Operational Amplifier Selection

Jul 14, 2025#电路7

AI Translation

This post is translated from Chinese into English through AI.View Original

AI-generated summary

The document discusses the selection of operational amplifiers (op-amps) for a design project using the OP07. The goal is to amplify a 1V peak-to-peak sine wave at frequencies between 100K and 1M by a factor of 2. However, testing revealed that at 100K, the output waveform resembled a triangle wave, indicating distortion. The OP07's gain bandwidth product is 0.5MHz, which should theoretically support 2x gain at 100K, but its slew rate of 0.3V/µs is insufficient for the required 6.28V/µs. In contrast, the AD8051, powered by ±5V, has a minimum slew rate of 105V/µs, making it suitable for the design requirements.

When designing a single-channel operational amplifier with the OP07, the design goal is to amplify a 1V peak-to-peak sine wave from 100K to 1M by 2 times. However, during testing, it was found that the output waveform at 100K frequency resembled a triangular wave. The datasheet states that the gain bandwidth product of the OP07 is 0.5MHz, which normally should not be an issue for a 2x gain at 100K frequency.

However, the datasheet also states that the slew rate of the OP07 is 0.3V/us. Based on the design goal, it can be calculated that the operational amplifier's slew rate needs to reach at least 6.28V/us. It can be seen that the OP07's slew rate is completely insufficient, leading to waveform distortion.

When powered with ±5V, the minimum slew rate of the AD8051 is 105V/us, thus meeting the design requirements.