3:1 for your money, when to call, when to fold?

[NYWalker]

I've been losing chips in such situation, I want to know how others hand this.


Hand: Commerce $300 Rebuy $250K GNT. 800/400/100. Fold to you at CO with 20000 (little over average), you raise to 2400 with A5o. Button is short stack tight player moved all-in for 6000. Blinds folded. Pot 6000+2400+2100=10500,3600 more to go, 3:1. But we know Button is always >ATo. It's about even to call.

Losing this hand, we are down to 1400 and short stack is up to 14000.

I guess my question is how deep our stack should be to make such call?