The ADS774JE is a high-precision ADC, and its performance can be affected by the PCB layout and component placement. It is recommended to follow a star-grounding scheme, keep the analog and digital grounds separate, and place the ADC close to the analog signal sources. Additionally, use a solid ground plane and avoid running digital signals near the analog signals.
The ADS774JE can exhibit self-heating due to its internal power consumption, which can affect its accuracy. To minimize this effect, ensure good thermal conductivity between the device and the PCB, and avoid operating the device at high temperatures. The self-heating effect can be estimated using the thermal resistance (RθJA) specified in the datasheet, and its impact on accuracy can be compensated for using calibration techniques.
The recommended input impedance for the ADS774JE is 1 kΩ or less. A higher input impedance can lead to signal attenuation, distortion, and increased noise. It is essential to ensure that the input signal source has a low output impedance to maintain the ADC's performance and accuracy.
A suitable anti-aliasing filter for the ADS774JE should have a cutoff frequency below the Nyquist frequency (fS/2) and a stopband attenuation of at least 40 dB. The filter should be designed to minimize signal distortion and attenuation, and its phase response should be considered to avoid signal degradation. A simple RC filter or a more complex active filter can be used, depending on the specific application requirements.
The external reference voltage for the ADS774JE should be stable, low-noise, and have a low temperature coefficient. The reference voltage should be chosen based on the desired ADC resolution and the input signal range. A high-quality reference voltage is essential to maintain the ADC's accuracy and linearity, and its noise and drift can directly affect the ADC's performance.
ADS774JE datasheet
by Texas Instruments
