Part Number: ADS1278-SP
One of my customer is having issue with DGND to AGND resistance, in the device the resistance @pin 34 (DGND) to any AGND pin is 10E. Is this correct?
( The device is mounted on PCB and customer is having separate AGND and DGND, for checking resistance they removed shorting b/w the grounds).
What should be ideal resistance between AGND to DGND pins, is it open or short (internally).
Can you please help with your inputs.
Regards, Shinu Mathew.
AGND and DGND are internally isolated from each other, but have a parasitic diode connection between them. For a voltage potential less than 0.3V, the impedance should be very high, but once the voltage exceeds about 0.6V, it will appear very low due to the forward current through the diode.
Regards,Keith NicholasPrecision ADC Applications
We are glad that we were able to resolve this issue, and will now proceed to close this thread.
If you have further questions related to this thread, you may click "Ask a related question" below. The newly created question will be automatically linked to this question.
In reply to Keith Nicholas:
Thanks for the inputs.
Regards, Shinu Mathew.
In reply to Shinu.V.Mathew:
Can the parasitic diode formation is bidirectional ? Since observe same impedance in both forward and reverse diode mode.
Yes, the parasitic diode looks like two diodes that limits the voltage from AGND to DGND from +0.3V to -0.3V, per the ABS specs in the datasheet.
Thanks for the reply.
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.