The MSM7541 and MSM7542 are single-channel CODEC CMOS ICs for voice signals ranging from 300 to 3400 Hz. These devices contain filters for A/D and D/A conversion. Designed especially for a single-power supply and low-power applications, these devices are optimized for telephone terminals in digital wireless systems. The MSM7541 and MSM7542 use newly designed operational amplifiers to maintain small current deviations caused by power voltage fluctuations. The devices use the same transmission clocks as those used in the MSM7508B and MSM7509B. The analog output signal, which is of a differential type, directly drives a piezoelectric type handset receiver.