Microchip TCM809JENB713 Voltage Monitor: Features and Application Circuit Design
In modern electronic systems, ensuring stable and reliable operation is paramount, especially when dealing with microcontrollers and processors that are sensitive to power supply fluctuations. The Microchip TCM809JENB713 is a dedicated voltage monitor, or microprocessor supervisory circuit, designed to provide a robust solution for system reset control. This device is engineered to monitor a system's power supply voltage and assert a reset signal whenever the voltage drops below a predefined threshold, thereby preventing erratic operation during power-up, power-down, or brown-out conditions.
Key Features of the TCM809JENB713
The TCM809JENB713 stands out due to its integration of critical supervisory functions into a compact, 3-pin SOT-23 package. Its primary features include:
Precision Voltage Monitoring: The device is factory-trimmed to monitor a fixed voltage threshold of 4.63V. This high level of accuracy ensures the microcontroller is held in reset until the VCC supply is stable and within the correct operating range.
Active-Low Reset Output: It provides an active-low reset signal (/RESET), which is the standard logic level used to initiate a reset sequence in most microcontrollers. This output remains asserted as long as VCC is below the threshold and for a minimum period after it rises above, guaranteeing a proper reset pulse.
Ultra-Low Supply Current: With a very low typical supply current of only 9µA, the TCM809JENB713 is an excellent choice for power-sensitive and battery-operated applications, minimizing its impact on overall system power consumption.
High Noise Immunity: Internal circuitry provides a high degree of noise immunity on the VCC pin, making the device highly reliable in electrically noisy environments, which is common in industrial and automotive applications.
Small Form Factor: The SOT-23 package is ideal for space-constrained PCB designs, allowing for placement very close to the microcontroller's reset pin to minimize noise pickup.
Application Circuit Design
Implementing the TCM809JENB713 in a circuit is remarkably straightforward, requiring only a single external component for basic functionality. The typical application circuit is shown below.
[Simple Circuit Diagram]
```
VCC (3.0V to 5.5V)
|
+-------+---[100nF]--- GND
| |
| TCM809JENB713
| |
| | /RESET
| +-------/-----> To MCU Reset Pin
|
MCU VCC
```
Design Procedure and Considerations:
1. Power Supply Connection (VCC): Connect the VCC pin of the TCM809JENB713 directly to the same power supply rail as the microcontroller it is monitoring. This is the rail that will be supervised.
2. Decoupling Capacitor: A 100nF ceramic decoupling capacitor should be placed as close as possible between the VCC pin and Ground (GND). This capacitor is crucial for stabilizing the supply voltage at the monitor's input and filtering out high-frequency noise, ensuring accurate voltage monitoring.
3. Reset Output Connection: The active-low reset output (/RESET) is connected directly to the reset pin of the microcontroller. This pin is typically an active-low input on the MCU. No external pull-up resistor is required as the output is push-pull, simplifying the design.
4. Ground Connection: Connect the GND pin to a clean, stable system ground plane.
This simple design ensures that the microcontroller is held in a safe reset state during power-up until VCC stabilizes above 4.63V. The /RESET signal will also immediately assert if the supply voltage sags below this threshold during operation, triggering a controlled system reset.
ICGOOODFIND: The Microchip TCM809JENB713 is an exceptionally efficient and reliable solution for ensuring system integrity in 5V-based designs. Its combination of precision monitoring, ultra-low power consumption, and extreme simplicity makes it an indispensable component for anyone designing robust embedded systems, from consumer electronics to industrial control.
Keywords: Voltage Monitor, Microprocessor Supervisory Circuit, Reset Circuit, Brown-Out Protection, Low-Power Design.
