The LTC1998 is a micropower comparator and a precision adjustable reference in a 6-pin SOT-23 package that is optimized for lithium-ion low battery detection circuits.The LTC1998 features a voltage detection circuit with an adjustable threshold voltage and hysteresis. The threshold voltage can be programmed from 2.5V to 3.25V with two external resistors. A 10mV to 750mV hysteresis can be added with a third external resistor.A proprietary internal architecture maintains 1% threshold voltage accuracy over temperature with low cost 1% external resistors.A separate power supply pin, VLOGIC, allows the battery-low logic output to operate below the battery voltage, allowing compatibility with low voltage microprocessors without a pull-up resistor. Power supply glitches are eliminated by preventing the cross-conducting current which occurs when the output changes state.The LTC1998 operates with battery or supply voltages up to 5.5V and its battery-low output is valid for battery voltages above 1.5V.ApplicationsLithium-Ion Battery-Powered EquipmentPDAsCell PhonesHandheld InstrumentsBattery PacksPagersPalm Top ComputersPOS Terminals