Microchip TCM809TENB713 System Reset Circuit Design and Application
In the realm of embedded systems and microcontroller-based applications, ensuring reliable and predictable operation is paramount. A critical factor in achieving this reliability is the system's ability to recover from power-related anomalies and software lock-ups. The system reset circuit forms the foundational bedrock of a robust embedded design, and dedicated microprocessor supervisory devices like the Microchip TCM809TENB713 are engineered specifically for this vital role. This article delves into the design and application of this particular component.
The Microchip TCM809TENB713 is a member of the TCM809/810 series of microcontroller supervisors. It is a 3-pin device that integrates a precise voltage monitor and a manual reset input. Its primary function is to monitor the VCC power supply of a microcontroller (or other digital systems). When the VCC voltage dips below a factory-set trip point (typically 2.63V for the 'T' variant), the device asserts an active-low reset signal (/RESET). This signal remains asserted until VCC rises above the trip point and remains stable for a minimum delay period, typically 140ms, ensuring the power supply and system oscillator have stabilized before the microcontroller begins execution.
Circuit design using the TCM809TENB713 is remarkably straightforward, a key feature that contributes to its widespread adoption. The typical application circuit requires only the IC itself and a single bypass capacitor across VCC and GND. The three pins are:
1. VCC: Connected directly to the microcontroller's power supply rail.
2. GND: Connected to the common ground.
3. /RESET: This open-drain output is connected directly to the microcontroller's active-low reset pin. An external pull-up resistor is not required as it is integrated within the device.
The inclusion of a manual reset input (MR), available on the TCM810 series but notably absent on this specific 3-pin TCM809 variant, is a key selection criteria. For designs where a physical reset button is unnecessary, the TCM809TENB713 offers a cost-effective and space-saving solution.
The applications for the TCM809TENB713 are extensive. It is indispensable in:
Power-On Reset (POR): Providing a controlled, predictable reset sequence during system startup.
Brown-Out Protection: Safeguarding against data corruption and erratic behavior during instances of power supply droop or partial failure.
Battery-Powered Equipment: Ensuring devices like meters, sensors, and portable instruments reset correctly as battery voltage decays.
Automotive and Industrial Electronics: Providing resilience against the noisy and fluctuating power environments typical in these fields.
The Microchip TCM809TENB713 is an exemplary solution for system reset management. Its simplicity, reliability, and minimal external component count make it an ideal choice for designers seeking to enhance the robustness of their microcontroller-based systems without complicating the design. It effectively eliminates uncertainty during power transitions, ensuring a known and safe starting state for the entire embedded system.
Keywords:
1. Microcontroller Supervisor
2. Power-On Reset (POR)
3. Brown-Out Detection
4. Voltage Monitoring
5. System Reliability
