UDN2981 Replacement (obsolete now)

Hi all,

As part of a pcb I'm designing, I need to control around 6 12v LEDs from arduino pins. Since the LEDs are on an existing board with a common earth, I must have 12v switching rather than switching to ground. I had previously been directed to the UDN2981 chip which looks perfect, but my PCB manufacturer says this chip is now obsolete and they can't get hold of it. Can anyone help me with a replacement chip that would do the job? The PCB manufacturer says they can't identify a replacement PN..

Thanks,

Nick

You could look at using the Texas Instruments part TLC59213 which is still available at places like Mouser.com.

Datasheet

I know pinout isn't the same, nor is the function of it identical... but its close enough that only a small bodge on the PCB would likely be needed.

Fantastic, thank you I will ask them whether they can use this part

Six P-channel FETs in SMD are not going to have too large a footprint, though you then need six N-channel or a TPIC6x595 device.

Actually, what you want are six of these! :grinning:

And some resistors.

pwillard:
You could look at using the Texas Instruments part TLC59213 which is still available at places like Mouser.com.

Datasheet

I know pinout isn't the same, nor is the function of it identical... but its close enough that only a small bodge on the PCB would likely be needed.

Hi there, are you able to please clarify what the bodge needs to be? I'm just looking at this now in detail and I see that the function is not quite the same - how would you make it work as a simple source driven transistor array? I'm not sure what to do with CLK or CLR... The Datasheet is a little confusing...

Thanks,

Nick

Paul__B:
Six P-channel FETs in SMD are not going to have too large a footprint, though you then need six N-channel or a TPIC6x595 device.

Actually, what you want are six of these! :grinning:

And some resistors.

Forgive my ignorance but how would I use these? Could I not just use 6 NPN transistors? Can they be driven from a 3.3v arduino pin, and if so how do you size the required resistor?

Thanks!

If you want NPN transistors as level-shifters up to 12V then it depends whether your main high-side
switching devices are PNP (current driven) or p-channel FETs (voltage driven).

For instance for p-channel switches see posting #4 in this thread: https://forum.arduino.cc/index.php?topic=555862.0

Thanks Mark,

Switching device is a teensy arduino and it will be high side with a single led and resistor downstream. Would this be current or voltage driven??