National Semi Intros LM3658 AC Battery Charger and IC
National Semiconductor Corp. (Santa Clara, CA) introduced its new LM3658, a dual-input, USB/ac battery charger and power-management IC designed for single-cell, lithium-ion/polymer battery applications as well as a variety of portable devices including personal digital assistants, MP3 players, digital still cameras, Internet appliances, instrumentation and smart phones.
The chip features high accuracy for the charge-terminating voltage (within 1.5% of 4.2 V) to extend battery life. Advanced management circuitry keeps tabs on thermal regulation and battery temperature, and multiple safety timers minimize the chance for runaway conditions. The LM3658 provides two open-drain outputs for LED status indication or connection to general-purpose input/outputs. In basic operation, the chip steps through five operating modes: pre-qualification; constant-current; constant-voltage; top-off; and maintenance. The LM3658 delivers a charge current from 50 mA to 1 A (programmed by a single resistor) when operating from an ac wall adapter. It delivers a pin-selectable 100 mA or 500 mA when the battery is charged from a USB source. The LM3658, working from a 2.5 V to 6 V input, defaults automatically to the ac wall adapter setting when both power sources are present.
The LM3658, packaged in a thermally enhanced, 10-lead LLP, is priced at $1.50 each in 1,000-unit quantities. An evaluation board and lead-free package options are also available.
