DAC7512: DAC7512 problem

Hi Ong,

Welcome to E2E and thank you for your query. i am checking with the internal team for the answer. I will get back by end of this week or sooner.

Regards,
Uttam Sahu
Applications Engineer, Precision DACs

Hi Ong,

Just to make sure we reach the root cause properly, can you confirm that there was no change from your hardware or system side during thesse many years?

Regards,
Uttam

Hello Ong,

Could you share an oscilloscope capture of the "pulse type fluctuation" you are describing?

Also, can you explain the exact setup / conditions and measured impedance of the VDD-GND resistance you've mentioned?

Hi

1. I am using two DAC7512 on this board until 2014 year.

    I don't change H/W & F/W and I found problem is solved after only changing two DAC7512 with old version.

   ->  I checked glitch waveform and took off one chip on board and soldered new chip(of course old version) by myself..

        I checked giltch remained and took off otehr chip on board and soldered new chip(of course old version) by myself then glitch disappeared..     

2. I checked resistance between Pin 1(DAC OUT) and Pin 2(GND) on my board  found that value is different between old and new.

3. I know this chip has 0.5us glitch but  about 300us glitch shows.

    I want to attach waveform image but it's blocked by our company's policy. 

3. And I know other case happens several months ago this year  on other board.

    There DAC7512 VDD power is  voltage divided by variable resistor(10K ohm) .

    Defaut value is 2.5V but on  this condition the voltage of some DAC7512 VDD pin  is more than 4V.

    After changing new,this problem solved ..

Have a nice day 

   Ong

I want to know normal resistance values.. I need easy method to check this chip is ok or not..
1. Pin3 (VDD)- Pin2(GND)
2. Pin1(OUT)- Pin2(GND)

Hi

Are you checking?

I want to know the root cause..

regards

 ONG

Ong,

I do not have measured nominal values for these figures across a statistically significant dataset.

If we take this discussion to email is it within your company policy to share the schematic / oscilloscope captures I mentioned earlier? I think these would help us understand the issue better.

Hi Ong,

Is sharing a schematic possible?

It's not possible to share sch.

Instead..

I compared two lots.. 2016 & 2017 ..

And I find something different in resistance between DAC OUT Pin and GND.

2016 has 250Kohm -> DACs has this resistance value shows normal operation(small glitch in datasheet)

2017 has 650~800Kohm -> DACs has this resistance value shows large glitch..

Ong,

I have an inquiry out to check on the history of the manufacturing flow of this device but I doubt that anything has changed in that time period.

Can you share the exact lot trace codes (top side markings) for the two parts you looked at?

Hi Ong,

I have found some changes in the flow for the overall device family, but to really understand whether you were impacted or not I will need the top side markings. Please update this thread with that information when you can to continue pursuing this.