Audio Filter Array


Features and Applications

  • Cellular Radio Audio Processing to NMT TACS AMPS Specification
  • Low Group Delay Distortion
  • Switched Capacitor Filters
  • On-Chip Uncommitted Amplifier
  • Xtal Controlled

  • Chip Enable Powersave Feature
  • Low-Power CMOS Process
  • Choice of Package Styles
  • Few External Components
  • Single 5-Volt Supply

The FX306 is a low-power CMOS switched capacitor filter array designed to meet the NMT, TACS and AMPS audio processing specifications. The device consists of:
  1. a 3.4 kHz low pass filter.
  2. a 300 Hz-3.4 kHz bandpass filter (low pass filter identical to that of (1) in series with a highpass filter).
  3. an uncommitted amplifier.
The two 6th order low pass filters provide a low group delay distortion path. The amplifier may be used for any specific applications such as pre-emphasis, de-emphasis, buffering, etc. An on-chip oscillator uses a 1 MHz Xtal and provides all reference clocks for the switched capacitor filters via a divider chain. Alternatively, an external clock may be used.
The Chip Enable feature is used to disable the filter sections and the amplifier, thus reducing current consumption.