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[SOLVED] Mechanical relay to photomos relay.

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i200yrs

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Hello all, would like to ask if there's anything i need to consider to convert mechanical relay to photomos relay...thanks a lot.
 

Hi,

A general, but always true recommendation: Read the datasheet(s) and keep on the specifications.
If you do so you will be on the safe side.

If you stress the contact side with overvoltage, then a semiconductor device will react more critical.

Klaus
 

Question 1: Voltage and current levels to be switched.

Question 2: Nature of load, purely resistive, reactive, tungsten, motor?

Question 3: Details of drive circuit. AC or DC? Voltage available.

Because depending on your answers, in some instances it may be feasible, but in others not.
 

Original: mercury relay have part number is MPD-2011SG .
Replacement: PhotoMOS part number AQV255G3SX.
See attached files for the datasheet.

Merc Relay
Load current Max = 2A
Voltage Max = 100Vdc
Coil Vdc = 8 to 11Vdc

Photomos Relay
Load current Max = 2.2A
Voltage Max = 100Vdc
Coil Vdc = 8 to higher (calculated series resistor)


This relays is use for APU board in automatic test equipment for semiconductor wafer test.
APU means analog pin unit (voltage and current source)
Function of AAPU is are:
Force voltage measure current,
Force current measure voltage,
Voltage measure and Hi-Z mode
 

Attachments

  • MDP-2011SG.pdf
    104.7 KB · Views: 70
  • photomos.pdf
    161.9 KB · Views: 71
My concern, for this particular application, could be the leakage current.
 

Hi,

I agree with schmitt-trigger.

You don´t choose an ATE relay not by the load only, but additionally by your measurement requirements.

Whatever you are interested in to get good quality measurement results:
* Leakage current
* linearity, distortion and noise
* additional capacitance (referred to which node)
* ....

We can not know this.

Klaus
 

My concern, for this particular application, could be the leakage current.

Yah you're right...I installed the photomos in replace with mercury relay...and I got the failure saying expect current 1mV and read 149mV.
So as you implied, photomos is not a good replacement for the application.
Well guys, any suggestions on how to find replacement for this mercury relay? Thanks a lot.
 
Last edited:

Hi,

and I got the failure saying expect current 1mV and read 149mV.
Current <--> mV ?
Current = A
Voltage = V

Well guys, any suggestions on how to find replacement for this mercury relay? Thanks a lot.
If you want us to help, you need to give us the specifications.

Otherwise we need to guess. And guessing us "try and error"... you don't need us for this.

Btw: there's a good chance that the leakage current error is caused by soldering residuals.
ATE equippment needs to be cleaned very carefully.

Klaus
 

Hello Mr. KlausST...the attached file is the actual test results for good unit....and also the circuit of my photomos....I add diode for protection, am not sure if it is necessary.

photomos_ckt.PNGleak_photomos.PNG
 

Hi,

Don't know how the schematic is related to your problem(s).

Klaus
 

Hi,

Don't know how the schematic is related to your problem(s).

Klaus


Actually am just sharing the schematic, recommended from the site doesn't have diode, i added it for protection.
I believe this gonna be a tough job for me to resolve the leak issue...
 

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