Udc 621.396.6.181.5 Simulation of Time{delay Effects in Ultra-high Speed Amplifiers with Negative Feedback

The paper describes the simulation of delay times of high speed ampli ers in microstructures. Beyond the current standard of about 10GB/s ringing and instability{problems increase in data ampli ers with an negative feedback within a stage. There are three causes for instability of the closed loop gain: (1) a not real feedback gain (gfb) by the combined parasitic e ects of line inductances and stray capacitances (2) too many poles (n) of the inner gain (gi) and (3) too large delay times (td). Let us assume: n = 1 and concentrate on time delays. Results will be given in the case of an unity{ gain{ampli er and a current{to{voltage converter with an inner transistor ampli cation of gi;DC = 10, a cut{o frequency of fo = 10GHz.