SBOSA51 December 2020 THS4567
PRODUCTION DATA
The output common-mode loop works by sensing the average voltage between the two outputs of the main amplifier through the two 6-kΩ resistors internal resistors in Section 7.2 and comparing it against the voltage at the VOCM pin. The VOCM error amplifier then adjusts the internal bias of the main amplifier to minimize the error voltage between its input pins. The voltage at the VOCM node defaults to midsupply through the two 400-kΩ internal bias string resistors between VS+ and VS–. When using the VOCM at its default voltage, connect an external capacitor to the VOCM pin to bypass the noise from the internal 400-kΩ resistors. When the amplifier is disabled, the default midsupply bias string is disabled to save power. The THS4567 device output common-mode can also be set by driving the VOCM pin externally through a low output impedance source. Ensure that the source is capable of driving the input impedance of the VOCM pin.