Request Component Information TN5LZ

I have an SMD component that looks like a transistor marked TN5LZ. can’t find data sheet or replacement.

Hi jfoulk,

Welcome to the Tech Forum. Do you have an image of the part available? That can be helpful in trying to identify parts. Preferably one close-up of the part itself, and another showing the parts around it is helpful so one can get a better idea of where it fits within the circuit schematic.


This is the output from a Red Lion encoder. 5 to 28 VDC input.Fairly simple, but my tester thinks it’s a resistor. I was hoping to find a spec sheet so I could select an alternative for replacement. Found a reference to it here But when I click on the data sheet it takes me to “page cannot be found”. Must be a top-secret part. And of course, I have gotten no response from Jotrin.

The link you posted, goes to the part on the Jotrin website. You have to sign in to view the datasheet.

Thanks David

Thanks for your suggestion.

Yea, I tried that. The link takes me to a page “not found”. Also have a request into Jotrin, still awaiting any response from them.

Unusual. That link you had to Jotrin said it was a WJ Communications Inc. part. From searching them online, it appears that they were an RF semiconductor products company purchased by TriQuint in 2008. TriQuint was subsequently renamed Qorvo when they combined with RFMD. I couldn’t find the part on Qorvo’s website.

Seems unlikely that this part is an RF component, given the application, so it makes me wonder about the validity of it being a WJ part.

Is it possible to see the opposite side of the board to see those connections? Also, what are the four metallic square pads near the part?


Thanks for taking your time to research this. I fear I may have misled you. I laid this chip on the board so the camera would focus on the number. Here is the real position as well as a rough schematic. I was just hoping to find the specks on the TN5LZ so I could get a close replacement. I don’t have the Max output on the signal wire, but it would go to a redlion counter or a plc input so it’s not much. Input voltage is 5 to 28 vdc. So, I guess 28 divided by 1500= 18ma now I must find all that in a SOT89 case. And hope that it is just a regular power transistor. And not something fancy like a mosfet .

Can I assume that the top side of your “photo cell” is connected to Vdc? If the circuit is that simple, then it’s most likely a BJT, as a MOSFET circuit is voltage triggered rather than current triggered and would probably have a pull-down resistor connected between your photocell and ground.

I would expect a MOSFET circuit to look something like this:


In that configuration, when current flowed through the photocell, voltage across the pull-down resistor would raise and turn on the gate. As you don’t show the pull-down resistor, it would seem to be feeding current into the base of a BJT.

Assuming it is a BJT, I’m afraid I don’t have a good idea what specs would be most important. It probably depends a lot on the characteristics of the photocell. If it has very low OFF (dark) current, then one would presume that having a higher hfe spec would be preferable, whereas if it has higher OFF current, then you would probably want a lower hfe so as to not trigger the output when no light is detected.

Obviously, you’ll want one with a higher Vce voltage than your max Vdc, and it looks like it does not need a high output current, as it only will be drawing 18mA or less.

Note that the SOT89 is also known as the TO-243AA. Here are our NPN BJT’s rated at least 30V and in the SOT89/TO-243AA package. I did a spot check on pin-outs, and all of the ones I checked matched your pin-out, but you should double check the datasheets of any part you select to verify that it matches.