Hello,

I am a little bit confused about terminology used in ADUCM350 documentation.

1. What is the difference in AC and DC measurements. For me from perspective of ADUCM350 all generated signals are with DC levels?

2. What are the limits of DC and AC measurements of ADUCM350:

- Frequency
- Amplitude
- Any others

3. Can I use ADUCM to generate 600mVp-p sinusoidal signal and to measure impedance of test sample ?

4. Why are these limitations in amplitude when do "AC" measurement and why attenuation is exactly 1 and 40 - it is very big difference ?

5. Why there is problem to use for example 5 Ohm in TIA feedback and in this case I shall measure low impedance values?

6.. My problem is that I need to measure impedance with higher amplitude signal- Voltage and Current (>500mVp-p, >10mA) and I do not understand why there are limitations in so wide boundaries.

Thank you

Hi

3.Yes,your understanding is correct. You can generate 600 mVpp from DAC and ensure the swing across the ADC input not more than 1.5 Vpp.

5a. Yes,you need a series resistance of minimum 100 ohms for the In-AMP loop stability.If the impedance under measurement is less than 100 ohms,ADuCM350 transmit loop will become unstable.

5b. Please refer to the Table 5. Trans-impedance Amplifier Specifications ADuCM350 datasheet for TIA specifications.

Yes you can use 300 ohms.That should not be problem.

Most of the details are available ADuCM350 engineer zone ADuCM350 FAQ Index FAQ Index .For your frequency range question,you can refer to the FAQ @ADuCM350 FAQ DFT / Impedance Measurement

Thanks

Balaji