SBOS778D April 2016 – April 2021 THS4551
One common application for the THS4551 is to take a single-ended, high VPP voltage swing (from a high-voltage precision amplifier such as the OPA192) and deliver that swing to precision SAR ADC as a single-ended to differential conversion with output common-mode control and implement an active 2nd-order multiple feedback (MFB) filter design. Designing for a 40-VPP maximum input down to an 8-VPP differential swing requires a gain of 0.2 V/V. Targeting a 100-kHz Butterworth response with the RC elements tilted towards low noise gives the example design of Figure 10-11. Note that the VCM control is set to half of a 4.096-V reference, which is typical for
5-V differential SAR applications.