SLOS358C September 2011 – April 2020 THS4531
The circuit shown in Figure 71 is used to measure the transient response, frequency response and input impedance of the VOCM input. For these tests, the cal point is across the 49.9 Ω VOCM termination resistor. Transient response and frequency response are measured with RCM = 0 Ω and using a high impedance differential probe at the summing junction of the two RO resistors, with respect to ground. The input impedance is measured using a high impedance differential probe at the VOCM pin and the drop across RCM is used to calculate the impedance seen looking into the amplifier’s VOCM input.