Microchip MCP121T-315E/TT Micropower Voltage Supervisor SOT-23B

The Microchip MCP121T-315E/TT is a micropower voltage supervisor designed to ensure the reliable start-up and operation of microcontroller-based systems. It functions by holding a microcontroller in a reset state until the system supply voltage has reached and stabilised at a safe, predetermined level. This prevents erratic behaviour or data corruption during power-up and power-down sequences.

Featuring an active-low, open-drain reset output, the device offers flexible interfacing with a wide range of microcontrollers and logic circuits. A key benefit is its exceptionally low 1.75µA steady-state supply current, making it an ideal choice for power-sensitive applications such as portable, battery-powered devices where maximising battery life is critical.

The supervisor incorporates a fixed 120ms reset delay time after the supply voltage crosses the threshold, allowing for system stabilisation before releasing the microcontroller from reset. It operates over a wide supply voltage range from 1V to 5.5V, with a precise reset threshold voltage of 3.08V. The device is offered in a compact, industry-standard SOT-23B surface-mount package, enabling high-density PCB designs.

Applications

• Computers and computer peripherals
• Sensing and instrumentation equipment
• Portable and battery-operated devices

By integrating this robust voltage supervisor, designers can significantly enhance system reliability, prevent unpredictable operation during transient power conditions, and protect critical firmware and data.