New Industry Products

LTC Intros LTC4076/LTC4077 Standalone Battery Chargers

October 01, 2005 by Jeff Shepard

Linear Technology Corp. (LTC, Milpitas, CA) introduced the new LTC4076 and LTC4077 standalone, dual-input, linear battery chargers, which charge single-cell, lithium-ion batteries from wall adapter or USB power sources. The LTC4076 and LTC4077 use a constant-current/constant-voltage algorithm for charging, with charge current programmable up to 950 mA from a wall adapter supply, or programmable up to 650 mA from a USB supply, while automatically sensing the presence of voltage at each input.

The LTC4076 features programmable C/x charge current termination, while the LTC4077 offers fixed C/10 termination. The LTC4076 features a choice of fixed C or C/5 USB charge current for low-power USB operation (via the HPWR pin) and the LTC4077 offers programmable C or C/x low-power USB charge current (via the HPWR pin). Applications include PDAs, MP3 players, digital cameras, lightweight portable medical and test equipment, and large-color screen cell phones.

The LTC4076 and LTC4077 feature final float voltage accuracy of 0.6 percent and are equipped with a patented thermal regulation scheme that maximizes the charging rate without the risk of overheating. The devices are extremely flexible with a wall adapter supply charge current, USB supply charge current, and charge termination currents programmable via a single resistor. As standalone chargers, they also feature trickle charge for battery pre-conditioning, under-voltage lockout, automatic recharge, a charge status indicator, and "power-present" status outputs to indicate the presence of wall adapter or USB power.

The LTC4076 and LTC4077 are offered in a low-profile (0.75 mm), 10-lead, 3 mm x 3 mm DFN package. The total solution footprint is less than 25 mm² since no external MOSFET, sense resistors, or blocking diodes are required. To preserve battery energy, the LTC4076 and LTC4077 draw <6 µA from the battery terminal in standby and <2 µA in shutdown mode. The LTC4076 and LTC4077 are rated for operation from -40 °C to +85 °C. Pricing for 1,000-piece quantities begins at $1.88 each.