Microchip MCP619T-I/SL CMOS Op-Amp: Features and Application Circuits

The Microchip MCP619T-I/SL is a precision CMOS operational amplifier that combines low power consumption with rail-to-rail input and output operation, making it an excellent choice for a wide range of portable and battery-powered applications. Available in a compact SOIC-8 package, this op-amp is part of the MCP619 family, which is designed to offer a balance of performance and power efficiency.

Key Features

One of the most significant advantages of the MCP619 is its extremely low quiescent current, typically drawing only 19 µA per amplifier. This makes it ideal for applications where power conservation is critical, such as in handheld instruments, remote sensors, and Internet of Things (IoT) nodes. Despite its low power draw, it maintains a respectable gain bandwidth product of 50 kHz and a low typical offset voltage of 150 µV.

The op-amp's rail-to-rail input and output capability allows the signals to swing very close to both power supply rails. This maximizes the dynamic range in low-voltage systems, which is crucial when operating from a single supply voltage as low as 2.3V up to 5.5V. Furthermore, it exhibits stable operation with high capacitive loads, simplifying design in circuits where this is a concern.

Application Circuits

The versatile characteristics of the MCP619T-I/SL enable its use in numerous fundamental circuit configurations.

1. Photodiode Transimpedance Amplifier (TIA): A classic application for a low-input-bias-current CMOS op-amp is converting the small current from a photodiode or other sensor into a measurable voltage. The MCP619's low input bias current (1 pA typical) minimizes error in this current-to-voltage conversion. A feedback resistor (Rf) sets the gain (Vout = Ipd Rf), and a feedback capacitor (Cf) is often added for stability.

2. Active Low-Pass Filter: The amplifier's bandwidth is well-suited for building anti-aliasing filters or signal conditioning stages for low-frequency analog signals. A simple Sallen-Key filter topology can be implemented using the MCP619 to remove high-frequency noise before an analog-to-digital converter (ADC).

3. Portable Sensor Interface: For battery-powered sensor modules measuring temperature, pressure, or light, the MCP619 acts as an ideal signal conditioner. It can amplify a small sensor signal while its rail-to-rail output ensures the full ADC range is utilized. The entire circuit can be powered from a single 3V lithium cell, drawing minimal current to extend battery life for years.

4. Voltage Follower (Buffer): The high input impedance and low output impedance of the MCP619 make it perfect for buffering signals between a high-impedance source (like a sensor) and a load (like an ADC), preventing the source from being affected by the load.

ICGOODFIND Summary

The Microchip MCP619T-I/SL stands out as an exceptional low-power operational amplifier for space-constrained, battery-dependent designs. Its combination of rail-to-rail operation, micropower consumption, and CMOS input characteristics makes it a superior choice for sensor interfacing, signal conditioning, and active filtering in portable and industrial applications.

Keywords:

Low Power Consumption

Rail-to-Rail Input/Output

CMOS Operational Amplifier

Sensor Interface

Transimpedance Amplifier