A Highly Desensitized, Wide-Band Monolithic Amplifier

An all-diffused monolithic feedback triple with a maximum bandwidth of 50 MHz, 40 dB of feedback, and gain adjustable from 34 dB to 52 dB is described. Harmonic distortion is less than 0.15 percent at 0.5 MHz and gain variation is less than /spl plsmn/0.25 dB from -55/spl deg/C to +125/spl deg/C. Detailed analysis of the amplifier performance is carried out and an accurate design technique based upon transistor models is developed. A distributed base model is introduced which results in prediction of open loop gain and phase to within 10 percent of measured values at all frequencies below 200 Mc/s.