Most lenders are 640. Some go to 620 and some even advertise as low as 580 but I promise you the UW will look for ANY reason to deny loans with credit scores that low. I have seen people bounce a few checks and be told no. Trust me if your score is 700 that won't be a reason for denial. I have a program as low as 600 but again it's much tougher to get qualified. ANY late payments in the last 12 months will pretty much doom the loan. Hope this helps and please let me know if you have any questions.
PS. Your best bet is to work with a lender to review, understand and improve your credit score.
Senior Loan Officer
1ST Mariner Mortgage
Lending in all 50 states