ADC122S625 Datasheet, PDF (18/20 Pages) National Semiconductor (TI) – Dual 12-Bit, 50 kSPS to 200 kSPS, Simultaneous Sampling A/D Converter

application are conveniently powered by the same +5V power
supply, keeping circuit complexity and cost to a minimum.
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FIGURE 12. Interfacing the ADC122S625 to a Current Transducer
6.3 Bridge Sensor Application
Figure 13 shows an example of interfacing the ADC122S625
to a pair of bridge sensors. The application assumes that the
bridge sensors require buffering and amplification to fully uti-
lize the dynamic range of the ADC and thus optimize the
performance of the entire signal path. The amplification stage
for each ADC input consists of a pair of opamps from the
LMP7704. The amplification stage offers the benefit of high
input impedance and potentially high amplification. On the
other hand, it offers no common-mode rejection of noise com-
ing from the bridge sensors. The application circuit assumes
the bridge sensors are powered from the same +5V power
supply voltage as the analog supply pin on the ADC122S625.
This has the benefit of providing the ideal common-mode in-
put voltage for the ADC122S625 while keeping design com-
plexity and cost to a minimum. The LM4132-4.1, a 4.1V series
reference, is used as the reference voltage in the application.
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FIGURE 13. Interfacing the ADC122S625 to Bridge Sensors
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