A Wide Band Oscillator Design Based on Bi-CMOS Active Load Differential Amplifier

In this paper, we present a VHF and UHF bands oscillator which mainly composed of a Bi- CMOS active load differential amplifier (Diff. amp). We use H-spice and ADS to verify that the active load differential amplifier oscillator output frequency is 817.1 MHz at 3.3 volts power supply under CIC 0.35μ:m-GeSi process. We also use discrete devices on bread board to prove the circuit is an oscillator circuit. Those experiments show such an oscillator can work stably from 2.7 to 6.0 volts. Their output frequency will be 128.7 MHz, 176.4 MHz under 2.7 volts and 6.0 volts respectively. We use FFT (Fast Fourier Transform) diagram to analyse these oscillators and shows SNR (signal-to-noise ratio) values. Finally, those experimental results reveal that the oscillator is a nice voltage controlled oscillator (VCO) and also have good SNR characteristics.