SBOS932C January 2020 – March 2021 THP210
The starting point for most designs is to assign an output common-mode voltage for the THP210. For ac-coupled signal paths, this voltage is often the default midsupply voltage to retain the most available output swing around the voltage centered at the VOCM voltage. For dc-coupled signal paths, set this voltage to minimum of VVS± ±2 V at VS = ± 18 V and VVS± ±1 V at VS = ± 2.5 V respectively. For precision ADC drivers, this output becomes the input common mode voltage of the ADC.
From the target output VOCM, the next step is to verify that the desired output differential peak-to-peak voltage (VOPP) stays within the supplies. For any desired differential VOPP, make sure that the absolute maximum voltage at the output pins swings with Equation 1 and Equation 2 and confirm that these expressions are within the supply rails minus the output headroom required for the RRO device.
Most designs do not run into an input range limit. However, using the approach shown in this section can allow a quick assessment of the input VICM range under the intended full-scale output condition. The TINA-TI™ simulation software can be used to plot the input voltages under the intended swings and application circuit to verify that there is no limiting from this effect. Increasing the positive and negative supplies slightly in simulation is an easy way to discover the simulated swings that might be going out of range.