| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a transimpedance type preamplifier capable of adjusting frequency band with no change in transimpedance value nor load resistance value required. <P>SOLUTION: A preamplifier includes an amplifier part and a transimpedance part for feeding an output signal of the amplifier part back. Here, voltage generation means 13 of a power supply voltage (Vcc') supplied to a load resistance R0 of an input part (first stage) is provided in the same integrated circuit 10 as the preamplifier, and the voltage generation means can adjust a power supply voltage of the input part. The voltage generation means 13 consists of a serial circuit of resistors (R3-Rn) and a constant current source 16 connected to a reference voltage source (Vcc), capable of adjusting a resistance value of the resistors. For adjustment of a resistance value of the resistors, a plurality of connection taps (15a-15n) are led out of the resistors, and a connection tap is selected and connected with a wire 14. <P>COPYRIGHT: (C)2012,JPO&INPIT |
