MIC2778 Micrel MIC2778
Voltage Monitor with Adjustable Hysteresis General Description Features The MIC2778 is a voltage monitorвЂ”uniquely designed to
detect two separate voltage thresholdsвЂ”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) 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
not requiring built-in delay, see MIC841.
The ICвЂ™s power supply input is separate from the detector
inputs, allowing the MIC2778 to be powered from a downstream supply, such a boost converter. Supply current is
extremely low (1ВµA, typical), making it ideal for portable
A high-precision 1% grade is available. The MIC2778 is supplied in MicrelвЂ™s IttyBittyв„ў 5-lead SOT-23-5 package. Optimized for PDAs, cellular telephones, pagers,
and other battery-powered devices Independently adjustable high-and
low-voltage thresholds Internal logic prevents battery-voltage-п¬‚uctuation chatter High В±2% voltage threshold accuracy; 1% available Built in 140ms (minimum) delay deglitches output Extremely low 1ВµA typical supply current For applications not requiring built-in delay, see MIC841 Immune to brief power supply transients 5-lead SOT-23 package Applications PDAs