ZHCSOR9A November 2021 – April 2022 OPA4H014-SEP
PRODUCTION DATA
Figure 8-5 shows the circuit configuration for testing the EMIRR IN+. An RF source is connected to the op-amp noninverting input pin using a transmission line. The op amp is configured in a unity gain buffer topology with the output connected to a low-pass filter (LPF) and a digital multimeter (DMM). A large impedance mismatch at the op amp input causes a voltage reflection; however, this effect is characterized and accounted for when determining the EMIRR IN+. The resulting dc offset voltage is sampled and measured by the multimeter. The LPF isolates the multimeter from residual RF signals that may interfere with multimeter accuracy.