KR20050075965A - Saw package - Google Patents

Abstract

The present invention is provided with a saw filter chip for generating a surface acoustic wave to filter a signal, a groove for mounting the saw filter chip, a saw filter head for mounting the saw filter chip in the groove, coupled to the saw filter head, Consists of the input and output terminals of the saw filter chip, and a connection pin electrically connected to the ground terminal. The feed throw generated by the IDT implementation of the package can be pulled out through the ground of the package to improve control of the feed throw.

Description

Saw package {SAW PACKAGE}

The present invention relates to a saw package that improves the controllability of a feed throw by preventing the acoustic waves generated from the saw filter chip from being reflected in the package space.

In general, surface acoustic waves represent a state of waves transmitted along the surface of the substrate and have a feature of rapidly attenuating in the depth direction. The SAW filter uses this feature as a frequency selective device.

That is, the SAW device temporarily forms a metal electrode on a highly insulative substrate and applies a piezoelectric twist to the substrate surface. This action causes a physical wave. Since the wave speed transmitting the SAW element surface is slower than the electromagnetic wave, it is used as a filter to temporarily delay an electric signal or pass only a specific frequency signal.

The SAW filter is a ceramic container that protects a semiconductor device or a function, and is formed in a package form that protects an internal circuit from a harmful environment and provides a means for dissipating heat generated therein and connecting it to the outside.

A surface acoustic wave device is a device used to convert an applied electric signal into a mechanical signal having a wave. These surface acoustic wave devices are attached to the ends of signal transmitting and receiving pipes of mobile communication devices such as mobile phones, which are increasingly used day by day, and extract SAW (Surface Acoustic Wave) for extracting necessary signals from the external transmitting and receiving signals to users. ) It is widely used as a filter.

The SAW filter combines a first resonator for processing and filtering a high frequency signal and a second resonator for processing and filtering a signal in a low frequency band so as to combine a double mode resonator coupled SAW filter (hereinafter, referred to as a DMS filter). Used as.

1 is a view showing the structure of a general saw filter.

Referring to FIG. 1, a structure of a saw filter chip 100 using surface acoustic waves is formed by depositing and etching a metal film on an insulating (piezoelectric) substrate 110 to form inductance and capacitance in the form of a strip line. The first resonator 120a and the second resonator 120b filter capable of filtering the same may be manufactured on the insulating substrate 110.

In this case, while etching the metal film deposited on the insulating substrate 110 to form a metal pattern of the IDT (Inter Digital Transducer) constituting the first resonator (120a).

Similarly, an IDT metal pattern constituting the second resonator 120b is formed on the insulating substrate 110.

In the saw filter chip 110 having the structure as described above, the surface acoustic wave generated by the first resonator 120a is transmitted to the second resonator 120b along the surface of the insulating substrate 110 to filter the signal. )

Since the velocity of the surface acoustic wave generated on the insulating substrate 110 is slower than that of the electromagnetic wave, the surface acoustic wave acts to delay the temporarily applied electric signal.

It is also used as a resonant filter that only passes certain frequency signals.

2A and 2B are views illustrating a structure of a saw package incorporating a conventional saw filter chip.

2A and 2B, the saw filter chip 220 is attached to an upper surface of the flat package header 210. In this case, the input / output terminal and the ground terminal of the saw filter chip 220 are wire bonded to the input / output terminal and the ground terminal of the package header 210, respectively.

An input pin 242 for applying an input signal to the saw filter chip 220, an output pin 246 for outputting an output signal, and a ground pin 244 for grounding the saw filter chip 220 may include the package. Each is coupled along the circumference of the header 210.

The input pin 242, output pin 246 and ground pins 244 are electrically contacted when the saw package 200 is coupled onto the PCB.

However, in the related art, feed through occurs, but the ground area is not large, so that the feed through appears at the output as it is, and thus a desired waveform cannot be obtained.

Accordingly, it is an object of the present invention to provide a saw package that improves control of feed throw by embedding the saw filter chip in the groove by making a groove corresponding to the size of the saw filter chip in the saw package.

According to an aspect of the present invention, a saw filter chip for generating a surface acoustic wave to filter a signal and a groove for mounting the saw filter chip are provided to install the saw filter chip in the groove. A saw package is provided comprising a filter head and a connection pin coupled to the saw filter head and electrically connected to an input / output terminal and a ground terminal of the saw filter chip.

When the saw filter chip is mounted on the saw filter head, a sound absorbing material is applied to an end of the saw filter chip, so that the reflected wave generated in the saw filter chip falls to the ground by the sound absorbing material.

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

3A and 3B are views illustrating a saw package structure incorporating a saw filter chip according to an exemplary embodiment of the present invention.

3A and 3B, a saw filter chip 320 is disposed on a power saving substrate, and the saw filter chip 320 is disposed to generate surface acoustic waves by applying an electrical signal to the IDT terminal. It is mounted inside the package 300.

At this time, the saw package 300 is etched by a size corresponding to the ground area for embedding the saw filter chip 320. The saw filter chip 320 is embedded in an etched position of the saw package head 310. Then, the area of the saw filter chip 320 grounded on the saw package head 310 is widened, thereby improving the control capability of the feed throw.

A plurality of connection pins are coupled to the saw package head 310. The connection pins include an input pin 342 for applying an electrical signal to the saw filter chip and an output pin output from the saw filter chip 320. 346 and a ground pin 344 for electrically grounding the saw filter chip 320.

Such connection pins are mounted on the PCB as one device to enable signal transmission with other electrical components.

In addition, the saw package 300 is the end of the saw filter chip 320 and the saw package head 310 is grounded to protect the saw filter chip 320 from moisture, heat, vibration applied from the outside The sound absorbing material 350 is apply | coated to this.

Reflected waves generated from the saw filter chip 320 are transmitted to the ground terminal 344 by the sound absorbing material 350 so that the reflected waves fall to the ground.

In the saw package 300 configured as described above, the first resonator of the saw filter chip 320 generates surface acoustic waves and transmits them to the second resonator.

In this case, surface acoustic waves generated by the first resonator are reflected on the surface of the second resonator, and the reflected waves are absorbed by the sound absorbing material 350.

Then, the sound absorbing material 350 allows the absorbed reflected wave to exit through the ground terminal 344.

That is, since the feed throw is pulled out through the ground 344 of the package 300, the control capability of the feed throw is improved.

The present invention is not limited to the above embodiments, and many variations are possible by those skilled in the art within the spirit of the present invention.

As described above, according to the present invention, the feed throw generated by the IDT implementation of the package can be provided through the ground of the package to provide a saw package that can improve the control capability of the feed throw.

1 is a view showing the structure of a typical saw filter.

2A and 2B are views showing the structure of a saw package incorporating a conventional saw filter chip.

3A and 3B illustrate a saw package structure incorporating a saw filter chip according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

300: saw package 310: saw package head

320: saw filter chip 350: suction material

342 input pin 344 ground pin

346 output pin

Claims (3)

A saw filter chip for generating a surface acoustic wave to filter the signal; A saw filter head having a groove for mounting the saw filter chip to mount the saw filter chip in the groove; A connection pin coupled to the saw filter head and electrically connected to an input / output terminal and a ground terminal of the saw filter chip. Saw package comprising a. The method of claim 1, When the saw filter chip is mounted on the saw filter head, the saw package, characterized in that the sound absorbing material is coated on the tip of the saw filter chip The method of claim 2, The saw package, characterized in that the reflected wave generated in the saw filter chip is dropped to the ground by the sound absorbing material.