| 摘要 |
PURPOSE:To simplify adjustment by a method wherein a gate potential of a FET is adjusted by electrically cutting the connection of unselected, unnecessary resistances to an externally lead-out terminal by using trim fuses. CONSTITUTION:In a gate potential setting circuit 16, the resistance values of a first gate potential adjusting resistor R0 and second gate potential adjusting resistors R1, R2,...R7 are determined so as to successively differ stepwise. Namely, a voltage supplied to a terminal VG, i.e., a gate potential, is a divided voltage of a power source voltage VDD by the resistor R0 and a resistor obtained by connecting one or more parallel-connected resistors selected out of the resistors R1, R2,...R7 to a load RC. By accordingly variably selecting the combination of the parallel-connected 7 second gate potential adjusting resistors, the gate potential VG is continuously varied. The second gate potential adjusting resistors are connected to trim fuses in series. When a required gate voltage is found, the value VG is varied while the quantity of light from a light emitting element is measured by applying a probe to an external terminal pad. In this manner, the bonding process after adjustment can be eliminated, the number of processes can be reduced, and facilities can be simplified. |
