JPH026669Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a SIP type surface acoustic wave device.

Traditionally SIP (Single Inline Package)
Surface acoustic wave devices are used as filters in electronic equipment. This surface acoustic wave device has a structure as shown in the front view of FIG. 1 and the cross-sectional view of FIG. 2. To briefly explain this,
A chip 5 is mounted on a base 6, in which an input transducer 3 and an output transducer 4 are formed by combining a multi-strip coupler 2 consisting of a plurality of electrodes and a pair of comb-shaped electrodes on a piezoelectric substrate 1. It is attached to a supported metal tray 7 using a conductive adhesive 8, and the pads 9 to 12 of the input/output transducers 3 and 4 and the terminals 13 to 16 are connected using bonding wires 17 to 20. After that, cover the resin case 21 and attach the base 6 with adhesive.
It is sealed in. Due to the structure of such a surface acoustic wave device, one electrode 3a of the input transducer 3 to which the hot signal 22 is applied and its pad 9 are usually placed close to the side surface of the chip 5. If the electrode 3a and the pad 9 on the side to which the hot signal 22 is applied are close to the side surface of the chip 5, the substances contained in the conductive adhesive 8 that adhered the chip will be ionized and moved by moisture etc. However, there may be a problem that the electrode 3a and pad 9 are corroded. The present invention was devised to improve this drawback.

Therefore, in the present invention, a chip 5 is provided, in which input and output transducers 3 and 4 each having a combination of at least one pair of comb-shaped electrodes are formed on a piezoelectric substrate 1; A base 6 is provided with input/output terminals 13 to 16 and a metal tray 7 for chip mounting, and a SIP type resin case 21, and the chip 5 is mounted on the tray 7 with conductive adhesive. At the same time, the chip 5 is housed in the case 21 by sealing the case 21 and the base 6, and the transducers 3 and 4 are fixed in the case 21. Pads leading out from each electrode and the terminal 1
3 to 16 are surface acoustic wave devices connected by bonding wires 17 to 20, respectively, and the pads of the transducers 3 and 4 are connected to the side to which the hot signal 22 of the input transducer 3 is applied. The electrode 3c and the pad 23 leading out from it are located at the center of the substrate 1, and the pad 10 leading out from the ground side electrode 3b of the input transducer 3 and each electrode of the output transducer 4 The pads 11 and 12 which are led out are formed so as to be located at the same peripheral portion of the substrate 1 facing the terminals 13 to 16.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

A first embodiment is shown in FIG. 3, and a second embodiment is shown in FIG. In the figures, parts that are the same as those of the conventional product shown in FIG. 1 are designated with the same reference numerals.

In the first embodiment shown in FIG. 3, the ground electrode 3b of the input transducer 3 is
is placed closer to the side surface of the substrate 1, and the electrode 3c to which the other hot signal 22 is applied and its pad 23 are placed in the center of the substrate 1.The other configuration is shown in FIG. It is the same as the conventional product.

In this embodiment configured as described above, the electrode 3c to which the hot signal is applied and the pad 23 are located in the center of the chip 5 and are separated from the periphery, so that they are not affected by the ions of the adhesive 8. Therefore, the fear of disconnection is eliminated.

Next, in the second embodiment shown in FIG. 4, the ground side electrode 3b of the input transducer 3 is arranged closer to the side surface of the substrate 1, and the electrode 3c and pad 23 on the side to which the hot signal 22 is applied are arranged. The arrangement in the center of the board 1 is the same as in the previous embodiment, but the lead wire 24 from the ground electrode 3b to the pad 10 is passed through the multi-strip coupler 2 side.
4 and the bonding wire 17 are eliminated. (In the previous embodiment, the lead wire 24 and the bonding wire 17 intersect with each other.) Note that the effect is exactly the same as in the previous embodiment.

As explained above, the surface acoustic wave device of the present invention is constructed by arranging the electrode of the input transducer on the side to which the hot signal is applied and its pad in the center of the substrate, and using adhesive to bond the chip to the metal tray. This eliminates corrosion and prevents problems such as wire breakage.

[Brief explanation of drawings]

Fig. 1 is a front view of a conventional SIP type surface acoustic wave device, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a front view of a surface acoustic wave device according to the first embodiment of the present invention. 4 are front views of the second embodiment. DESCRIPTION OF SYMBOLS 1... Piezoelectric substrate, 2... Multi-strip coupler, 3... Input transducer, 4... Output transducer, 5... Chip, 7... Metal tray, 8... Adhesive, 9 ~12...Patsudo, 13
~16...terminal, 17-20...bonding wire, 21...resin case.

Claims (1)

[Claims for Utility Model Registration] Input and output transducers 3 and 4 in which at least one pair of comb-shaped electrodes are combined on a piezoelectric substrate 1
a base 6 to which the input/output terminals 13 to 16 of each of the transducers 3 and 4 and a metal tray 7 for mounting the chip are attached, and a SIP type resin case. 21, the chip 5 is adhesively fixed on the tray 7 with a conductive adhesive 8, and the chip 5 is housed in the case 21 by sealing the case 21 and the base 6. and the pads leading out from each electrode of the transducers 3 and 4 and the terminal 1 within the case 21.
3 to 16 are surface acoustic wave devices connected by bonding wires 17 to 20, respectively, and the pads of the transducers 3 and 4 are
Hot signal 2 of the input transducer 3
The electrode 3c on the side to which 2 is applied and the pad 23 led out from it are located in the center of the substrate 1, and the pad 10 led out from the ground side electrode 3b of the input transducer 3 and the output transformer A surface acoustic wave device characterized in that pads 11 and 12 led out from each electrode of the gauger 4 are formed so as to be located at the same peripheral portion of the substrate 1 facing the terminals 13 to 16.