TL071CD Application Field and Working Principle

The TL071CD is a single channel low-noise high-gain operational amplifier IC (Integrated Circuit) designed for general-purpose use in instrumentation and audio systems. It is a members of the JFET input series, which means high-input impedance, low-noise, and feature-rich performance. The TL071CD is able to provide flat frequency responses, very low distortion, and extreme low-level signal capability. This makes it an ideal solution for many applications, including linear amplification, signal processing and conditioning, buffering, and other use-cases.

The TL071CD achieves high-gain performance by integrating several JFET-input amplifiers sharing a single output stage. The combination of a high input impedance, low-noise output, and dynamic range of 91dB (1kHz sample rate) makes it ideal for applications as an instrumentation amplifier or filter, where dynamic range and noise performance are important. With the use of the built-in compensation capacitors and resistors, the TL071CD is able to achieve a gain-bandwidth product of 1MHz at a unity gain of 0dB.

Linear Amplification

The TL071CD is well suited for linear amplification, as it is capable of operating on single-supply rail voltages of up to 15VDC and has low input bias and offset currents. The gain can be adjusted directly with external resistors, and the gain stability is maintained over a wide temperature range. The wide selection of output drive and voltage capabilities mean that the TL071CD is typically the go-to choice for most general-purpose linear amplification.

Signal Processing and Conditioning

The TL071CD is also used for signal processing and conditioning applications, such as increasing signal amplitude, phase correction, and signal filtering. With its unity-gain bandwidth at 1MHz, the TL071CD is capable of dealing with extremely fast signals, and the wide dynamic range of 91dB makes it suitable for tasks requiring low-noise accuracy such as AUX switches and other dynamic signal processing.

Buffering

The TL071CD is also used in buffering applications, providing a high open-loop gain. This buffers the input signal from the preceding stage, and provides a low-impedance output which can drive the next stage. The TL071CD has a high slew rate of 0.3V/us and fast settling time, allowing it to effectively act as a buffer between two stages in an amplifier design.

Working Principle

The most basic circuit of the TL071CD is the non-inverting amplifier configuration (Figure 1). This circuit consists of the TL071CD along with an external supply voltage, resistors R1 and R2, and an external signal to be amplified. The TL071CD functions as a voltage amplifier and its gain is determined by the ratio of the resistors R1 and R2.

Figure 1: Common non-inverting amplifier circuit of the TL071CD

The signal to be amplified is connected to the non-inverting input of the TL071CD, and is amplified by the combination of the resistor R1 and the PNP transistor connected to the non-inverting terminal. The PNP transistor acts as an impedance multiplier and modulates the gain of the amplifier. The output of the amplifier is connected to the inverting input of the TL071CD, which is held at virtual ground due to the negative feedback. The amplified signal is finally output at the output pin of the TL071CD.

The TL071CD is a very versatile operational amplifier circuit capable of a wide range of applications, from linear amplification to signal buffering. Its features make it an ideal solution for a variety of projects, with the ability to provide low-noise and low-distortion performance with almost any type of signal.