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Comparator draws zero current

San Jose, Calif. — Micrel Inc. claims this precision micro-power battery monitor/comparator with an on-chip 2.55-V reference voltage source features an extremely low supply current and draws virtually zero current from a battery or monitored voltage source.

Made for sensing and indicating end of life in Lithium batteries, the MIC845 fulfills the UL's isolation requirements between primary batteries and power sources while consuming a mere 5 picoamps of sense current from the battery, said Bob Whelton, Micrel's executive vice president operations. Operating from just a 1.5 μA supply current, the comparator requires no resistor divider for proper voltage level detection, he said.

Intended for voltage monitoring applications, the MIC845 can be used with an external resistor divider to detect a wide range of voltages, or without external resistors to directly monitor voltages with its high input impedance CMOS input.

The MIC845 incorporates a voltage reference and comparator with fixed internal hysteresis. When the 2.55-V internal threshold is crossed, the output switches polarity.

The MIC845 is available with a push-pull or open-drain output stage. The push-pull output stage is configured for both active high or active low output; the open-drain output stage is only configured active high.

Supply current is extremely low (typically 1 μA), making it attractive for portable applications, including PDAs, pagers, cordless phones, portable electronics, motherboards and bladed servers.

Offered in a SC-70 package, the IC is currently available in volume quantities with pricing starting at 40 cents each in 1K quantities. Click here for the MIC845 data sheet.

Micrel , 1-408-944-0800, www.Micrel.com.

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