Question

In a sample and hold circuit with two buffers, one at input and the other at output, the primary requirement for both buffers is:

• A. Input buffer: high slew rate; output buffer: low bias current
• B. Input buffer: low bias current; output buffer: high slew rate
• C. Both should have low bias currents
• D. Both should have high slew rate

Hint:

High slew rate in both buffers is essential to maintain signal accuracy in sample and hold circuits.

Answer 1

The Correct Option is D

The primary requirement in a sample and hold circuit with two buffers is that both buffers should exhibit high slew rates. This requirement is crucial due to the following reasons:

1. Slew Rate: The slew rate is a critical parameter as it defines how fast the output can follow changes in the input signal. In a sample and hold circuit, quick response times are essential to accurately capture the input signal during the sampling phase and maintain the output during the holding phase.
2. High Slew Rate for Input Buffer: The input buffer must quickly respond to rapid changes in the input signal to ensure accurate sampling. A high slew rate minimizes the delay in charging the sampling capacitor, allowing it to track the input voltage precisely.
3. High Slew Rate for Output Buffer: The output buffer must maintain and stabilize the held voltage throughout the hold period. A high slew rate is essential to avoid distortion and ensure the output signal rapidly adapts to changes as required during the sample and hold transitions.
4. Conclusion: Both buffers require high slew rates to efficiently perform their roles in a sample and hold circuit, ensuring accurate sampling and minimal signal distortion.