  We present an analysis of CMDs of three intermediate-age LMC clusters, namely
NGC 2173, SL 556 and NGC 2155. The main goal of our project is to investigate
the amount of convective core overshoot necessary to reproduce the CMDs of
relatively metal-poor, intermediate age stellar populations. We conclude that a
moderate amount of overshoot and some fraction of binary stars are essential
for reproducing the observed shapes around the turnoff in the CMD's of all
three clusters: unresolved binary stars fill in the expected core contraction
gap, and make a unique sequence near the gap, which cannot be reproduced by
single stars alone, even with a larger amount of overshoot. From our overall
analysis such as, shape of isochrones, star counts, color distribution, and
synthetic CMD comparisons, we conclude that overshoot ~ 20% of the local
pressure scale height best reproduces the CMD properties of all three clusters.
The best age estimates are 1.5, 2.1 and 2.9 Gyr for NGC 2173, SL 556 and NGC
2155, respectively.
