Hi team,
The customer found that the AC voltage sampling of LM2904B was inaccurate when the circuit was lightly loaded, and reducing the output pull-down resistor of the AC voltage sampling op amp could be an improvement solution. In order to conduct a more accurate assessment, the project team has the following five questions that need to be consulted by the TI original manufacturer:
1. When selecting the resistance of the pull-down resistor of the AC voltage sampling operational amplifier LM2904BQDGKRQ1, in addition to considering the output capability of the operational amplifier, what other factors need to be considered?
2. What is the recommended resistance range for the output pull-down resistor?
3. If the output pull-down resistor value is 1kΩ, what adverse effects will there be?
4. How does the output pull-down resistor value being too large or too small affect the operating performance of the op amp?
5. Reducing the op amp output pull-down resistor can reduce the size of the op amp output glitches. What is the principle behind this? If it is due to the principle of voltage division, the amplitude of the fundamental wave of the output will theoretically be reduced, but from the above waveform we can see that the amplitude of the fundamental wave of the op amp has not actually changed.
Thanks！
