The PT7M6838 are microprocessor (μP) supervisory circuits used to monitor low-voltage power supplies in μP and digital systems.
They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +1.2V to +1.8V powered circuits. The accuracy of detect voltage is 1.5%. The device asserts a reset signal whenever the VCC supply voltage declines below a preset threshold or whenever manual reset (/MR) is asserted. Reset remains asserted for a fixed timeout delay after VCC has risen above the reset threshold or when manual reset is deasserted. Five different timeout periods are available: 70μs (voltage detector), 1.5ms, 30ms, 210ms, and 1.68s. Reset thresholds suitable for operation with a variety of supply voltages are available. The PT7M6838 has a push-pull active-low reset output (/RESET). The open-drain active-low reset output requires a pull-up resistor that can be connected to a voltage higher than VCC. It provides a RESET-IN input allowing the user to externally adjust the reset threshold. The reset comparator is designed to ignore fast transients on VCC. Low supply current of 7.5μA makes the PT7M6838 ideal for use in portable equipment.
The device is available in small 4-pin SC70 package.
