So after staring at a few ICs today, I was wondering what the "e3" or "e4" stands for on the top of an IC. For example, here is an e3:

enter image description here

  • \$\begingroup\$ interesting -- i've never noticed this! \$\endgroup\$
    – Jason S
    Commented Sep 13, 2011 at 13:52

1 Answer 1


It is regarding the lead content or plating finish. Here is an excerpt from IPC/JEDEC J-STD-609:

e0 - contains intentionally added lead (Pb)

e1 - SnAgCu (shall not be included in category e2)

e2 - Sn alloys with no Bi or Zn excluding SnAgCu

e3 - Sn

e4 - Preplated (e.g., Ag, Au, NiPd, NiPdAu)

e5 - SnZn, SnZnx (no Bi)

e6 - contains Bi

e7 - low temperature solder (\$\le\$ 150C) containing Indium (no Bi)

e8, e9 - unassigned

  • \$\begingroup\$ Oh wow, excellent. Thank you for that great answer. John. \$\endgroup\$
    – user1307
    Commented Apr 29, 2010 at 8:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.