寬頻放大器是通訊系統及高頻測試儀器中不可或缺的一部份。寬頻放大器是用在一段所需要頻寬中能提供一個穩定的增益。 本篇論文說明數位儲存示波器(DSO)所需的前級寬頻放大器的設計與實作。由於製程技術的提升，示波器的頻寬取樣率和精確度有了很大的進步。對寬頻放大器而言，頻寬需要達到所需的需求，但電晶體的寄生電容卻是限制頻寬的主要因素。在電路中每個信號路徑都會有個RC時間常數，這個常數常常決定了放大器頻寬。因此要使得寬頻放大器頻寬增加要設法降低RC時間常數。在這個寬頻放大器設計中，將採用並聯-並聯回授(Shunt-Shunt Feedback)的方式降低信號路徑的阻抗。 VLSI是目前世界的潮流趨勢,因此寬頻放大器的設計將採用CMOS的數位電路製程技術。整個電路是用TSMC0.6 CMOS 數位製程，佈局後模擬顯示在5V下，功率消耗為200mW，頻寬可達150MHz 晶片面積約佔1000umx1000um。 Wideband Amplifier is indispensable in some high-frequency testing instruments and communication systems. A wideband amplifier is required in a analog front end that provides a flat gain transfer within the bandwidth. In this thesis, the CMOS wideband amplifier was introduced, and implemented. Due to the processing technology improved, the bandwidth and the sampling rate of DSOs have a large development. To wideband amplifiers, the parasitic capacitors of transistors limited the bandwidth. In the circuits, every signal path has a RC time constant. This constant usually determines the bandwidth. So the topic of the wideband amplifier is to find a way to lower these RC time constants. In this wideband amplifier, we use an architecture of shunt-shunt feedback to reduce the impedances of signal-path nodes. A GAIN-VGA-BUFFER architecture is employed in the circuit design. Simulation results show the SNR is about 45dB for 100mVpp up to 100Mhz. The chip is implemented by TSMC0.6um 1P3M process. It consumes 200mW for overall circuits by 5V power supply.
