It is well known that direct sequence-code division multiple access (DS-CDMA) receiver using exponentially weighted despreading function outperforms significantly receiver using rectangular despreading function. The maximum value of the signal-to-interference-plus-noise ratio (SINR) for this type of receiver is an important indicator to evaluate the bit error rate (BER) performance of the system. In this paper, we propose an improved formula obtained by using simulated annealing (SA) algorithm to calculate the maximum value of the SINR. It is shown that the results computed by the proposed formula are more accurate than the results obtained by the simplified formula available in the literature. Copyright (c) 2005 AEIT.