KCC Quizzes AQQ303 about the radius of a circle
1. Quote of the month: "When I die, I want to die like my grandfather who died peacefully in his sleep. Not screaming like all the passengers in his car" - Will Rogers
2. Quiz AQQ304 about finding the radius of a circle
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| SLA Status | Assignee | Support Status |
|---|---|---|
| SLA Closed. | Open | |
ADG508F
Production
The ADG508F and ADG509F are CMOS analog multiplexers, with the ADG508F comprising eight single channels and the ADG509F comprising four differential channels...
Datasheet
ADG508F on Analog.com
Dear all,
The trouble occurred in our product using ADG508F.
It is Open between input and output in low temperature. (About -10 degrees C)
*I am still seeing the phenomenon only by one individual.
*We are applying +4.5V,-4.5V to Vdd,Vss.
Q1) Possibly, is supply voltage too low?
Or is it failure of device?
Q2) In a data sheet, it seems that there is no operation supply voltage range spec.
Please let me know the recommendation supply voltage range.
Best Regards,
DMN
Hello DMN,
±4.5V is quite low operating voltage, but you should still have a signal range of about ±3V.
What voltage is the signal you are trying to pass?
Regards,
Sean
Dear Sean,
Input voltage when I see the phenomenon is about 0.2V.
BR,
DMN
Hello DMN,
Seanbrown has already remarked that +-4.5V is maybe too low. The figures in the datasheet show voltages above +-5V, which you should try.
E.g: Figure 12. starts at a power supply of 10V and fig. 5. gives us the hint that the on-resistance increases as you decrease the supply voltage.
Is the output of your multiplexed channel loaded with a low resistance? Maybe Ron is already in the range of some thousand ohms.
Regards,
Dear r.daemon,
Thank you for the comment.
I also saw the figure.
The phenomenon does not occur at positive temperature.
It begins to occur from less than about -5 degree C.
If Fig.5 and Fig.8 are seen, Ron at when is likely to be 500ohms or less.
BR,
DMN
Maybe you are running the device at the breakover point with -10°C and only +-4.5V supply voltage.
Can you try, just for a test to increase the supply voltage?
Regards,
Dear r.daemon,
Now, the device is not in my place.
My customer has it now.
This phenomenon occurs only in that one device.
I want to know whether it is the usage depending on which this is not allowed on specification.
BR,
DMN
Hello DMN,
What is the digital voltages used to control the device?
I believe the issue may lie in the internal digital threshold not being met at lower temperatures. If you can, I suggest increasing the voltage of the digital control signal to VDD.
Regards,
Sean
Dear Sean,
Thank you for the suggestion.
It is not now possible though I want to try it.
An attached file is the result of being measured by my customer.
From the specification of this device, if this behavior is strange, I will request fault analysis.
Please tell me your advice.
Best Regards,
DMN
Hello DMN,
I don't think this behavior is strange and fault analysis will not be required.
The device uses an internal VCC generator to ensure the digital input level is 2.4 V. This generator requires a minimum VDD = 8V. If VDD gets lower than this, then to ensure operation of the device across all temperatures, the digital logic should be driven to VDD.
In the file you have attached, the digital input voltage is 3.3V. I recommend putting this up to 4.8 = VDD.
Regards,
Sean
Dear Sean,
Your comment is heavy for me.
And it seems to it that it is not described by the data sheet.
Or if there are materials written about it, please tell me.
I have to inform my customer of it.
Best Regards,
DMN
