TLC27L9CD

TLC27L9CD application field and working principle

TLC27L9CD is a Basic-specific JFET-input operational amplifier from Texas Instruments from the linear - amplifiers - instrumentation, OP amps, buffer amps category. The performance of the TLC27L9CD is tailored for low supply voltage application and is optimized for lower power consumption, making it ideal for portable battery power-operated applications. It is designed to provide high common-mode input voltage range and rail-to-rail output swing in all supply voltages ranging from 2.7 V to 18 V.

When using a low supply voltage, the TLC27L9CD can ‘t drive into the supply rails, so the output swing is limited to within the supply voltage. The common-mode input voltage range of the TLC27L9CD extends to -VSOS, allowing for a single-supply input range. With low supply voltages, the JFET-input amplifiers operate better than typical CMOS amplifiers that use more current and have limited linearity performance.

The TLC27L9CD is available in PDIP, SOIC, and TSSOP packages, and uses only a minimum amount of supply current (typically 400 µA), and the quiescent current only increases with larger signal swings. The TLC27L9CD has an input resistance of 3.5 MΩ and an open-loop gain of up to 120 dB at 20 kHz. The input voltage noise is exceptionally low at 0.9 µVrms and a typical output noise of 80 µVrms.

When it comes to applications, the TLC27L9CD is ideal for battery-operated applications, general-purpose low-noise applications, transducer amplifiers, active filters, and sample-and-hold circuits. This is due to the low supply voltage and low quiescent current capability of the device, allowing for a higher level of battery life and reduced power requirements.

Working Principle

The TLC27L9CD is a well-suited amplifier for low-noise applications because of its high open-loop gain, wide bandwidth, and extremely low input voltage noise. The TLC27L9CD offers high common-mode rejection and low distortion. It is also designed with a well-matched pair of complementary FETs on the input stage. In addition, the TLC27L9CD is designed with a wide temperature range and tight line and load regulation.

The working principle of the TLC27L9CD is based on the common source JFET topology, where a pair of complementary field-effect transistors (FETs) is used on the input stage. An input signal applied to the inverting input is amplified through the common-source amplifier stage, and the output is produced at the output stage.

The working principle of the TLC27L9CD can be further explained as an amplifier which combines an advanced bi-FET input stage with a low offset voltage. The bi-FET input stage is designed to provide high common-mode rejection and low noise levels, while the low offset voltage means that the unwanted DC voltage at the output is significantly reduced.

The compatible biasing for the TLC27L9CD is provided by an internal electronic-grade resistor. The resistor’s temperature coefficient ensures that the bias remains stable over temperature and provides stable offset voltage. Finally, the TLC27L9CD has an active output stage that is designed to provide rail-to-rail output swing and low output impedance.

Conclusion

The TLC27L9CD is an ideal choice for low-noise and battery-operated applications. It offers high common-mode input voltage range and rail-to-rail output swing in all supply voltages, is designed with a low-noise bi-FET input stage and incorporates an active output stage with low output impedance. In addition, the device has excellent characteristics in the areas of thermal tracking, line regulation, and load regulation, and the circuit can be designed with minimal external components.