| 摘要 |
PROBLEM TO BE SOLVED: To achieve high sensitivity and a wide input dynamic range, instantaneous response corresponding to burst data, and gain switching stability. SOLUTION: A gain switching judgment circuit 250 outputs a gain switching signal SEL based on the comparison result of a comparison input voltage Vc, i.e. a differential output signal from an intermediate stage buffer circuit 230, and first hysteresis characteristics, and performs operation for switching gains of first and second transimpedance amplifier core circuits 210 and 220. Based on the comparison result of the comparison input voltage Vc and second hysteresis characteristics of a voltage detection level lower than that of the first hysteresis characteristic, gain switching operation is stopped and the gains of the first and second transimpedance amplifier core circuits are fixed. COPYRIGHT: (C)2007,JPO&INPIT
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