looking for a PIC

[dhouston]

I need to replace a Sonix SN8P2501BSG SOP14 µController with a PIC, preferably one that I can use the ds30 loader with.

If I can find a PIC with Vdd on Pin 4 and Vss on Pin 11, I can probably handle the rest.

Microchip used to have a page listing all PICs with pin counts, etc. but they seem to have remodeled and it is now impossible to find anything that you do not already have a model number for.

A volunteer organization gives emergency phone dial units with pendants to those who need them. They frequently get units back without the pendant. There's a Linear garage door keyfob with the right RF frequency and, if I can find a suitable PIC, I can write a program to send the needed RF codes and they'll have a way to replace the pendants (pendant no longer made).

[spcw1234]

This might help, but those power pins are going to be tough to match.

http://www.microchip.com/stellent/id...cName=en544123

[dhouston]

Shawn, thanks for the link.

I guess Microchip thinks that's an improvement - I sure don't. It is better than nothing but not by much.

Oh well, even if I found a chip, Digikey has discontinued their print catalog, making it just short of impossible to buy anything from them.

[Jumper]

Hi,

Get any PIC in a really small package and surface mount that one on a break-out board that you later surface mount on the current footprint on your pcb. Or if you have a thru hole foot print just make a board with pins that you can solder in that place or use a IC-holder.

Then you can use any pic you like and still get the pins to be in the correct place

[dhouston]

@Jumper - the SOP14 SMD chip is surrounded by other components and there is minimal headroom so a breakout board wouldn't work even if I designed one with the correct pin mapping. Plus, the (elderly) people who will have to do the work are total novices who could probably handle direct replacement of an SOP14 size chip (with a hot air rework station) but not much else as far as SMD.

But, it turns out the Sonix chip in the keyfob is powered by 12V directly to the chip so I will have to find another way to do this.

[Jumper]

No problem.. I was more thinking of that you make the board and mount the LLC package of the pic... and then put a drop of epoxy on the top to protect it.. The board will be similar in size (just a litte bit more narrow than the normal SOP-14 leg witdh)

Then the board has plated pads on the side that allows it to be soldered on the side using a regular soldering iron.

I have a similar component today and I can upload a picture tomorrow to show what it looks like

[Demon]

...Oh well, even if I found a chip, Digikey has discontinued their print catalog, making it just short of impossible to buy anything from them.

Why? Your ISP blocks their site? Their search feature works pretty good, haven't had a problem yet.

Robert

[ScaleRobotics]

I don't know much about them, but Microchip has the HV series, like the PIC16HV610 and PIC16HV616 for "high voltage" applications. These can run to 15 volts. They come in a 14 pin, but you would have to do something like Jumper mentions to get the pins in the right places.

[Jumper]

The hard-core way I use is I place normal hole pads for a double sided PCB in suitable positions and then make the board size so the milling machine cuts tru the middle of the pads leaving a half circle plated pad with a half hole that is also plated to be used for soldering.

I think there are other ways too but this one seems to work quite ok. If you choose a really tiny pic package then it could be possible.

[Demon]

If this goes in a keyfob, how about just making an entire new PCB?

It would mean a bit more work on your part, but be simple plug and play for the users.

And where does 12V comes from in a keyfob? That's a lot of batteries, but you have a holder for only a small one?

Robert

[ScaleRobotics]

Here's a picture of a circuit board with what Jumper is suggesting:

[dhouston]

I've seen/have a few such PCBs and assumed I could use half a normal pad - just never needed to try it - sorta fits as I'm only about half-normal, myself.

A new PCB would require a few $K for FCC approvals and I doubt these volunteers want to spring for that.

I've also suggested they look at alternatives which I've listed below in case anyone has an interest.
http://want2care.com/guardian_alert_911.html
http://cordlessworkz.com/telemergenc...rt-device.aspx
http://www.directsalesinc.com/noname2.html
http://www.elderstore.com/wireless-e...ne-dialer.aspx
http://www.amazon.com/Help-Hand-Emer.../dp/B00012K246

[BH_epuk]

As a very different suggestion have you looked at the Si4010 by siliconlabs ?

Just starting on a project using this, SiLabs do supply Gerber files for a keyfob, not sure what the usage limits are on this though

[dhouston]

As a very different suggestion have you looked at the Si4010 by siliconlabs ?

It would also need FCC approval which is far too costly.

[Demon]

I'm curious, using a different micro would not require FCC approval?

Robert