ZHCSG25E January 2017 – December 2022 OPA1677 , OPA1678 , OPA1679
PRODUCTION DATA
The preamplifier circuit shown in Figure 8-5 operates the OPA1678 as a transimpedance amplifier that converts the output current from the electret microphone internal JFET into a voltage. Resistor R4 determines the gain of the circuit. Resistors R2 and R3 bias the input voltage to half the power supply voltage for proper functionality on a single-supply.