This Application Note describes how to connect the STM809, STM810, STM811 and STM812 Reset Circuits to Microprocessor Systems.
This application note explains how to connect ST Reset Circuits, specifically the STM809, STM810, STM811, and STM812 devices, to microprocessor systems. It details the function of these low-power supervisory devices in monitoring power supplies and preventing system malfunctions caused by noise or glitches during power-up and normal operations.
The document provides specific guidance on connecting these circuits in various scenarios, including noisy environments, connections to bi-directional microprocessor reset inputs, and ensuring the reset output remains valid down to 0V. It includes recommended component values for external capacitors and resistors to ensure reliable operation.
| Reset Threshold (Typical) | 2.55V to 4.72V |
|---|---|
| Minimum MR Pulse Width | 10 μs |
| Recommended External Capacitor for Noise | 0.1 μF |
| Recommended Resistor for Bi-directional Reset | 4.7 kΩ |
| Recommended Resistor for VCC = 0V Validity | 100 kΩ |
The note covers the STM809, STM810, STM811, and STM812 Reset Circuits.
The recommended value of the capacitor is 0.1 μF.
The recommended value of the resistor is 4.7 kΩ.
When the MR input is driven Low, the Reset output becomes active after a delay and remains active for a time trec after the switch is released.