Low-Cost, µP Supervisory Circuits
Low-Cost Reset + Watchdog ICs
The MAX705–MAX708/MAX813L microprocessor (µP) supervisory circuits reduce the complexity and number of components required to monitor power-supply and battery functions in µP systems. These devices significantly improve system reliability and accuracy compared to separate ICs or discrete components.
The MAX705/MAX706/MAX813L provide four functions:
- A reset output during power-up, power-down, and brownout conditions.
- An independent watchdog output that goes low if the watchdog input has not been toggled within 1.6 seconds.
- A 1.25V threshold detector for power-fail warning, low-battery detection, or for monitoring a power supply other than +5V.
- An active-low manual-reset input.
The MAX707/MAX708 are the same as the MAX705/MAX706, except an active-high reset is substituted for the watchdog timer. The MAX813L is the same as the MAX705, except RESET is provided instead of active-low RESET.
Two supply-voltage monitor levels are available: The MAX705/MAX707/MAX813L generate a reset pulse when the supply voltage drops below 4.65V, while the MAX706/MAX708 generate a reset pulse below 4.40V. All four parts are available in 8-pin DIP, SO and µMAX® packages.
- Supervisory-Function Integration Significantly Improves System Reliability While Reducing Board Space
- µMAX Package
- Guaranteed Active Low RESET Valid at VCC = 1V
- 200ms Reset Pulse Width
- Debounced TTL/CMOS-Compatible Manual-Reset Input
- Active-High Reset Output (MAX707/MAX708/MAX813L)
- Precision-Supply Voltage Monitor
- 4.65V (MAX705/MAX707/MAX813L)
- 4.40V (MAX706/MAX708)
- Voltage Monitor for Power-Fail or Low-Battery Warning
- Critical µP Power Monitoring
- Intelligent Instruments
|Part Number||Reset Thresh.|
|Reset Out||tRESET||Watchdog Feature||Watchdog Timeout||Supervisor Features||Reset Thresh. Accur.|
|min||@ +25°C||max||See Notes|
|MAX705||3.3 to 5.5|
|85ms to 300ms|
|1s to 2s|
|1s to 2s|
|Device||Fab Process||Technology||Sample size||Rejects||FIT at 25°C||FIT at 55°C||Material Composition|