I am building my first project and I need to make a change to the design, after I had the boards made. The subject line says it all, but here are the details:

I built a brake-light modulator for my motorcycle. I use the brake light voltage to raise a digital pin on a pic to run the modulation code. I made the mistake of using a resistor voltage divider as a digital input. Everything tested on the bench, but the bike was not available to test. The divider uses a 10k and 4.7k 1206 form-factor resistors. When the bike is running, the brake light flashes quickly and generally misbehaves.

I plan on fixing by replacing the 10k with a 22k, and replacing the 4.7k (to ground) with a 3.3v zener. In order to salvage the boards, I need to find a zener that will mount on a 1206 pad.

My search finds only 1 product made by Taiwan Semiconductor and sold by (but not stocked) by Mouser. I hate not having a choice.

So, if anyone knows of another option, please let me know. I am hoping that there are other form-factors that might work acceptably on a 1206.

I appreciate any assistance or advice.

 

Try a Zener in an SOT-23 package. It may fit good enough. Like one of these:
https://www.digikey.com/products/en...=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25

If not just use a 1N5226 by bending the leads very carefully.

 

OOPS!
Should be 3.3V!!! NOT 4.7V.
But the same applies.

Leave both resistors there as you need a pull down, and add a zener on top of the grounded one to limit the volts.
Both resistors could be 2K2 and use a 4V7 resistor.
Do an Ebay search for... "4.7V SMD Zener"
(These are Australian Ebay results.)

 

Thanks. I guess I can try to mount it at an angle.

 

OOPS!
Should be 3.3V!!! NOT 4.7V.
But the same applies.

Leave both resistors there as you need a pull down, and add a zener on top of the grounded one to limit the volts.
Both resistors could be 2K2 and use a 4V7 resistor.
Do an Ebay search for... "4.7V SMD Zener"
(These are Australian Ebay results.)
View attachment 127162

Thanks for reminding me about the pulldown. I saw those zeners, but they look nothing like my 1206 form-factor resistors, so I passed them by. Now I need to figure how to have both a resistor and a zener on the pad. What do you think of the possibility of using 2 through-hole devices soldered across the pads? I think I can do that.

 

It is easy to just solder the zener on top of the resistor. I often do this to add a capacitor across the resistor for extra bypassing.