425IMSE 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 the LTC4425IMSE 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. The voltage on the PROG pin represents the current fl owing from VIN to VOUT for current monitoring. An internal active balancing circuit maintains equal voltages across each supercapacitor and clamps the peak voltage across each cell to a pin-selectable maximum value. The LTC4425IMSE operates at a very low 20μA quiescent current (shutdown current <3μA) and is available in a low profile 12-pin 3mm × 3mm DFN or a 12-lead MSOP package.

Features

Applications

• SmartPhones
• Portable Navigation Devices
• Portable Media Players
• Portable Systems
• Hand-Held Systems
• Space satellite point of load supply
• Communications payload
• Optical imaging payload
• Desktop PC
• Motherboard