The 821004 is a single-chip, four channel PCM CODEC with on-chip filters. The device provides analog-to-digital and digital-to-analog conversions and supports both a-law and m-law companding. The digital filters in 821004 provides the necessary transmit and receive filtering for voice telephone circuit to interface with time-division multiplexed systems. All of the digital filters are performed in digital signal processors operating from an internal clock, which is derived from MCLK. The fixed filters set the transmit and receive gain and frequency response.


  • 4-channel CODEC with on-chip digital filters 
  • Selectable A-law or μ-law companding 
  • Master clock frequency selection: 2.048MHz, 4.096MHz or 8.192MHz 
    • Internal timing automatically adjusted based on MCLK and frame sync signal 
  • Separate PCM and master clocks
  • Single PCM port with up to 8.192MHz data rate (128 time slots) 
  • Transhybrid balance impedance hardware adjustable via external components 
  • Transmit gains hardware adjustable via external components 
  • Low power +5.0V CMOS technology 
  • +5.0V single power supply 




Type Title Date
Datasheet PDF 787 KB
End Of Life Notice PDF 1.43 MB
2 items

Design & Development