LT1991CDD#PBF Application Field and Working Principle

Linear - Amplifiers - Instrumentation, OP Amps, Buffer Amps

The LT1991CDD#PBF is a fast, low power, low noise, high speed amplifier used in instrumentation and potentiometric circuit configurations. As an instrumentation amplifier, the LT1991CDD#PBF offers low noise and low offset performance with a wide input range and distortion performance.

Applications

The LT1991CDD#PBF can be used in high input impedance circuits such as: strain gauges, Photoresistors, and bridge circuitry. It can also be used as a gain sharing amplifier including strain gauge bridges, RTD measurements, or feedback amplifiers with piezo transducers.

Working Principle

The LT1991CDD#PBF is a differential design consisting of two wide-band, low-noise differential amplifiers. A differential architecture ensures immunity to common-mode noise as well as high common-mode rejection ratio (CMR). The output voltage of the LT1991CDD#PBF is essentially proportional to the difference between the two input terminals.

The amplifier works by implementing differential amplifiers, which are high gain amplifiers, operating at on the two input terminals. During operation, the two differential amplifiers store the differential signal at their outputs. Signals from either input terminals, which remain the same, cancel each other out at the output. Due to its inherent design, the LT1991CDD#PBF is able to reject both common-mode and differential-mode signals from either input terminal.

The LT1991CDD#PBF is also equipped with overload protection to prevent overload on either output terminal. The overload protection circuitry works by reducing the output voltage limit to zero volts if the input signal or common mode signal exceed the pre-set limits. This feature helps the LT1991CDD#PBF withstand the high input currents often experienced in instrumentation applications.

The LT1991CDD#PBF also features a high power supply rejection ratio (PSRR) to minimize interference from supply noise and power supply fluctuations. This feature helps to minimize noise and distortion in low voltage signals, enabling better signal integrity in instrumentation circuits.

Conclusion

In conclusion, the LT1991CDD#PBF is a high-performance, low-noise, low-voltage instrumentation amplifier. The amplifier offers excellent performance in low power, low noise, high speed operations. It has a wide input range and distortion performance at a low rate of power. It also provides high CMR, PSRR, and overload protection for improved signal integrity.