MX214 Datasheet, PDF (1/17 Pages) CML Microcircuits – Variable Split Band Inverter

DATA BULLETIN
MX214/224 Variable Split Band
Inverter
Features
 CTCSS Highpass Filter
 Good Recovered Audio Quality
 Fixed and Rolling Code Modes
 Serial (MX214) and Parallel (MX224)
Loading Options
 32 Programmable Split Points
 Half-Duplex Capability
Applications
 Mobile Radio Voice Security
 Cellular Telephone Voice
Security
POWERSAVE
LOAD / LATCH
SERIAL CLOCK
ENABLE / MUTE
CLEAR / SCRAMBLE
Rx / Tx (SER / PAR)
A0
A1
A2
A3
A4
INPUT LATCHES
EN / MUTE
CLEAR / SCRAMBLE
Rx / Tx
ROM
(SERIAL DATA IN)
Rx IN
Tx IN
EN ⋅ PS ⋅ Rx
PS
BIAS
Rx
MUTE
BIAS
Tx ⋅ PS
Tx ⋅ PS
CK3
FILTER 3
PS
BIAS
FILTER 1
CKA
CKB
CTCSS
FC2
C5
Rx
FC1
Tx
C6
1MHz
OSC
XTAL / CLOCK
XTAL
1MHz
CLOCK
DIVIDER
CKA FC1 FC2 PS
CK3
CK4
CLOCK
DIVIDER
CKB CK_B
CLOCK
SWITCHING
Rx / Tx
VDD
VBIAS
VSS
Rx
Tx
PS ⋅ EN ⋅ Tx
Rx
Rx
Tx
FILTER 4 SCRAMBLE
CK4
Σ
FILTER 2
CKA
Tx
CK4
Rx
CLEAR
BIAS
Tx OUT
PS + EN ⋅ Tx
BIAS
PS ⋅ MUTE ⋅ Rx
Rx OUT
BIAS
BIAS
PS + EN ⋅ Rx
The MX214/224 Variable Split Band Inverters are designed for mobile and cellular radio voice security
applications. Digital control functions are loaded serially into the MX214. The MX224 is loaded in parallel.
The MX214/224 ICs include a highpass filter that rejects subaudio frequencies, ensuring full CTCSS
compatibility. This CTCSS filter is not included on the earlier generation MX204 VSB Inverter.
The MX214/224 splits the voiceband (300-2700Hz) into upper and lower subbands, and inverts each subband
about itself. The ‘split point’ (defined as the frequency where the voice band is subdivided), is externally
programmable to 32 distinct values in the 300 to 3000Hz range. In the ‘fixed code’ mode, a single point is
used. Fixed mode operation nets approximately 4 mutually exclusive secure channels.
In ‘rolling code’ mode, the split point is changed many times per second, usually under control of a
microprocessor. Rolling code scrambling requires synchronization, offers higher security than fixed code
operation, and provides a much greater number of mutually exclusive secure channels.
The MX214/224 offers a recovered audio product close to that of a telephone. The on-chip ‘ Mute’ function is
useful when implementing rolling code continuous synchronization schemes. ‘Powersave’ and
‘Clear/Scramble’ controls are also included on-chip. Timing and filter clocks are derived internally from an
on-chip 1MHz reference oscillator driven by a 1MHz crystal or clock pulse input.
The MX214 and the MX224 operate from a single 5.0V supply and available in the following packges:
22-pin CDIP (MX214J/MX224J), 22-pin PDIP (MX214P/MX224P), and 24-pin PLCC (MX214LH/MX224LH).

1998 MX-COM, Inc.
www.mxcom.com Tel: [phone] 744 5050 Fax: [phone]
Doc. # 20480112.002
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
All trademarks and service marks are held by their respective companies.