A radio frequency amplifier with integrated pre-filter and packaging method thereof

Abstract

The present invention proposes an amplifier circuit with an integrated pre-filter and its packaging method. A high-order LC bandpass filter is split into three filter units, which are placed on the packaging substrate, amplifier front end and amplifier stage respectively. Inside the space, its integrated frequency response is similar to that of a relatively ideal high-order bandpass filter, and its insertion loss is small, which can meet the filtering processing requirements in current mobile communications. Furthermore, in the design of the filter of the present invention, the inductance components originally distributed in the amplifier are fully absorbed, including the input series inductance, the source inductance, etc., which further saves the device area and cost.

Description

technical field [0001] The invention relates to the field of signal amplification and processing, in particular to a radio frequency amplifier integrating a pre-filter and a packaging method thereof. Background technique [0002] The traditional surface acoustic wave filter (SAW) is a kind of transducing non-conductive filter made of the piezoelectric effect of piezoelectric quartz crystal oscillator materials such as piezoelectric ceramics, lithium niobate, and quartz, and the physical characteristics of surface acoustic wave propagation. The source bandpass filter is a special filtering device made of piezoelectric materials such as quartz crystals and piezoelectric ceramics, using its piezoelectric effect and the physical characteristics of surface acoustic wave propagation. Its spectral response is similar to that of a high order LC bandpass filter. [0003] The piezoelectric effect existing in crystals with certain symmetry is the "motor" and "generator" of the surface...

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Problems solved by technology

But SAW filters have limitations: above about 1 GHz, their selectivity decreases; at about 2.5 GHz, their use is limited to applications that do not require high performance

[0007] figure 2 It shows the schematic diagram of the SKY65713 chip of Skyworks in the United States. It can be seen from the figure that it is a highly integrated RF front-end chip integrating pre-filter and low-noise amplifier. It uses two wafers inside, of which The pre-filter is a single one, and the low-noise amplifier together with the bias circuit and output matching is another one. An off-chip inductor is required from the output of the pre-filter to the input of the low-noise amplifier. Therefore, the scheme The cost is high, and the user is more complicated to use

[0008] It can be seen from the above that the cost of the existing SAW filter is relatively high, and it is difficult to be compatible with the RF amplifier of the CMOS process; and the traditional on-chip low-order LC cannot realize a resonant cavity with a high quality factor, which will cause serious insertion loss (insertion loss) , resulting in a severe deterioration of the sensitivity

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