CMLMICRO FX469

CML Semiconductor Products
PRODUCT INFORMATION
FX469
1200/2400/4800 Baud
FFSK Modem
Publication D/469/6 April 1998
Features
Pin Selected Xtal/Clock Inputs
1.008MHz or 4.032MHz
Radio and General Applications
Data-Over-Radio
PMR and Cellular Signalling
Portable Data Terminals
Personal/Cordless Telephone
Selectable Data Rates
1200, 2400 and 4800 Baud
Full-Duplex FFSK
Rx and Tx Bandpass Filters
Clock Recovery and Carrier
Detect Facilities
Rx and Tx Enable Functions
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 BAUD SELECT
4800 BAUD SELECT
BANDPASS O/P
Rx ENABLE
Rx FILTER
LIMITER
RETRIGGERABLE
MONOSTABLE
Rx SIGNAL I/P
DATA
FILTER
DIGITAL
FILTER
RECTIFIER
DIGITAL
PLL
DATA
LATCH
LIMITER
UNCLOCKED
DATA O/P
FX469
CLOCKED
DATA O/P
Rx SYNC O/P
NOISE FILTER
RECTIFIER
CARRIER DETECT O/P
S/N
COMPARATOR
CARRIER DETECT TIME CONSTANT
Fig.1 Functional Block Diagram
Brief Description
Rx, Tx and Carrier Detect paths each contain a
bandpass filter to ensure the provision of optimum
signal conditions both in the modem and for the Tx
modulation circuitry.
The FX469 demonstrates a high sensitivity and
good bit-error-rate under adverse signal conditions;
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.
This low-power device requires few external
components and is available in small outline plastic
(S.O.I.C) and cerdip DIL packages.
The FX469 is a single-chip CMOS LSI circuit which
operates as a full-duplex pin-selectable 1200, 2400 or
4800 baud FFSK Modem. The mark and space
frequencies are 1200/1800, 1200/2400 and 2400/4800
Hz respectively. Tone frequencies are phase
continuous; transitions occur at the zero crossing point.
Employing a common Xtal oscillator with a choice of
two clock frequencies (1.008MHz or 4.032MHz) to
provide baud-rate, transmit frequencies, and Rx and Tx
synchronization, the transmitter and receiver operate
entirely independently including individual section
powersave functions.
The FX469 includes on chip circuitry for Carrier Detect
and Rx Clock recovery, both of which are made
available as output pins.
1
Pin Number
Function
FX469
DW LG/LS J/P6
1
1
1
Xtal/Clock : 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 Baud
Selection information on the next page. Operation of any CML microcircuit without a Xtal or
clock input may cause device damage. To minimise damage in the event of a Xtal/drive
failure. it is recommended that the power rail (VDD) is fitted with a current limiting device
(resistor or fast-reaction fuse).
2
2
2
XtalN : Output of the on-chip inverter.
3
3
3
Tx Sync O/P : A squarewave, produced on-chip, to synchronize the input of logic data and
transmission of the FFSK signal (See Figure 4).
4
5
5
Tx Signal O/P : When the transmitter is enabled, this pin outputs the (140-step pseudo
sinewave) FFSK signal (See Figure 4).
With the transmitter disabled, this output is set to a high-impedance state.
5
7
6
Tx Data I/P : Serial logic data to be transmitted is input to this pin.
6
8
7
Tx EnableN : A logic ‘0’ will enable the transmitter (See Figure 4). A logic ‘1’ at this input will
put the transmitter into powersave whilst forcing “Tx Sync Out” to a logic ‘1’ and “Tx Signal
Out” to a high-impedance state. This pin is internally pulled to VDD.
7
9
8
Bandpass O/P : The output of the Rx Bandpass Filter. This output impedance is typically
10kW and may require buffering prior to use.
8
10
9
Rx Enable : The control of the Rx function. The control of other outputs is given below.
Rx Enable
= Rx Function Clock Data O/P
Carrier Detect
Rx Sync Out
“1”
=
Enabled
Enabled
Enabled
Enabled
“0”
=
Powersave
“0”
“0”
1” or “0”
9
11
10
VBIAS: The output of the on-chip analogue bias circuitry. Held internally at VDD/2, this pin
should be decoupled to VSS by a capacitor (C2). (See Figure 2.
This bias voltage is maintained under all powersave conditions.
10
12
11
VSS: Negative supply rail (GND).
2
Pin Number
Function
DW
FX469
LG/LS
J/P6
11
13
12
Unclocked Data O/P: The recovered asynchronous serial data output from the receiver.
12
14
13
Clocked Data O/P: 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 5).
13
15
14
Carrier Detect O/P: When an FFSK signal is being received this output is a logic ‘1.’
14
16
15
Rx Signal I/P: The FFSK signal input for the receiver. This input should be coupled via a
capacitor, C3.
15
18
17
Rx Sync O/P: A flywheel squarewave output. This clock will synchronize to incoming Rx
FFSK data (See Figure 5).
16
19
16
1200/2400 Baud Select: A logic ‘1’ on this pin selects the 1200 baud 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 2400 baud option.
Tone frequencies are: one-half cycle of 1200Hz represents a logic ‘1,’ one cycle of 2400Hz
represents a logic ‘0.’ This function is also used, in part, to select the 4800 baud option. This
pin has an internal 1MW pullup resistor.
Operational Data Rate Configurations are illustrated in the table below.
Xtal/Clock Frequency
Clock Rate pin
1200/2400 Select pin
4800 Select pin
Baud Rate
1.008MHz
0
0
1
0
0
0
1200
2400
1
1
0
1200
4.032MHz
1
1
0
0
0
1
2400
4800
17
20
18
4800 Baud Select: A logic ‘1’ on this pin combined with a logic ‘0’ on the 1200/2400 Baud
Select pin will select the 4800 option (1MW 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.
18
21
19
Clock Rate: 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).
19
22
20
Carrier Detect Time Constant : Part of the carrier detect integration function. The value of
C4 connected to this pin will affect the carrier detect response time and hence noise
performance (See Figure 2, Note 3).
20
24
22
VDD: Positive supply rail. A single 5-volt supply is required.
4, 6, 17,
23
4,
21
No internal connection, do not use.
3
Application Information
VDD
XTAL/CLOCK
R1
X1
XTAL
C1
Tx SYNC O/P
C7
Tx SIGNAL O/P
Tx DATA I/P
BANDPASS O/P
C6
22
2
21
3
20
4
19
5
18
FX469J
6
Tx ENABLE
VDD
1
Rx ENABLE
V BIAS
V SS
17
7
16
8
15
9
14
10
13
11
12
C5
VDD
V SS
C4
CARRIER DETECT
TIME CONSTANT
CLOCK RATE
4800 BAUD SELECT
Rx SYNC O/P
1200/2400 BAUD SELECT
C3
Rx SIGNAL I/P
CARRIER DETECT O/P
CLOCKED DATA O/P
UNCLOCKED DATA O/P
C2
V SS
Component
Value
Tolerance
R1
C1
C2
C3
C4
C5
C6
C7
X1
1.0MW
33.0pF
1.0µF
0.1µF
0.1µF
1.0µF
1.0µF
33.0pF
1.008MHz
or
4.032MHz
±10%
Notes
1. VBIAS may be decoupled to VSS and VDD using C2 and C6
when input signals are referenced to the VBIAS pin. For
input signals referenced to VSS, decouple VBIAS to VSS
using C2 only.
±20%
2. Use C5 when input signals are referenced to VSS, to
decouple VDD.
±10%
±20%
3. 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.
See
‘Clock-Rate’
Pin
4. C7 reduces Xtal voltage overshoot. Refer to CML Xtal
Application Note D/XT/2 December 1991.
Fig.2 External Components
VDD
VDD
MILLIAMMETER
MILLIAMMETER
CLOCKED
DATA O/P
Tx
DATA
I/P
PREAMBLE &
PSEUDO-RANDOM
DATA
GENERATOR
Tx
SIGNAL
O/P
FX469
TRANSMITTER
TELEPHONE
CHANNEL
SIMULATOR
BUFFER
(INTERFACE)
FX469
RECEIVER
(with attenuator
&
5kHz BW noise gen)
CIRCUIT
(components
as Fig. 2)
Rx
SIGNAL
I/P
Rx
SYNC
ERROR
DETECTOR
(components
as Fig. 2)
VSS
Tx SYNC
OSCILLOSCOPE
TRUE RMS
VOLTMETER
TRUE RMS
VOLTMETER
Fig.3 Suggested FX469 Test Set-Up
4
VSS
CARRIER
DETECT
O/P
CARRIER
DETECT
O/P HIGH
DETECTOR
Application Inf
ormation ......
Information
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
1200 BAUD
Tx OUTPUT
2400 BAUD
Tx OUTPUT
OPEN CIRCUIT
OPEN CIRCUIT
OPEN CIRCUIT
OPEN CIRCUIT
Fig.4 Transmitter Timing
Characteristics
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
Undetermined State
Internal Rx Delay
tID
1. Consider the Xtal/Clock tolerance.
2. All Tx timings are related to the Tx Sync Output.
3. 1200 baud example.
Note
Min.
Typ.
Max.
Unit
3
1
2.0
2.0
2.0
800
-
1.2
833
1.5
800
865
2.0
-
µs
µs
µs
µs
µs
µs
µs
ms
3
3
Rx
SIGNAL I/P
2400/4800 BAUD
LOGIC ’0’
LOGIC ’1’
Rx
SIGNAL I/P
1200 BAUD
t ID
1
Rx
SYNC O/P
(1200Hz)
0
Undetermined
State
t RDR
1
CLOCKED
DATA O/P
LOGIC ’1’
0
Fig.5 Rx Timing Diagram
5
LOGIC ’0’
Specification
Absolute Maximum Ratings
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 VSS = 0V)
-0.3 to (VDD + 0.3V)
Sink/source current (supply pins)
+/- 30mA
(other pins)
+/- 20mA
Total device dissipation @ TAMB 25°C
800mW Max.
Derating
10mW/°C
Operating temperature range: FX469DW/LG/LS/P6
FX469J
-30°C to +70°C (plastic)
-30°C to +85°C (cerdip)
Storage temperature range:
-40°C to +85°C (plastic)
-55°C to +125°C (cerdip)
FX469DW/LG/LS/P6
FX469J
Operating Limits
All device characteristics are measured under the following conditions unless otherwise specified:
VDD = 5.0V, TAMB = 25°C. Audio Level 0dB ref: = 300mVrms. Xtal/Clock = 4.032MHz.
Signal-to-Noise Ratio measured in the Bit-Rate Bandwidth Baud Rate = 1200 baud.
Characteristics
Static Values
Supply Voltage
Supply Current Rx Enabled Tx Disabled
Rx and Tx Enabled
Rx and Tx Disabled
Logic ‘1‘ Level
Logic ‘0’ Level
Digital Output Impedance
Analogue and Digital Input Impedance
Tx Output Impedance
On-Chip Xtal Oscillator
RIN
ROUT
Inverter d.c. Voltage Gain
Gain Bandwidth Product
Xtal Frequency
Xtal Frequency
Dynamic Values
Receiver
Signal Input Dynamic Range SNR = 50dB
Bit Error Rate
SNR = 12dB
1200 Baud
2400 Baud
4800 Baud
SNR = 20dB
1200/2400/4800 Baud
See Note
1
1
2
2
3, 4
4
Min.
Typ.
Max.
Unit
4.5
4.0
100
-
5.0
3.6
4.5
650
4.0
0.6
5.5
1.0
1.0
V
mA
mA
µA
V
V
kW
kW
kW
10.0
5.0
10.0
4.1
-
1.008
4.032
15.0
20.0
-
MW
kW
V/V
MHz
MHz
MHz
100
230
1000
mVrms
-
2.5
1.5
1.5
-
104
103
103
-
<1.0
-
108
-
0.995
-
-
-
150
4
Receiver Synchronization SNR =12dB
Probability of Bit 16 Being Correct
7
Carrier Detect
Sensitivity
Probabilty of C.D. Being High
After Bit 16
SNR = 12dB
0dB Noise
No Signal
5, 10
7, 8
5, 9
9
0.995
0.05
6
mVrms
Specification ......
Characteristics
See Note
Min.
Transmitter Output
Tx Output Level
Output Level Variation
1200/1800Hz or 1200/2400Hz or 2400/4800Hz
Output Distortion
3rd Harmonic Distortion
Logic ‘1’ Carrier Frequency
1200 Baud
6
2400 Baud
6
4800 Baud
6
Logic ‘0’ Carrier Frequency
1200 Baud
6
2400 Baud
6
4800 Baud
6
Isochronous Distortion
1200Hz - 1800Hz/1800Hz - 1200Hz
1200Hz - 2400Hz/2400Hz - 1200Hz
2400Hz - 4800Hz/4800Hz - 2400Hz
Typ.
0
-
Max.
Unit
775
-
mVrms
3.0
2.0
1200
1200
2400
1800
2400
4800
±1.0
5.0
3.0
-
dB
%
%
Hz
Hz
Hz
Hz
Hz
Hz
25.0
20.0
-
40.0
30.0
10.0
µs
µs
20 µs
Notes
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
With reference to VDD = 5.0 volts.
Xtal frequency, type and tolerance depends upon system requirements.
See Figure 5 (variation of BER with Input Signal Level).
SNR = Signal-to-Noise Ratio in the Bit-Rate Bandwidth.
See Figure 2.
Dependent upon Xtal tolerance.
10101010101 ...01 pattern.
Measured with a 150mVrms input signal (no noise); 1200/2400 baud operation.
Reference (0dB) level for C.D. probability measurements is 230mVrms.
For 1200 and 2400 baud operation only; when operating at 4800 baud the Carrier Detect output
should be ignored.
1 x 10 -1
*
BIT RATE BANDWIDTH
10
dB
12
dB
SN
R*
SN
R
*
1 x 10 -3
dB
20
BIT ERROR RATE
1 x 10 -2
R
SN
*
1 x 10 -4
1 x 10 -5
50
100
200
150
250
300
500
700
800
INPUT SIGNAL LEVEL (mVrms)
Fig.6 Typical Variation of Bit Error Rate with Input Level
7
Application Information
FX469
IDEAL COHERENT FFSK
2 x 10-2
BIT ERROR RATE (log scale)
10 -2
10 -3
10 -4
8
6
4
2
10
-5
0
2
1
3
4
5
6
7
8
9
10
11
12
13
14
SNR (dB) BIT RATE BANDWIDTH
15
16
(lin scale)
Fig.7 Rx Bit-Error-Rate vs Signal-to-Noise Ratio
Package Outlines
Handling Precautions
The FX469 is available in the package styles outlined
below. Mechanical package diagrams and specifications
are detailed in Section 10 of this document.
Pin 1 identification marking is shown on the relevant
diagram and pins on all package styles number
anti-clockwise when viewed from the top.
The FX469 is a CMOS LSI circuit which includes input
protection. However precautions should be taken to
prevent static discharges which may cause damage.
FX469DW 20-pin plastic S.O.I.C.
FX469J
(D3)
NOT TO SCALE
22-pin cerdip DIL
(J3)
NOT TO SCALE
Max. Body Length
Max. Body Width
12.95mm
7.59mm
Max. Body Length
Max. Body Width
8
27.38mm
9.75mm
Package Outlines ......
FX469LG 24-pin quad plastic encapsulated
bent and cropped
(L1)
FX469LS
NOT TO SCALE
24-lead plastic leaded chip
carrier
(L2)
NOT TO SCALE
Max. Body Length
Max. Body Width
10.25mm
10.25mm
Max. Body Length
Max. Body Width
FX469P6
10.40mm
10.40mm
22-pin plastic DIL
Ordering Information
FX469DW
FX469J
FX469LG
20-pin surface mount S.O.I.C.
22-pin cerdip DIL
24-pin quad plastic encapsulated
bent and cropped
(L1)
FX469LS
24-lead plastic leaded chip carrier
(L2)
FX469P6
22-pin plastic DIL
NOT TO SCALE
Max. Body Length
Max. Body Width
CML does not assume any responsibility for the use of any circuitry described. No circuit patent licences are implied
and CML reserves the right at any time without notice to change the said circuitry.
9
27.94mm
9.14mm
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.
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)/1 February 2002