| 摘要 |
PROBLEM TO BE SOLVED: To provide a track/hold(T/H) amplifier capable of high-speed stable operation. SOLUTION: Concerning the T/H amplifier composed of a main T/H amplifier 31a for amplifying an analog signal and a replica control circuit 34a, the main T/H amplifier is composed of an MOS switch 24, capacitors C1 and C2, MOS differential pair M1 and M2 biased by a first voltage control current source 21, cascade transistors M3 and M4 for returning the output of this differential pair, load resistors R1 and R2 for output voltage generation and a second voltage control current source 26 for biasing the cascade transistors. The replica control circuit has the replica amplifier of the same circuit configuration as the main T/H amplifier and a feedback circuit composed of a resistor and an operational amplifier and supplies the operating point of a common mode, control voltage Vcmn and Vgain of gain to the main T/H amplifier. Thus, the stable T/H amplifier capable of independently controlling the gain and operating point can be provided.
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