LTC1998 2.5µA, 1% Accurate SOT-23 Comparator and Voltage Reference for Battery Monitoring FEATURESDESCRIPTION n High Accuracy Trip Voltage: 1% Max Error Using The LTC®1998 is a micropower comparator and a precision External 1% Resistors adjustable reference in a 6-pin SOT-23 package that is n Adjustable Threshold Voltage and Hysteresis optimized for lithium-ion low battery detection circuits. n Quiescent Current: 2.5μA Typ The LTC1998 features a voltage detection circuit with an n Output Swings Rail-to-Rail adjustable threshold voltage and hysteresis. The threshold n Thresholds Programmable from 2.5V to 3.25V voltage can be programmed from 2.5V to 3.25V with two n Output State Guaranteed for VBATT ≥1.5V external resistors. A 10mV to 750mV hysteresis can be n Low Profi le (1mm) ThinSOT™ Package added with a third external resistor. APPLICATIONSA proprietary internal architecture maintains 1% thresh- old voltage accuracy over temperature with low cost 1% n Lithium-Ion Battery-Powered Equipment external resistors. PDAs A separate power supply pin, VLOGIC, allows the battery-low Cell Phones logic output to operate below the battery voltage, allowing Handheld Instruments compatibility with low voltage microprocessors without a Battery Packs pull-up resistor. Power supply glitches are eliminated by Pagers preventing the cross-conducting current which occurs Palm Top Computers when the output changes state. POS Terminals The LTC1998 operates with battery or supply voltages L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other up to 5.5V and its battery-low output is valid for battery trademarks are the property of their respective owners. voltages above 1.5V. BLOCK DIAGRAMThreshold Voltage Error vs Temperature 1.0 BATT 0.9 V V LOGIC 0.8 TH.A SET BY 1% EXTERNAL R, 0.7 THRESHOLD = 3V 1.1R 0.6 VHYST.A THRESHOLD 0.5 VTH.A = 1V ADJUST R BATTLO THRESHOLD = 3V % ERROR 0.4 VTH.A V 0.3 TH.A SHORTED TO GROUND, 1.2V 0.2 THRESHOLD = 2.5V 0.1 0 1998 BD –45 –25 –5 15 35 55 75 95 TEMPERATURE (°C) 1998 TA02 1998fb 1
