Holy Paladin (3.5e Alternate Class Feature)
From D&D Wiki
Some Paladins prefer to lose some offensive power so they can better defend themselves
Replaces: Smite Evil
Benefit: Holy Armor (Ex): At 1st level, A holy paladin gains a +1 sacred bonus to AC and gains DR equal to her charisma modifier. The bonus to AC increases by 1 at 5th level and every 5 levels after that, for a total of +5 at 20th level.