Part Number: TMS320F28P650DK
Other Parts Discussed in Thread: TMS320F28375S, OPA2376
Tool/software:
Hi,
We are working with the TMS320F28P650DKPZP microcontroller and using its 16-bit single-ended ADC. The system clock is set to 200 MHz, and the acquisition window (ACQPS) is configured for 512 cycles.
We observed significant noise in the ADC readings in Case 1 and Case 3 (see attached image)— approximately 80–100 mV peak-to-peak over the average signal. However, in Case 2, the noise is minimal, around 3–4 mV peak-to-peak over the average.
I have already tested with different sample-and-hold durations, but it did not resolve the issue. Interestingly, when the same signals are routed to another board with a TMS320F28375S (12-bit ADC), the ADC readings exhibit very low noise.
The ADC reference voltage is stable and shows no signs of noise. I'm using the OPA2376 op-amp for analog signal conditioning.
Could there be any theoretical or practical impact on the input signal during ADC sampling with this controller? Based on theory, there should be no such influence, but the behavior suggests otherwise.
Best Regards,
Raju Baddipadige
