| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a bias adjusting method with which electric characteristics of a circuit unit including a bias circuit comprising an adjustable impedance element and a trimmable resistor, for example, can be easily adjusted into desired characteristics. <P>SOLUTION: A circuit unit 13 is placed on a stage 12 and moved, and a trimming part of a non-illustrated trimmable resistor in the circuit unit is aligned with a laser irradiation head 11a. An external power source 14 is connected to a non-illustrated bias circuit of the circuit unit 13, a supply voltage is varied, characteristics of the circuit unit 13 are measured by a circuit characteristic measuring instrument 16, and a vias voltage Vg0 at a time when desired characteristics can be obtained, is measured by a voltage measuring instrument 15 and stored in a storage device 17. Next, the external power source 14 is detached from the bias circuit, power is supplied from a non-illustrated internal power source to the circuit unit 13 and while a bias voltage of the bias circuit is measured by the voltage measuring instrument 15, the trimming part of the trimmable resistor is irradiated with a laser, and trimming is performed until the bias voltage becomes Vg0. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
