Microchip MCP100-450DI/TO Voltage Supervisor: Features and Application Circuits
In the realm of electronic design, ensuring system stability and reliability is paramount. The Microchip MCP100-450DI/TO is a robust voltage supervisor (or microprocessor reset IC) specifically engineered to monitor power supply voltages and provide a reset signal to microcontrollers, DSPs, or FPGAs during critical events like power-up, power-down, or brown-out conditions. Housed in a rugged TO-92 package, this device is well-suited for industrial, automotive, and consumer applications where precise voltage monitoring is essential.
Key Features of the MCP100-450DI/TO
The MCP100 series offers several critical advantages for system designers. The MCP100-450DI/TO variant is set to monitor a 4.50V threshold, making it ideal for supervising 5V and 3.3V power supplies commonly found in digital systems. Its standout features include an active-low, open-drain reset output, which allows for easy interfacing with various logic families and enables wired-AND configurations in complex systems. The device requires extremely low supply current, typically 9 µA, making it perfect for battery-powered and low-energy applications. Furthermore, it is designed to operate over a wide temperature range (-40°C to +125°C), ensuring performance in harsh environments. The built-in hysteresis prevents reset signal oscillation near the trip point, guaranteeing a stable and clean reset pulse.
Typical Application Circuits
The primary function of the MCP100 is to keep a microprocessor in a known safe state until the power supply is stable. Here are two common application circuits:
1. Basic Microcontroller Reset Circuit:
The most straightforward application is connecting the MCP100 directly between the power supply (Vcc) and the reset pin of a microcontroller (µC). The Vdd pin is connected to the system's 5V rail. The active-low reset output (/RESET) is tied to the µC's active-low reset input. A pull-up resistor (typically 10kΩ) is required on the /RESET line to Vcc since the output is open-drain. When Vcc drops below 4.50V, the /RESET output is driven low, holding the µC in reset. Once Vcc rises above the threshold and remains stable for the built-in timeout period (typically 350 ms), the /RESET line is released, allowing the µC to begin normal operation.
2. Manual Reset Extension:
For systems requiring a user-initiated reset, the open-drain output allows for easy implementation. A manual reset switch can be added by connecting a momentary switch between the /RESET node and ground. Pressing the switch pulls the reset line low, regardless of the supervisor's state, providing a reliable way to trigger a system reset on demand. This circuit is invaluable for debugging and user control.
Design Considerations
When implementing the MCP100, certain factors must be considered. The choice of the pull-up resistor value is a trade-off between power consumption and rise time; 10kΩ is a standard value. For noisy environments, a small decoupling capacitor (0.1µF) placed close to the device's Vdd pin is highly recommended to ensure accurate monitoring. Designers must also ensure that the selected variant's threshold voltage (Vtrip) matches the requirements of the host processor's power supply and its minimum operating voltage.
The Microchip MCP100-450DI/TO is an exceptionally reliable and simple solution for safeguarding microprocessors against unstable power conditions. Its low power consumption, wide operating temperature range, and open-drain output make it a versatile choice for a vast array of applications, from automotive electronics to industrial control systems. By providing a guaranteed valid reset signal, it significantly enhances the robustness and reliability of any embedded design.
Keywords: Voltage Supervisor, Microprocessor Reset IC, Open-Drain Output, Brown-Out Protection, Power Management.
