MONOLITHIC REGULATED SELF-BIASED HEMT MMICS

This work benchmarks the first demonstration of a monolithic HEMT IC d esign which incorporates active regulated self-bias. The HEMT current regulator design consists of integrating an op-amp in a feedback confi guration with the LNA to achieve gain, noise figure, and de bias perfo rmance which is tolerant to threshold variations due to the HEMT proce ss. The HEMT LNA bias current can be maintained to within +/-3% variat ion over a process threshold variation (V-gs) of +/-0.5 V. The bias ci rcuitry regulates the bias current to within 1.5% over a 100 degrees C temperature range. The amplifier has a nominal gain of 10 dB and a no ise figure of 2.5 dB over a 1-10 GHz bandwidth. Across several wafers with a threshold voltage spread of 0.5 V, the regulated LNA maintains repeatable gain and noise figure which varies by less than 1 and 0.75 dB, respectively. The monolithic regulated self-bias technique can be integrated with other HEMT MMIC's in order to improve the performance and reliability, as well as to reduce the cost and weight of Integrate d Microwave Assemblies (IMA's).