PCM Codec-Filter

TheMC145554, MC145557, MC145564, and MC145567 are all per channel PCM Codec–Filters. These devices perform the voice digitization and reconstruction as well as the band limiting and smoothing required for PCM systems.They are designed to operate in both synchronous and asynchronous applications and contain an on–chip precision voltage reference. The MC145554(Mu–Law) and MC145557 (A–Law) are general purpose devices that are offered in 16–pin packages.

MC145554/57 (16–Pin Package)

• Fully Differential Analog Circuit Design for Lowest Noise

• Performance Specified for Extended Temperature Range of – 40 to + 85°C

• Transmit Band–Pass and Receive Low–Pass Filters On–Chip

• Active R–C Pre–Filtering and Post–Filtering

• Mu–Law Companding MC145554

• A–Law Companding MC145557

• On–Chip Precision Voltage Reference (2.5 V)

• Typical Power Dissipation of 40 mW, Power Down of 1.0 mW at ± 5 V

MC145564/67 (20–Pin Package) — All of the Features of the MC145554/57 Plus:

• Mu–Law Companding MC145564

• A–Law Companding MC145567

• Push–Pull Power Drivers with External Gain Adjust

• Analog Loopback