SBAS672E July 2014 – June 2022 ADC3221 , ADC3222 , ADC3223 , ADC3224
PRODUCTION DATA
A typical application involving using two back-to-back coupled transformers is shown in Figure 9-3. This circuit is optimized for low input frequencies. An external R-C-R filter using 50-Ω resistors and a 22-pF capacitor is used with the series inductor (39 nH); this combination helps absorb the sampling glitches.
To improve phase and amplitude balance of first transformer, the termination resistors can be split between two transformers. For example, 25-Ω to 25-Ω termination across the secondary winding of the second transformer can be changed to 50-Ω to 50-Ω termination and another 50-Ω to 50-Ω resistor can be placed inside the dashed box between the transformers in Figure 9-3.