Microchip Technology, Inc. Voltage Monitor with Adjustable Hysteresis MIC2778

The MIC2779 is a voltage monitor--uniquely designed to detect two separate voltage thresholds--combined with a delay generator and logic. It is designed for monitoring the battery supply of portable digital systems, particularly PDAs, pagers, and cellular telephones. High and low voltage thresholds can be adjusted independently, allowing for wide hysteresis. Voltage detection thresholds are accurate to 2%. If the battery voltage falls below the low-voltage threshold, the output /RST or RST is asserted and latched, preventing system operation until the battery is replaced or recharged. Internal logic prevents the output from chattering due to battery recovery or load removal. The output is asserted for 140ms (minimum) when a fresh battery is inserted. For applications requiring open-drain output, see MIC2778/MIC833. The IC's power supply input is separate from the detector inputs, allowing the MIC2779 to be powered from a downstream supply, such a boost converter. Supply current is extremely low (1µA, typical), making it ideal for portable applications. A high-precision 1% grade is available. The MIC2779 is supplied in IttyBitty™ 5-lead SOT-23-5 package. Additional Features Optimized for PDAs, cellular telephones, pagers, and other battery-powered devices Independently adjustable high- and low-voltage thresholds Internal logic prevents battery-voltage-fluc tuation chatter High ±2% voltage threshold accuracy; 1% available Built in 140ms (minimum) delay deglitches output Extremely low 1µA typical supply current For applications requiring open-drain output, see MIC2778/MIC833 Immune to brief power supply transients 5-lead SOT-23 package