Texas Instruments DEM-OPA-SC-1A-EVM, User Manual, Page: 4 / 10

Measurement Tips
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4 SBOU232 – October 2019
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DEM-OPA-SC-1A-EVM Evaluation Module
5 Measurement Tips
This demonstration fixture, with the component values shown, is designed to operate in a 50- Ω
environment; most data sheet plots are obtained this way. It is easy to change the component values for
different input and output impedance levels. However, do not use high-impedance probes; they represent
a heavy capacitive load to the op amp, and will alter the amplifier response. Instead, use low-impedance
(
≤ 500 Ω ) probes with adequate bandwidth. The probe input capacitance and resistance set an upper limit
on the measurement bandwidth. If a high-impedance probe must be used, place a 100- Ω resistor on the
probe tip to isolate its capacitance from the circuit.