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The ADS78x1EVM showcases the 12-bit, 4-MSPS (ADS7881) and 14-bit, 3-MSPS (ADS7891) ADCs. The ADS7881 and ADS7891 devices include a capacitor-based successive-approximation register (SAR) ADC with inherent sample and hold. These devices offer either a 12-bit or 14-bit parallel interface. Both devices offer byte mode operation that enables easy interface with 8-bit processors. They also have a pseudo-differential input stage and a 2.5-V internal reference.
This evaluation module serves as a reference design and a low-cost method to test these converters in the end application. The following sections describe the pin outs of the various analog, power, and digital connectors and power requirements.
Table 1-1 lists documents related to the ADS78x1EVM.
The ADS78x1EVM includes the following features:
The ADS7881 and ADS7891 ADCs have both a positive and negative analog input pin. The negative input pin, which has a range of –200 mV up to 200 mV is shorted on the board. A signal for the positive input pin can be applied at connector P1, pin 2 (as shown in Table 1-2) or at the center pin of the SMA connector J2.
Connector.Pin#(1) | Signal | Description |
---|---|---|
P1.2 | +IN | Noninverting input channel |
P1.4 | Reserved | — |
P1.6 | Reserved | — |
P1.8 | Reserved | — |
P1.10 | Reserved | — |
P1.12 | Reserved | — |
P1.14 | Reserved | — |
P1.16 | Reserved | — |
P1.18 | Reserved | — |
P1.20 | REF+ | External reference input |