Power-Supply Monitor with Reset

The MAX700/MAX701/MAX702 are supervisory circuits used to monitor the power supplies in microprocessor (µP) and digital systems. The active-low RESET/RESET outputs of the MAX700/MAX701/MAX702 are guaranteed to be in the correct state for VCC voltages down to +1V (Figure 4). They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V-powered circuits.

The MAX702 is the simplest part in the family. When VCC falls to 4.65V, active-low RESET goes low. The MAX702 also provides a debounced manual reset input. The MAX701 performs the same functions but has both active-low RESET and RESET outputs. Their primary function is to provide a system reset. Accordingly, an active reset signal is supplied for low supply voltages and for at least 200ms after the supply voltage reaches its operating value.

In addition to the features of the MAX701 and MAX702, the MAX700 provides preset or adjustable voltage detection so thresholds other than 4.65V can be selected, and adjustable hysteresis. All parts are supplied in 8-pin PDIP and Narrow SO packages in commercial and extended temperature ranges.

Applications

* Computers * Controllers * Critical µP Power Monitoring * Intelligent Instruments

* Min 200ms Active-Low RESET Pulse on Power-Up, Power-Down, and During Low-Voltage Conditions

* Reset Threshold Factory Trimmed for +5V Systems

* No External Components or Adjustments with +5V-Powered Circuits

* Debounced Manual Reset Input

* Preset or Adjustable Voltage Detection (MAX700)

* Adjustable Hysteresis (MAX700)

* 8-Pin PDIP and Narrow SO Packages