Pintado was sent off after being booked twice during the second round match, which the Iron won 2-1 after extra-time at the Liberty Stadium.
The Spanish striker, 31, threw a water bottle towards an assistant referee and failed to leave the pitch quick enough - prompting the Football Association of Wales to charge him with improper conduct.
Pintado has already missed the game against Watford and must now sit out the home Championship game against Queens Park Rangers on Saturday October 3.
Pintado has already missed the league game against Watford game as a result of the customary one-match suspension.
A Swans spokesman said: "We put forward a very good case and the FAW gave us a fair hearing.
"Our case must have been very strong because charges relating to improper conduct normally carry a two-match ban and a hefty fine.''
Garry Monk and Angel Rangel were also sent off for the Swans in the match, which was won for the Iron thanks to goals from Niall Canavan and Gary Hooper.
Rangel was shown a straight red for an elbow just a minute after Pintado was marched off. The right-back apologised on Friday as he prepared to return after a three-match suspension.
'It felt as though we were playing against 14 players — 11 on their team plus the three officials," he told the Evening Post.
'It's not an excuse — as a professional you have to be very competitive but you can never hit a player."
Rangel could be punished twice, as his replacement Jazz Richards has impressed in his absence and would be disappointed to find himself demoted tot he substitutes' bench.