Minimum CAS Latency based on medium timebase (MTB) units. tAAmin can be read off SDRAM data sheet.
Based on medium timebase of 0.125ns
tAAmin 
12.5ns         DDR3-800D          64h          
15ns            DDR3-800E          78h
11.25ns      DDR3-1066E        5Ah
13.125ns    DDR3-1066F        69h
15ns            DDR3-1066G       78h
10.5ns         DDR3-1333F        54h
12ns            DDR3-1333G        60h
13.5ns         DDR3-1333H        6Ch
15ns            DDR3-1333J         78h
10ns            DDR3-1600G        50h
11.25ns       DDR3-1600H       5Ah
12.5 ns        DDR3-1600J        64h
13.75ns       DDR3-1600K       6Eh