| 摘要 |
PURPOSE:To reduce the needless radiation of high frequency from the output terminal of a semiconductor integrated circuit by forming a low-pass filter, making use of a bonding wire. CONSTITUTION:A air-core coil 5 is formed by deforming a bonding wire which connects the output pad 3 of the chip inside an integration circuit with the lead frame 6, and it is used as the coil of the input part of a filter. Moreover, the lead frame 6 is sandwiched from above and below by packages including ferrite to form a coil, and this is used as the coil at the output part of the filter. Furthermore, a transistor for capacitive coupling is formed inside the chip, and this is used as a capacitor, making use of the gate capacitance. That is, a capacitor is provided between the lead frame 6 and an earth by connecting the pad for capacitive coupling with the lead frame 6 by a bonding wire 4. Accordingly, a T type of constant K-type low-pass filter is made by two coils and the capacitors. Needless radiation can be reduced by the addition of a minimum of elements. |
