I want to build a speeduino board and wanted to know What alternatives can I use for
3M9580-ND
MPX4250AP-ND
497-5981-5-ND
since these are nolonger being made
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Hello dezymaccow,
Welcome to the DigiKey TechForum community.
For 3M9580-ND take a look at a similar one in part 1849-09200-71-BBGB00-ND.
For MPX4250AP-ND take a look at a similar in part MPX5700ASX-ND.
For 497-5981-5-ND there is a manufacturer recommended replacement in part 497-STP70NS04ZC-ND but we do not stock it and unfortunately I could not find a similar to match in stock. Hope that helps.
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Thank you very much mate , So with these the circuit will work normaly with no alterations right ?
Hi dezymaccow,
Regarding the pressure sensor, it will not just work without at least re-calibrating your software, and since it’s sensing range is much broader than the original (roughly 2psi ~ 101psi vs. 3psi ~ 36psi), you won’t get the same resolution in your measurements. It does look like the pinout is the same, so you would not have to change the physical connections.
The 1849-09200-71-BBGB00-ND will work just fine as a replacement.
The 497-5981-5-ND ( STP75NS04Z) has a fairly unique characteristic of having internally integrated TVS protection diodes connected between the gate and the drain and gate and source. These may help protect it in some applications. It’s notable that this feature seems to be much less commonly found in newer MOSFETs, and I have found none which have similar overall specs.
For a MOSFET which has otherwise similar specs, the STP100N6F7 might be worth consideration. To give it similar protections as the STP75NS04Z, you would have to add external TVS diodes to replace the missing internal ones.
Thank you for the information , so how ill i put the diode (to wich terminal) and what is likely to happen if I just install the MOSFET without the diodes
dezymaccow
The data sheet for the STP75NS04Z shows the TVS diode between Gate and Source , and Gate and Drain in link below . these are for circuit protection ,
Thanks Craig
thanks Craig
Hi dezymaccow,
Honestly, I would be most concerned about the pressure sensor. As I mentioned previously, the suggested replacement senses from a range of 2psi ~ 101psi with an output of 0.2V to 4.7V rather than the 3psi ~ 36psi with an output of 0.2V to 4.9V of the original sensor. This means that the sensor’s outputs will not be the same for a given pressure.
Example output characteristics of the two pressure sensors:
Output votage at 25psi Output change for 1psi change MPX4250AP 3.33V 0.1424V MPX5700AP 1.34V 0.0455V
So, your software would have to be able to account for this significant difference in output voltages for a given pressure and for the smaller change in voltage for a given change in pressure.
Regarding the MOSFET, if you install just the MOSFET without the TVS diodes, it may work just fine, but it will be somewhat more susceptible to damage from transient voltage spikes. The TVS’s help protect it from those transients. They don’t define which TVS parts they use, since they are just added as part of the silicon rather than as discrete components added separately, but based on specifications within the STP75NS04Z’s datasheet, I would say that the nearest match in a through-hole part would probably be the SA15CA-E3/54.
You would place one between the gate and drain (pins 1 and 2) and the other between the gate and source (pins 1 and 3). For best protection, you’ll want to minimize the lead lengths of each TVS, while ensuring that the leads do not make contact with each other (causing a short circuit).
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Okay thanks , on the pressure sensor I once saw a guy tuning his board using Tuner Studio (Im not not familiar with it myself) , he had an option of calibrating his board as per to the sensors specifications for example
Giving the values/readings the sensor gives and the corresponding voltage. So my question is will I be able to do the same so that the board reads the actual value
And on the Mosfets , thank you very much I now get the picture
If the software is capable of arbitrarily calibrating to whatever the sensor’s output is for a given pressure, then it should work. However, both the MPX5700ASX (horizontal port) and the MPX5700AP (vertical port) cover a wider range of pressures for essentially the same output voltage range, so a small change in output voltage represents a larger change in pressure for these than for the original sensor.
This means it will be harder for your board to resolve small changes in pressure with these sensors. If your board’s ADC has sufficient resolution, then this may not be a problem for it, as a high resolution ADC can detect smaller changes in voltage than a lower resolution ADC. However, I don’t know how important it is to resolve small pressure changes in your application, so this may or may not be important.