Programming QFN's

[Scarr]

Hi Guys,

What is best mechanism of programming QFN's e,g, put QFN into socket program and pop it back out again.

As I have a JTAG MKII ideally a PCB with JTAG header and QFN socket with possibly a PSU would be ideal but not sure if these exist?

Steve

 

[kubeek]

Why would you want to do that? Besides, I´ve never seen a socket for a QFN package, the only sockets for SMD chips I know of are PLCC. Yes there are some hugely expensive sockets used in universal programmers, but still why would you want to use them? you still need to solder that chip to the board, so why not do it the normal way and program the chip after the board is soldered using JTAG or some form of in circuit programming?

 

[Scarr]

Kubeek,

I'm just programming some chips for someone that's why, so I'm not able to program on board.

 

[dougy83]

Yes, QFN sockets exist. I just had a look on e bay and they start at $70 for a 16 pin socket.

You could try using a PCB with the QFN footprint and connect the IC to the pad using striped conductive rubber strip ("zebra-stripe" **broken link removed**), similar to what is used to connect to the LCD in watches and calculators. Alternately you could try pressing the QFN onto the tinned footprint (only tin the pins required for programming), though this will be unreliable.

 

[jpanhalt]

3M also makes Textool sockets for QFN chips:
https://solutions.3m.com/wps/portal...NF9B3C3SI1000000_nid=R1KZCJPSC2beMXNM8F7WC9gl

No idea about pricing. I have used the SOIC 8 Textool, and it cost about $20 USD (DigiKey). Strangely, It was a little hard to find the pinout for the socket in the documentation. Maybe that has been fixed. It is a high quality socket. I used it with my programmer and never had a problem.

John