JAJSH87D April 2015 – April 2019 ADS54J60
PRODUCTION DATA.
Typical applications involving transformer-coupled circuits are discussed in this section. To achieve good phase and amplitude balances at the ADC inputs, surface-mount transformers can be used (for example, for frequencies up to 300 MHz, ADT1-1WT or WBC1-1 can be used and for higher input frequencies TC1-1-13M+ can be used). When designing dc driving circuits, the ADC input impedance must be considered. Figure 149 and Figure 150 show the impedance (ZIN = RIN || CIN) across the ADC input pins.
By using the simple drive circuit of Figure 151, uniform performance can be obtained over a wide frequency range. The buffers present at the analog inputs of the device help isolate the external drive source from the switching currents of the sampling circuit.