We must move from WM8731SEFL to WM8731CSEFL, as the original part is obsolete.

I am advised the only difference is the "introduction of copper bond wires".

Order Code WM8731LSEFL and WM8731LSELF/R changed to WM8731CLSEFL and WM8731CLSEFL/R to reflect change to copper wire bonding.

What is a copper bond wire? Does it refer to the interconnects, the solder pads or something else? Could the change affect RF emissions?


1 Answer 1


Bond wires connect the external pads to the chip die itself. Traditionally they're gold. Presumably some new manufacturing technique allows the use of cheaper copper. I doubt this will be externally detectable; maybe it makes some difference to the expected lifetime and corrosion resistance of the chip.

  • \$\begingroup\$ Thanks, so most likely RF emissions remain unchanged? \$\endgroup\$
    – SeanJ
    May 5, 2015 at 8:28
  • 1
    \$\begingroup\$ I would assume so - the wires are tiny. \$\endgroup\$
    – pjc50
    May 5, 2015 at 8:32

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