MIC2755

The MIC2755 is composed of multiple comparators, a reset pulse generator, and logic. It is designed for monitoring the battery supply of portable digital systems, including PDAs and pagers.

The MIC2755 detects three different battery states: battery OK, low battery, and dead battery. The reset (/RST) output is asserted for at least 700ms when a fresh battery is inserted. The nonmaskable interrupt output (/NMI) is asserted when the battery voltage is below the NTH threshold, indicating that high-power system operations should not occur. If and when battery voltage falls below the power-off threshold (PTH), the reset output is asserted and latched, inhibiting system operation until the battery is replaced or recharged.

All three voltage thresholds are set using external resistors. A manual reset function can be implemented by connecting a switch directly to the power on reset/manual reset [RTH(/MR)] input. Internal circuitry detects switch activation and generates a minimum 175ms debounced reset signal. The MIC2755's power supply input is separate from the detector inputs to allow it to be powered from a down-stream voltage, such as the output of a boost converter.

Inputs and outputs can be pulled above V_DD (up to 7V absolute maximum) without adverse effects or excessive current draw.

Supply current is typically a low 2A. Hysteresis is included on all voltage detectors to prevent chattering due to noise. The MIC2755 is available in the tiny 8-lead micro-smalloutline package.