CMLMICRO MX469

DATA BULLETIN
MX469
1200/2400/4800bps MSK Modem
Features
Applications
Selectable Data Rates
1200/2400/4800bps
Full-Duplex MSK
RX and TX Bandpass Filters
Clock Recovery and
Carrier Detect Capabilities
Pin Selected Xtal/Clock Inputs
1.008MHz or 4.032MHz
TX GENERATOR
Radio and General Applications
Data-Over-Radio
PMR/Cellular Signaling
Portable Data Terminals
Personal/Cordless Telephone
TX FILTER
TX SIGNAL O/P
TX DATA I/P
TX ENABLE
TX SYNC O/P
CLOCK RATE
VDD
XTAL/CLOCK
CLOCK
OSCILLATOR
DIVIDER
f..
V BIAS
n
XTAL
VSS
1200/2400 BPS SELECT
4800 BPS SELECT
BANDPASS O/P
RX ENABLE
RX FILTER
LIMITER
RETRIGGERABLE
MONOSTABLE
RX SIGNAL I/P
DATA
FILTER
LIMITER
UNCLOCKED
DATA O/P
DIGITAL
FILTER
RECTIFIER
DIGITAL
PLL
CLOCKED
DATA O/P
DATA
LATCH
RX SYNC O/P
NOISE FILTER
RECTIFIER
S/N
COMPARATOR
CARRIER DETECT O/P
CARRIER DETECT TIME CONSTANT
The MX469 is a full-duplex pin-selectable 1200/2400/4800bps Minimum Shift Key (MSK) Modem for FM radio
links. The mark and space frequencies are 1200/1800, 1200/2400, and 2400/4800Hz respectively. Tone
frequencies are phase continuous; transitions occur at the zero crossing point. The use of a common Xtal
oscillator with a choice of two clock frequencies (1.008MHz or 4.032MHz) provides data-rate, transmit
frequencies, and RX/TX synchronization. The transmitter and receiver operate entirely independently
including individual section powersave functions.
The MX469 includes on-chip circuitry for Carrier Detect and RX Clock Recovery, both of which are made
available at output pins. RX, TX, and Carrier Detect circuits contain bandpass filters to provide high quality
signals in their respective paths. The carrier detect time constant is set by an external capacitor, whose value
should be arranged as required to further enhance this product's performance in high-noise environments.
The MX469 demonstrates high sensitivity and good bit-error-rate under adverse signal conditions.
This low-power device requires few external components and is available in the following packages:
24-pin SOIC (MX469DW), 22-pin PDIP (MX469P), and 20-pin SOIC (MX469D3).
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
2
MX469
Contents
Section
Page
1. Block Diagram................................................................................................................ 3
2. Signal List....................................................................................................................... 4
3. External Components.................................................................................................... 6
4. General Description....................................................................................................... 7
4.1
Timing.................................................................................................................................. 7
4.1.1 1200bps .................................................................................................................................. 7
4.1.2 2400bps .................................................................................................................................. 8
4.1.3 4800bps .................................................................................................................................. 9
5. Application ................................................................................................................... 10
5.1
Synchronous Modem Design Considerations ................................................................... 10
5.2
Bit Error Rate..................................................................................................................... 11
6. Performance Specifications........................................................................................ 12
6.1
Electrical Specifications..................................................................................................... 12
6.1.1 Absolute Maximum Limits ..................................................................................................... 12
6.1.2 Operating Limits .................................................................................................................... 12
6.1.3 Operating Characteristics...................................................................................................... 13
6.1.4 Packages .............................................................................................................................. 15
MXCOM, Inc. reserves the right to change specifications at any time and without notice.
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
3
MX469
1. Block Diagram
TX GENERATOR
TX FILTER
TX SIGNAL O/P
TX DATA I/P
TX ENABLE
TX SYNC O/P
CLOCK RATE
VDD
XTAL/CLOCK
CLOCK
OSCILLATOR
DIVIDER
f..
V BIAS
n
XTAL
VSS
1200/2400 BPS SELECT
4800 BPS SELECT
BANDPASS O/P
RX ENABLE
RX FILTER
RETRIGGERABLE
MONOSTABLE
LIMITER
RX SIGNAL I/P
DATA
FILTER
LIMITER
DIGITAL
FILTER
RECTIFIER
DIGITAL
PLL
DATA
LATCH
UNCLOCKED
DATA O/P
CLOCKED
DATA O/P
RX SYNC O/P
NOISE FILTER
RECTIFIER
S/N
COMPARATOR
CARRIER DETECT O/P
CARRIER DETECT TIME CONSTANT
Figure 1: Block Diagram
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
4
MX469
2. Signal List
Signal
Type
Description
The input to the on-chip inverter, for use with either a
1.008MHz or a 4.032MHz Xtal or external clock. Clock
frequency selection is by the “Clock Rate” input pin. The
selection of this frequency will affect the operational Data
Rate of this device. Refer to Table 3. Operation of any
MX•COM IC without a Xtal or clock input may cause
device damage. To minimize damage in the event of a
Xtal/drive failure, it is recommended that a current
limiting device (resistor or fast-reaction fuse) be installed
on the power supply (VDD).
P
DW
D3
1
1
1
Xtal/Clock
input
2
2
2
Xtal
output
Output of the on-chip inverter.
3
3
3
TX Sync
output
A squarewave, produced on-chip, to synchronize the
input of logic data and transmission of the MSK signal
(See Figure 3).
5
5
4
TX Signal
output
When the transmitter is enabled, this pin outputs the
(140-step pseudo sinewave) MSK signal (See Figure 3).
With the transmitter disabled, this output is set to a highimpedance state.
6
7
5
TX Data
input
Serial logic data to be transmitted is input to this pin.
7
8
6
TX Enable
Input
A logic ‘0’ will enable the transmitter (See Figure 3). A
logic ‘1’ at this input will put the transmitter into
powersave while forcing “TX Sync Out” to a logic ‘1’ and
“TX Signal Out” to a high-impedance state. This pin is
internally pulled to VDD.
8
9
7
Bandpass
output
The output of the RX Bandpass Filter. This output
impedance is typically 10k and may require buffering
prior to use.
9
10
8
RX Enable
Input
The control of the RX function. The control of other
outputs is provided in Table 2
10
11
9
VBIAS
power
The output of the on-chip analog bias circuitry. Held
internally at VDD/2, this pin should be decoupled to VSS
by a capacitor (C2). See Figure 2 and RX Enable notes.
This bias voltage is maintained under all powersave
conditions.
11
12
10
VSS
power
Negative supply (GND).
12
13
11
Unclocked Data
output
The recovered asynchronous serial data output from the
receiver.
13
14
12
Clocked Data
output
The recovered synchronous serial data output from the
receiver. Data is latched out by the recovered clock,
available at the “RX Sync O/P”. (See Figure 4 and
Figure 6).
14
15
13
Carrier Detect
output
For 1200 and 2400bps operation only. When an MSK
signal is being received this output is a logic ‘1’. The
Carrier Detect signal should be ignored during 4800bps
operation.
15
16
14
RX Signal
input
The MSK signal input for the receiver. This input should
be coupled via a capacitor, C3.
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
5
MX469
Signal
Type
Description
A flywheel squarewave output. This clock will
synchronize to incoming RX MSK data. (See Figure 4
and Figure 6).
P
DW
D3
17
18
15
RX Sync
output
16
19
16
1200/ 2400 BPS
Select
input
A logic ‘1’ on this pin selects the 1200bps option; tone
frequencies are one cycle of 1200Hz represents a logic
‘1’, one-and-a-half cycles of 1800Hz represents a logic
‘0’. A logic ‘0’ on this pin selects the 2400bps option;
tone frequencies are one-half cycle of 1200Hz represents
a logic ‘1’, one cycle of 2400Hz represents a logic ‘0’.
This pin has an internal 1M pull-up resistor.
Operational Data Rate Configurations are illustrated in
Table 3
18
20
17
4800 BPS Select
input
A logic '1' on this pin combined with a logic '0' on the
1200/2400 BPS Select pin will select the 4800 option
(1M pulldown resistor). Tone frequencies are: one-half
cycle of 2400Hz represents a logic '1', one cycle of
4800Hz represents a logic '0'. This state can only be
achieved using a 4.032MHz Xtal input. Operational Data
Rate Configurations are illustrated in Table 3
19
21
18
Clock Rate
input
A logic input to select and allow the use of either a
1.008MHz or 4.032MHz Xtal/clock. Logic ‘1’ =
4.032MHz, logic ‘0’ = 1.008MHz. This input has an
internal pulldown resistor (1.008MHz).
20
23
19
Carrier Detect
Time Constant
output
Part of the carrier detect integration function. The value
of C4 connected to this pin will affect the carrier detect
response time and therefore the noise performance (See
Figure 2, Note 3).
22
24
20
VDD
power
Positive supply. A single 5-volt supply is required.
4,
21
4, 6,
17,
22
N/C
No Internal Connection.
Table 1: Signal List
RX Enable
=
RX Function
Clock Data Output
Carrier Detect
Rx Sync Out
1
=
Enabled
Enable
Enabled
Enabled
0
=
Powersave
0
0
1 or 0
Table 2: RX Enable Control Functions
XTAL/CLOCK Frequency
1.008MHz
4.032MHz
Clock Rate pin
0
0
1
1
1
1200/2400 Select Pin
1
0
1
0
0
4800 Select Pin
0
0
0
0
1
Data Rate (bps)
1200
2400
1200
2400
4800
Table 3: Operational Data Rate Configuration
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
6
MX469
3. External Components
VDD
XTAL/CLOCK
X1
C1
R1
VDD
C7
1
20
XTAL
2
19
TX SYNC OUT
3
18
CLOCK RATE
TX SIGNAL OUT
4
17
4800 BPS SELECT
TX DATA IN
5
16
C6
TX ENABLE
VDD
BANDPASS OUT
C5
RX ENABLE
VBIAS
VSS
6
MX469
CARRIER DETECT TIME CONSTANT
C4
1200/2400 BPS SELECT
15
RX SYNC OUT
RX SIGNAL IN
7
14
8
13
9
12
10
11
C3
CARRIER DETECT OUT
CLOCKED DATA OUT
UNCLOCKED DATA OUT
C2
Figure 2: Recommended External Components
Component
Notes
R1
Value
Tolerance
1.0M
±10%
C1
33pF
±5%
C2
1.0µF
±20%
C3
0.1µF
±20%
C4
Note 1
0.1µF
±10%
C5
Note 2
1.0µF
±25%
C6
Note 3
33pF
±5%
C7
Note 2
1.0µF
±20%
X1
Note 4
1.008MHz or 4.032MHz
See ‘Clock-Rate’ Pin
Table 4: Recommended External Components
Notes:
1. The value of C4 determines the Carrier Detect time constant. A long time constant results in improved
noise immunity but increased response time. C4 may be varied to trade-off response time for noise
immunity.
2. Decoupling circuits depend upon whether the input signal is referenced to VBIAS or VSS. Use C5 when
the input signal is referenced to VBIAS. Use C7 when the input signal is referenced to VSS. It is not
necessary to use both C5 and C7.
3. C6 reduces Xtal voltage overshoot. Reference the MX-COM Xtal Application Note.
4. For best results, a crystal oscillator design should drive the clock inverter input with signal levels of at
least 40% of VDD, peak to peak. Tuning fork crystals generally cannot meet this requirement. To
obtain crystal oscillator design assistance, consult your crystal manufacturer.
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
7
MX469
4. General Description
4.1 Timing
4.1.1 1200bps
Characteristics
Note
TX Enable to TX Sync Rise Time
tSYNC
TX Delay, Signal to Disable Time
tESET
Data Set-Up Time
tDSET
Data Hold Time
tDH
TX Delay to O/P Time
tTXD
TX Data Rate Period
tTDR
RX Data Rate Period
tRDR
Min.
Typ.
Max.
416
µs
2.0
1
800
µs
2.0
µs
2.0
µs
1.2
µs
833
µs
800
Undetermined State
Internal RX Delay
Unit
tID
865
µs
2.0
µs
1.5
ms
Notes:
1. Consider the Xtal/clock tolerance.
2. All TX timings are related to the TX Sync Output.
t SYNC
t ESET
TX
ENABLE
TX
SYNC
t DH
t DSET
TX DATA
DC = Don't Care
DV = Data Valid
DC
DC
DV
t TDR
t TDR
DV
DC
DV
DC
t TXD
OPEN CIRCUIT
OPEN CIRCUIT
1200 BPS
TX OUTPUT
Figure 3: Transmitter Timing: 1200bps
LOGIC '0'
LOGIC '1'
RX
SIGNAL I/P
1200 BPS
t ID
1
RX
SYNC O/P
(1200Hz)
0
t RDR
Undetermined
State
1
CLOCKED
DATA O/P
LOGIC '1'
LOGIC '0'
0
Figure 4: Receiver Timing Diagram: 1200bps
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
8
MX469
4.1.2 2400bps
Characteristics
Note
TX Enable to TX Sync Rise Time
tSYNC
TX Delay, Signal to Disable Time
tESET
Data Set-Up Time
tDSET
Min.
Typ.
Max.
208
µs
2.0
1
Unit
400
2.0
µs
µs
Data Hold Time
tDH
TX Delay to O/P Time
tTxD
2.0
1.2
µs
µs
TX Data Rate Period
tTDR
416
µs
RX Data Rate Period
tRDR
400
Undetermined State
Internal RX Delay
tID
433
µs
2.0
µs
1.5
ms
Notes:
1. Consider the Xtal/Clock tolerance.
2. All TX timings are related to the TX Sync Output.
t SYNC
t ESET
TX
ENABLE
TX
SYNC
t DH
t DSET
TX DATA
DC = Don't Care
DV = Data Valid
DC
DV
DC
DV
t TDR
DC
DV
DC
DV
DC
t TDR
DV
DC
DV
DC
t TXD
2400 BPS
TX OUTPUT
OPEN CIRCUIT
OPEN CIRCUIT
Figure 5: Transmitter Timing: 2400bps
LOGIC '1'
LOGIC '0'
LOGIC '1'
LOGIC '0'
RX
SIGNAL I/P
2400 BPS
t ID
1
RX
SYNC O/P
(2400Hz)
0
Undetermined
State
t RDR
1
CLOCKED
DATA O/P
LOGIC '1'
LOGIC '0'
LOGIC '1'
LOGIC '0'
0
Figure 6: Receiver Timing: 2400bps
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
9
MX469
4.1.3 4800bps
Characteristics
Note
TX Enable to TX Sync Rise Time
tSYNC
TX Delay, Signal to Disable Time
tESET
Data Set-Up Time
tDSET
Min.
Typ.
Max.
Unit
104
µs
2.0
1
200
µs
2.0
µs
Data Hold Time
tDH
TX Delay to O/P Time
tTxD
2.0
1.2
µs
µs
TX Data Rate Period
tTDR
208
µs
RX Data Rate Period
tRDR
200
Undetermined State
Internal RX Delay
tID
216
µs
2.0
µs
1.0
ms
Notes:
1. Consider the Xtal/Clock tolerance.
2. All TX timings are related to the TX Sync Output.
t SYNC
t ESET
TX
ENABLE
TX
SYNC
t DH
t DSET
TX DATA
DC = Don't Care
DV = Data Valid
DC
DV
DC
DV
t TDR
DC
DV
DC
DV
DC
t TDR
DV
DC
DV
DC
t TXD
4800 BPS
TX OUTPUT
OPEN CIRCUIT
OPEN CIRCUIT
Figure 7: Transmitter Timing: 4800bps
LOGIC '1'
LOGIC '0'
LOGIC '1'
LOGIC '0'
RX
SIGNAL I/P
4800 BPS
t ID
1
RX
SYNC O/P
(4800Hz)
0
Undetermined
State
t RDR
1
CLOCKED
DATA O/P
LOGIC '1'
LOGIC '0'
LOGIC '1'
LOGIC '0'
0
Figure 8: Receiver Timing: 4800bps
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
10
MX469
5. Application
5.1 Synchronous Modem Design Considerations
The MX469 is an easily applied data pump, which can be used with many protocols. Because it is an MSK, or
minimum shift keying, modem, it achieves a more noise resistant, higher data rate in a narrower bandwidth
than other FSK (frequency shift keying) modems. This characteristic is especially important for wireless
applications because it fundamentally determines the bandwidth of RF transmissions, which are strictly limited
and controlled by regulatory agencies. Using MSK signaling, the MX469 data modem can achieve a 2400bps
data rate within the typical 300-3000 Hz voice band of many common radios.
In order to achieve this advantage, an MSK modem must precisely control the bit rate and timing of the
modulated Tx output signal bits. This control is asserted by the MSK modem with a data clock signal, which
is output, by the modem to pace the Tx data source (e.g. a microcontroller). The data clock signal, in effect,
indicates when the Tx data source should provide the next Tx data bit to the modem. See Figure 9. Because
this type of interface involves the use of a modem generated bit clock signal to control the timing of when new
Tx data bits must be supplied from the data source, the interface is called synchronous.
Another characteristic of a synchronous modem is that, to receive data, it must first learn the data bit timing of
the Rx signal stream before it can accurately demodulate Rx data bits. Accordingly, a synchronous modem
undergoes a period of training or synchronization when it first begins to receive a stream of MSK modulated
signal. During this initial receive phase, the received signal is evaluated over several bit times as the modem
‘locks on’ and achieves proper receive synchronization. The training sequence, called a preamble, is a
specific data pattern which must be added to the ‘front’ of a transmit data stream with the start of each new
transmission. A specific preamble data pattern (e.g. 16 bits of alternating 0,1,0,1… for the MX469) is used to
optimize the training accuracy while minimizing the number of preamble bits required.
Tx data
DATA: 0 1 1
0
1
1
Data Bit Tx
Source
(e.g. µC)
MSK Modem
Transmitting
I took BIT 3
Give me BIT 3
I took BIT 2
Give me BIT 2
I took BIT 1
Give me BIT 1
Tx SYNC
(data clock)
MSK Tx Out
Figure 9: Synchronous Transmit Operation
Non-synchronous or asynchronous interfaces are commonly found in wired applications which do not have
the bandwidth efficiency requirements of wireless systems. A well known example is the serial port of a
personal computer which can transmit a 1200 bps (or faster) data signal over a single Tx signal without using
an additional data clock signal to control the precise rate and timing of data bits being transmitted to a typical
telephone line data modem. Popular modem standards such as Bell 202 and v.23 use FSK signaling to pass
such asynchronous serial port data signals over telephone systems.
Another aspect of asynchronous interfaces and modems is that they can carry data streams which are not at
the exact, nominal data rate. For example, a 1200 bps FSK modem will typically operate properly when
supplied with transmit data streams of 1201 bps or 1199 bps.
Because of the differences in synchronous and asynchronous interfaces, they cannot successfully operate if
directly connected. In other words, a personal computer’s RS232 serial port cannot directly interface to an
MSK modem. This is because:
The asynchronous interface may provide data bits too fast or too slow compared to the precise rate
required for MSK signaling (a bit rate, or pacing, incompatibility).
The timing of each specific data bit presented by an asynchronous interface will not be aligned with the
precise bit timing required for MSK signaling (a bit timing incompatibility).
Synchronous and asynchronous interface can be successfully interfaced for applications requiring the
advantages of both. This typically involves the use of data buffering and retiming circuits to resolve the timing
and pacing issues.
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
11
MX469
5.2 Bit Error Rate
VDD
VDD
MILLIAMMETER
MILLIAMMETER
CLOCKED
DATA OUT
TX
DATA
I/P
PREAMBLE &
PSEUDO-RANDOM
DATA
GENERATOR
TX
SIGNAL
O/P
MX469
TRANSMITTER
BUFFER
(INTERFACE)
CIRCUIT
(components
as Fig. 2)
RX
SIGNAL
IN
S3 TELEPHONE
CHANNEL
SIMULATOR
RX
SYNC
MX469
RECEIVER
(with attenuator
&
5kHz BW noise gen)
ERROR
DETECTOR
(components
as Fig. 2)
Tx SYNC
OSCILLOSCOPE
TRUE RMS
VOLTMETER
TRUE RMS
VOLTMETER
CARRIER
DETECT
OUT
CARRIER
DETECT
OUT HIGH
DETECTOR
Figure 10: MX469 Test Set-Up
Figure 11: Typical Variation of Bit Error Rate with Input Level
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
12
MX469
IDEAL COHERENT MSK
2 x 10-2
MX469
BIT ERROR RATE (log scale)
10 -2
10 -3
10 -4
8
6
4
2
10 -5
0
1
2
3
4
5
7
6
8
9
10
11
13
12
14
15
16
SNR (dB) BIT RATE BANDWIDTH (lin scale)
Figure 12: RX Bit-Error-Rate vs. Signal-to-Noise Ratio
6. Performance Specifications
6.1 Electrical Specifications
6.1.1 Absolute Maximum Limits
Exceeding these maximum ratings can result in damage to the device.
General
Notes
Min.
Typ.
Max.
Units
Supply (VDD-VSS)
-0.3
7.0
V
Voltage on any pin to VSS
-0.3
VDD + 0.3
V
VDD
-30
30
mA
VSS
-30
30
mA
Any other pin
-20
20
mA
Current
DW / D3 / P Packages
10
Derating above 25C
mW/C above 25C
Operating Temperature
-40
85
C
Storage Temperature
-55
125
C
6.1.2 Operating Limits
Correct Operation of the device outside these limits is not implied.
Notes
Min.
Typ.
Max.
Units
Supply (VDD-VSS)
4.5
5.0
5.5
V
Operating Temperature
-40
85
C
1.008
4.032
MHz
Xtal Frequency
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
13
MX469
6.1.3 Operating Characteristics
For the following conditions unless otherwise specified.
VDD = 5.0V @ TAMB = 25C
Audio Level 0dB ref. = 300mVRMS, Xtal/Clock Frequency = 4.032MHz
Signal-to-Noise Ratio measured in the Bit-Rate Bandwidth
1200bps BRB = 1200Hz
2400bps BRB = 2400Hz
4800bps BRB = 4800Hz
Notes
Min.
Typ.
Max.
Units
Static Values
Supply Current
RX Enabled, TX Disabled
3.6
mA
RX and TX Enabled
4.5
mA
RX and TX Disabled
650
µA
Logic ‘1‘ Level
1
Logic ‘0’ Level
1
4.0
V
1.0
Digital Output Impedance
4.0
Analog and Digital Input Impedance
k
100
TX Output Impedance
V
k
0.6
1.0
k
On-Chip Xtal Oscillator
RIN
10.0
ROUT
M
10.0
k
Inverter DC Voltage Gain
10.0
V/V
Gain Bandwidth Product
10.0
MHz
Dynamic Values
Receiver
Signal Input Dynamic Range
SNR = 50dB
3, 4
100
230
1000
mVRMS
Bit Error Rate
7.0
10-4
1200bps
2.5
10-4
2400bps
1.5
10-3
4800bps
1.5
10-3
1.0
10-8
Probability of Bit 8 Being Correct
99
%
Probability of Bit 16 Being Correct
99.5
%
SNR = 12dB
4
SNR = 20dB
4
1200/2400/4800bps
Receiver Synchronization
SNR =12dB
7
5, 10
Carrier Detect
Sensitivity
7, 8
150
mVRMS
Probability of C.D. Being High
After Bit 8
(1200bps) SNR = 12dB
5, 9
98
%
SNR = 12dB
5, 9
99.5
%
9
5
%
After Bit 16
0dB Noise
1998 MX-COM, Inc.
No Signal
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
14
MX469
Notes
Min.
Typ.
Max.
Units
Transmitter Output
TX Output Level
775
mVRMS
Output Level Variation
1200/1800Hz
0
±1.0
dB
1200/2400Hz
0
±1.0
dB
2400/4800Hz
0
±1.0
dB
Output Distortion
3.0
5.0
%
3rd Harmonic Distortion
2.0
3.0
%
Logic ‘1’ Carrier Frequency
1200bps
6
1200
Hz
2400bps
6
1200
Hz
4800bps
6
2400
Hz
1200bps
6
1800
Hz
2400bps
6
2400
Hz
4800bps
6
4800
Hz
Logic ‘0’ Carrier Frequency
Isochronous Distortion
1200Hz - 1800Hz/1200Hz 2400Hz
25.0
40.0
s
1800Hz - 1200Hz/2400Hz 1200Hz
20.0
40.0
s
2400Hz - 4800Hz/4800Hz 2400Hz
10.0
20.0
s
Operating Characteristics Notes:
1. With reference to VDD = 5.0 volts.
2. Xtal frequency (ref. Clock Rate pin), type and tolerance depends upon system requirements.
3. See Figure 4 (variation of BER with Input Signal Level).
4. SNR = Signal-to-Noise in the Bit-Rate Bandwidth.
5. See Figure 2.
6. Dependent upon Xtal tolerance.
7. 10101010101 ...01 pattern.
8. Measured with a 150mVRMS input signal (no noise).
9. Reference (0dB) level for C.D. probability measurements is 230mVRMS.
10. For 1200bps and 2400bps operation only: when operating at 4800bps the carrier detect output should
be ignored.
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
15
MX469
6.1.4 Packages
Figure 13: 24-pin SOIC Mechanical Outline: Order as part no. MX469DW
Package Tolerances
A
B
E1
E
Y
T
PIN 1
K
C
H
L
J1
J
P
DIM.
A
B
C
E
E1
H
J
J1
K
L
P
T
Y
MIN.
TYP.
MAX.
1.100 (27.94)
0.360 (9.14)
1.080 (27.43)
0.330 (8.38)
0.185 (4.70)
0.420 (10.67)
0.480 (12.19)
0.390 (9.91)
0.420 (10.67)
0.020 (0.51)
0.045 (1.14)
0.015 (0.38)
0.020 (0.51)
0.065 (1.65)
0.040 (1.02)
0.066 (1.68)
0.128 (3.25)
0.100 (2.54)
0.010 (0.25)
7°
NOTE : All dimensions in inches (mm.)
Angles are in degrees
Figure 14: 22-pin PDIP Mechanical Outline: Order as part no. MX469P
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
1200/2400/4800bps MSK Modem
16
MX469
Package Tolerances
A
Z
B
ALTERNATIVE
PIN
LOCATION
MARKING
E
W
L
T
PIN 1
X
Y
C
J
H
K
P
DIM.
MIN.
TYP.
MAX.
A
B
C
E
H
J
K
L
P
T
W
X
Y
Z
0.510 (12.95)
0.495 (12.57)
0.299 (7.59)
0.286 (7.26)
0.093 (2.36)
0.105 (2.67)
0.419 (10.64)
0.390 (9.90)
0.003 (0.08)
0.020 (0.51)
0.013 (0.33)
0.020 (0.51)
0.046 (1.17)
0.036 (0.91)
0.050 (1.27)
0.016 (0.41)
0.050 (1.27)
0.009 (0.23)
0.0125 (0.32)
45°
0°
10°
5°
7°
5°
NOTE : All dimensions in inches (mm.)
Angles are in degrees
Figure 15: 20-pin SOIC Mechanical Outline: Order as part no. MX469D3
1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
Doc. # 20480081.010
All trademarks and service marks are held by their respective companies.
CML Microcircuits
COMMUNICATION SEMICONDUCTORS
CML Product Data
In the process of creating a more global image, the three standard product semiconductor
companies of CML Microsystems Plc (Consumer Microcircuits Limited (UK), MX-COM, Inc
(USA) and CML Microcircuits (Singapore) Pte Ltd) have undergone name changes and, whilst
maintaining their separate new names (CML Microcircuits (UK) Ltd, CML Microcircuits (USA)
Inc and CML Microcircuits (Singapore) Pte Ltd), now operate under the single title CML
Microcircuits.
These companies are all 100% owned operating companies of the CML Microsystems Plc
Group and these changes are purely changes of name and do not change any underlying legal
entities and hence will have no effect on any agreements or contacts currently in force.
CML Microcircuits Product Prefix Codes
Until the latter part of 1996, the differentiator between products manufactured and sold from
MXCOM, Inc. and Consumer Microcircuits Limited were denoted by the prefixes MX and FX
respectively. These products use the same silicon etc. and today still carry the same prefixes.
In the latter part of 1996, both companies adopted the common prefix: CMX.
This notification is relevant product information to which it is attached.
CML Microcircuits (USA) [formerly MX-COM, Inc.] Product Textual Marking
On CML Microcircuits (USA) products, the ‘MX-COM’ textual logo is being replaced by a ‘CML’
textual logo.
Company contact information is as below:
CML Microcircuits
(UK)Ltd
CML Microcircuits
(USA) Inc.
CML Microcircuits
(Singapore)PteLtd
COMMUNICATION SEMICONDUCTORS
COMMUNICATION SEMICONDUCTORS
COMMUNICATION SEMICONDUCTORS
Oval Park, Langford, Maldon,
Essex, CM9 6WG, England
Tel: +44 (0)1621 875500
Fax: +44 (0)1621 875600
uk.sales@cmlmicro.com
www.cmlmicro.com
4800 Bethania Station Road,
Winston-Salem, NC 27105, USA
Tel: +1 336 744 5050,
0800 638 5577
Fax: +1 336 744 5054
us.sales@cmlmicro.com
www.cmlmicro.com
No 2 Kallang Pudding Road, 09-05/
06 Mactech Industrial Building,
Singapore 349307
Tel: +65 7450426
Fax: +65 7452917
sg.sales@cmlmicro.com
www.cmlmicro.com
D/CML (D)/2 May 2002