Figure 3-2 shows the schematic for the THS4541 input circuit connected to each ADC channel. The THS4541 is a high-speed, fully differential amplifier with a gain-bandwidth product of 850MHz. This circuit is configured for a gain of 5V/V and can accept both single-ended and differential inputs. By default, the THS4541 circuit is tuned for a single-ended input signal up to 1MHz with 50Ω output impedance. For other input source impedances, or for differential inputs, TI recommends to remove the termination resistors at the FDA inputs or short across them using the provided jumper.

Figure 2-2 THS4541 Fully-Differential Circuit for ADC A

The OPA320, shown in Figure 3-3, is used as the VCMOUT buffer to drive the output common-mode voltage on both ADC A and ADC B input circuits.

Figure 2-3 OPA320 Circuit to Buffer the ADS9219 VCMOUT Voltage