Design Of Hybrid Circuits For Cryogenic Sensor-Amplifier Interfaces

The design of a hybrid circuit frequency compensation module for use with various infrared instrumentation systems is discussed. The design objective is to achieve essentially the same preamplifier response over a given range of frequencies both at high-level output and at low-level output, when operating at the same temperature as a cryogenic sensor (detector). The design procedure requires that the temperature and/or voltage variation of resistor values used in the module be either (a) measured directly or (b) extracted from comparison of measured and computer-generated frequency response curves. It is found that a computer-aided design procedure using iterative analysis with an ac network analysis program results in reduced design and development time. Also, this procedure leads to a better understanding of problems associated with cryogenic sensor-amplifier interfaces.