Analogue Electronics Design Case Study #1 - Section 2: Preamplifier optimized for MEMS microphone

摘要

This sub-installment in the Analogue Electronics Design article series provides a documented and commented evaluation of the original microphone preamplifier used in the Bat Detec-tor~(PLUS) project [1], and discusses solutions to optimizing it for use with the MEMS microphone examined in Section 1 of this Case Study [2]. For a full appreciation of the electronics design task done it's useful if not mandatory to refer to the circuit diagram of the microphone preamplifier mentioned a number of times, so for convenience it is shown as the highlighted section in Figure 1. We purposely reprint the entire schematic of the Bat Detector-~(PLUS) to explicitly show the way the preamplifier is: 1. driven (from the microphone connected on K1) 2. loaded (by IC4A) 3. powered (symmetrically at ±4.5 V by IC1).