FX465

Features:

Low-Voltage (3-Volt) Supply
47 Programmable Sub-Audio Tones + NOTONE
Meets MPT1306 and TIA/EIA 603
High Voiceband/CTCSS Isolation
Separate Sub-Audio and Rx/Tx
Audio Paths and Filtering




Application

Mobile Radio Systems
Community Base Stations
"Sports Radio" (Japan)
Sub-Audio Signalling and Selective Calling
Status and Alarm Systems
Amateur Radio




Specifications

Exceeding the maximum rating can result in device damage. Operation of the device outside the operating limits
is not implied.
Supply voltage -0.3 to 7.0V
Input voltage at any pin (ref V_SS = 0V) -0.3 to (VDD + 0.3V)
Sink/source current (supply pins) +/- 30mA
(other pins)+/- 20mA
Total device dissipation @ T_AMB 25°C 550mW Max.
Derating 9mW/°C
Operating temperature range: FX465 D5 -40°C to +85°C
Storage temperature range: FX465 D5 -55°C to +125°C




Description

The FX465 is a 3-volt, half-duplex predictive Continuous Tone Controlled Squelch System (CTCSS) encoder/decoder microcircuit. The FX465 has integral voice-band filtering for prefiltering of Tx audio and the rejection of the CTCSS tone in receive.

Under µProcessor control, the FX465 will encode and decode any one of 47 sub-audio frequencies (+NOTONE) in the range 67.0Hz to 254.1Hz. Tone frequencies and all functional commands can be loaded to the device in either pin-selectable 8-bit parallel or serial format.

A separate, Rx/Tx voice-audio path is available with a highpass (sub-audio reject) filter automatically placed in the relevant Rx or Tx voice line.

The Rx sub-audio (CTCSS) path contains a (selected tone frequency) bandpass filter and period detector providing a logic level output (Rx Tone Detect) to indicate a successful decode operation.

Rx "Press to Listen" (PTL) and Tx "Squelch-Tail Elimination" functions are available in both command loading modes. The squelch-tail elimination function will provide (Tx tone) phase-reversal to minimise the annoying audio outputs that occur at the receiver on completion of a transmission.

Tone frequencies and filter accuracies are maintained by an on-chip 4.0MHz clock oscillator employing an external crystal or clock pulse input.

The FX465, which exhibits high audio and sub-audio performance with low falsing, is available in a 24-pin plastic small outline SSOP package.