Hi,
I recently got the ADS5483 EVM. I would like to use the Analog Input Option 2 with DC coupled signal.
I followed the instruction for DC coupled operation at e2e.ti.com/.../1399346
- unsolder and resolder SJP4, SJP1 and SJP2.
- remove both transformers and jump the signal path across the primary and secondary side.
- solder 0 Ohms resistors on all the series elements of the filter.
- remove the C1 and C4.
The common mode input voltage is set to 2.5V from the ADC. The THS4509 is powered with single +5V.
SMA J2 is not installed.
Here is what I observed:
Looking at AMP OUT+ and AMP OUT- for 0 V apply to SMA J1 they are at 2.1V and 2.8V respectively. I would expect them to be at 2.5V. When I send a sinewave (0.5Vptp, offset 0V, 100 kHz) I see half of the sinewave cycle on both AMP OUT+ and AMP OUT- with the remaining part of the cycle at DC level 1.9V and 2.9V respectively.
What am I doing wrong?
Thanks for your help.
Mathieu.