Design Of SAW Drive Circuit In Digital TV Tuner

In the single frequency conversion digital TV tuner, the signal from mixer need filtered by surface Acoustic wave filter. However, the signal will be greatly attenuated, and the signal amplitude cannot satisfy next stage circuit. Therefore, it is need one stage amplifier before surface Acoustic Wave filter, which can compensate insertion loss.Based on the digital TV tuners system and the surface Acoustic Wave filter, 18dB voltage gain, noise finger less than 15 dB, minimal frequency range is 32 MHz-40MHz bandwidth CMOS intermediate frequency amplifier is designed for the surface Acoustic Wave filter's drive circuit. The SAW drive circuit was designed in this paper which consists of three parts: input buffer, differential amplifier, negative feedback circuit. Negative feedback circuit is the main body of SAW drive circuit which is composed by operation amplifier and feedback network, its function is to realize output impedance matching and electric circuit stable gain. Input buffer isolates this stage circuit and next stage circuit. Differential amplifier and negative feedback circuit realize SAW drive circuit gain together.The circuit is designed using IC design software offered by MENTOR Corporation. The schematic was input using MENTOR Corporation's DA-IC. The simulation tool is ELDO. It is one kind of SPICE simulation software, moreover, it has very good compatibility with other SPICE simulation software. The layout of the circuit is designed by IC-STATIONS layout design software.This design uses 0.18um CMOS technology which is provided by the Semiconductor Manufacturing International Corporation, The technology supply voltage is 3.3V.