Microprocessor Supervisory Circuits Reduce Power Requirements For Portable Consumer, Communications And Industrial Appliances

The new circuits provide a low-power option for the precision monitoring of DSP, ASIC, FPGA and other processor power supplies to detect under-voltage conditions that can lead to system failure. The supervisory ICs monitor 2.5-V, 3-V, 3.3-V, and 5-V voltage rails. The ADM6326, ADM6328, ADM6346 and ADM6348 provide a reset output during power-up, power-down and brownout conditions. On power-up, an internal timer holds reset asserted for at least 100 ms, which effectively holds the microprocessor in a reset state until conditions have stabilised.



The ADM6326 and ADM6346 have an active low push-pull reset output. The ADM6328 and ADM6348 have an active low open-drain output, which requires an external pull-up resistor. The reset output remains operational with Vcc as low as 1 V. The reset comparator features built-in glitch immunity, making it impervious to fast transient on VCC. Twenty-four reset threshold voltage options are available, in increments between 2.2 V and 4.63 V, making these devices suitable for monitoring a variety of supplies.



The ADM6326, ADM6328, ADM6346 and ADM6348 are available in a space saving 3-lead SOT-23 package and operate over the extended temperature range of −40°C to +85°C.



As part of a complete signal chain the ADM6326, ADM6328, ADM6346 and ADM6348 supervisory circuits are compatible with ADI’s ADP2503 and ADP2504 dc-to-dc converters , ADP2121 switching regulator, and the ADP121 LDO.