| 摘要 |
PURPOSE:To reduce the settling time by selecting a value of a phase compensation capacitor in response to a hold capacitor so as to obtain an optimum transient response characteristic. CONSTITUTION:An input signal 6 is given to a noninverting input of an operational amplifier 1 and its output is given to a hold capacitor 4 and a buffer circuit 3 via a switch circuit 2 switched by a sample pulse 7 and the other terminal of the hold capacitor 6 is connected to ground and the output of the buffer circuit 3 is given to an inverting input of the operational amplifier 1 to constitute a feedback loop and the signal is fed back to an internal circuit of the operational amplifier 1 via the phase compensation capacitor 5. Through the constitution above, the switch 2 and the hold capacitor 4 form a low pass filter having a frequency characteristic different depending on the ON-resistance of the switch 2 and the value of the hold capacitor 4. Thus, in selecting the phase compensation capacitor 5 properly, the optimum transient response is obtained and the settling time is reduced.
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