CMLMICRO FX128

CML Semiconductor Products
Cordless Telephone Scrambler
D/128/1 October 1997
FX128
Provisional Information
Features
•
Full-Duplex Audio Processing
•
Excellent Audio Quality
•
On-Chip Filters
•
Low Power Operation (3.0V)
•
Carrier Rejection >55dB
•
ECPA* Qualified Voice Protection
•
Uses IF (10.24MHz) Clock
•
Battery Powered Portability
•
Requires No Extra Crystal
•
Cordless Telephones and Wireless PBX
Applications
1.1
Brief Description
The FX128 is a full-duplex frequency inversion scrambler designed to provide secure conversations for
46/49 MHz cordless telephone users. The Rx and Tx audio paths consist of the following:
1.
2.
3.
4.
A switched-capacitor balanced modulator with high baseband and carrier rejection.
A 3.3kHz inversion carrier (injection tone).
A 3100Hz lowpass filter.
Input op-amps with externally adjustable gain.
The FX128 uses mixed signal CMOS switched-capacitor filter technology and operates from a single supply in
the range of 3.0 to 5.5 volts. The inversion carrier's frequency and filter switching clock are generated on-chip
using an external 10.24MHz or 3.58/3.6864 MHz crystal or clock input (selectable).
This device is available in 16-pin SOIC (FX128D4) and 16-pin plastic DIL (FX128P3) packages.
*Electronics Communications Privacy Act (Title 18, US Code 2510 etc.).
1
Cordless Telephone Scrambler
FX128
CONTENTS
Section
Page
1.1 Brief Description........................................................................................ 1
1.2 Block Diagram........................................................................................... 3
1.3 Signal List ................................................................................................. 4
1.4 External Components ................................................................................ 5
1.5 Application .............................................................................................. 6
1.6 Application Notes .................................................................................... 6
1.7 Performance Specification....................................................................... 7
1.7.1 Electrical Performance ............................................................. 7
1.7.2 Packaging................................................................................ 10
2
Cordless Telephone Scrambler
1.2
FX128
Block Diagram
RX GAIN AMP OUT
Rx CHANNEL
+
RXIN
RXOUT
VBIAS
CLR
XTAL/CLOCK
10.24/3.58 MHz
3.3kHz
CLOCKS
AND
LOGIC
XTALN
CLOCK SELECT
VDD
VDD
2
212kHz
0V
VBIAS
VSS
VBIAS
TXIN
TX GAIN AMP OUT
+
-
TXOUT
Tx CHANNEL
Figure 1 Block Diagram
3
Cordless Telephone Scrambler
1.3
FX128
Signal List
Package
D4/P3
Signal
Description
Pin No.
Name
Type
1
XTALN
O/P
This is the output of the clock oscillator inverter.
2
XTAL/CLOCK
I/P
10.24MHz or 3.58/3.6864 MHz or an externally derived
clock is injected at this pin. See Figure 2.
3
-
N/C
No connection should be made to this pin.
4
TXOUT
O/P
This is the analogue output of the transmit channel. It
is internally biased at VDD/2.
5
TX GAIN AMP
OUT
O/P
This is the output pin of the transmit gain adjusting opamp. See Figure 3 for gain setting components.
6
TXIN
I/P
This is the analogue signal input to the transmit
channel. This input goes to a gain adjusting op-amp
whose gain is set by external components.
See Figure 3.
7
-
N/C
No connection should be made to this pin.
8
VSS
POWER
9
VBIAS
O/P
This is an internally generated bias voltage output
(VDD/2)
10
-
N/C
No connection should be made to this pin.
11
RXIN
I/P
This is the analogue signal input to the receive
channel. This input goes to a gain adjusting op-amp
whose gain is set by external components.
See Figure 3.
12
RX GAIN AMP
OUT
O/P
This is the output pin of the receive gain adjusting opamp. See Figure 3 for gain setting components.
13
RXOUT
O/P
This is the analogue output of the receive channel. It
is internally biased at VDD/2.
14
CLR
I/P
A logic 1 on this input selects the invert mode. A logic
0 selects the clear (not inverted) mode.
15
CLOCK
SELECT
I/P
Selects either 10.24 or 3.58/3.6864 MHz clock
frequency. A logic “1” selects 10.24MHz and a logic
“0” selects 3.58/3.6864 MHz. This input is internally
pulled high.
16
VDD
POWER
Notes:
I/P
O/P
N/C
=
=
=
Negative supply (GND)
Positive supply of 3.0 to 5.5V.
Input
Output
No Connection
4
Cordless Telephone Scrambler
1.4
FX128
External Components
Component
X1
R1
C1
C2
C3
Tolerance:
Value
10.24MHz
Value
3.58/3.6864 MHz
1.0MΩ
0.47µF
22.0pF
22.0pF
1.0MΩ
0.47µF
33.0pF
47.0pF
R = ±10%
C = ±20%
Note: Xtal circuitry shown is in accordance with CML’s Xtal Application Note.
Figure 2 Recommended External Components
5
Cordless Telephone Scrambler
1.5
FX128
Application
BASE
IF
AMP
RF
AMP
FM
DETECTOR
120pF
RXIN
RXOUT
12
.1uF
13
100k
11
100k
RF AMP
150pF
FX128
DTMF
Generation
CODE
ENCODE
MODULATOR
AF AMP
.1uF
CODE
DETECT
µP
DE-EMP
100k
120pF
PREEMP
5
100k 100k
4
6
100k .1uF
150pF
HYBRID
TRANSFORMER
TELEPHONE
LINE
AF
AMP
.1uF
TXOUT
TXIN
PORTABLE
IF
AMP
RF
AMP
FM
DETECTOR
120pF
RXIN
RXOUT
12
.1uF
11
100k
100k
13
100k
RF AMP
MODULATOR
150pF
FX128
P
CODE
ENCODE
150pF
SPKR
.1uF
CODE
DETECT
KEYPAD
DE-EMP AF AMP
120pF
PREEMP
5
.1uF
AF
AMP
MIC.
100k 100k
4
6
100k
TXOUT
.1uF
TXIN
Note: Components shown set a gain of 0dB
Figure 3 Block Diagram of a Typical Application of the FX128 (Cordless Phone)
1.6
Application Notes
Formulae for calculating the carrier frequency, upper cutoff frequency and lower cutoff frequency with clock
select pin high are as follows:
Carrier Frequency
Upper Cutoff Frequency
Lower Cutoff Frequency
=
=
=
(3.2995kHz / 10.24MHz) * XTAL frequency
(2.800kHz / 10.24MHz) * XTAL frequency
(400Hz / 10.24MHz) * XTAL frequency
Formulae for calculating the carrier frequency, upper cutoff frequency and lower cutoff frequency with clock
select pin low are as follows:
Carrier Frequency
Upper Cutoff Frequency
Lower Cutoff Frequency
=
=
=
(3.2995kHz / 3.415MHz) * XTAL frequency
(2.800kHz / 3.415MHz) * XTAL frequency
(400Hz / 3.415MHz) * XTAL frequency
6
Cordless Telephone Scrambler
1.7
Performance Specification
1.7.1
Electrical Performance
FX128
Absolute Maximum Ratings
Exceeding these maximum ratings can result in damage to the device.
General
Supply (VDD - VSS)
Voltage on any pin to VSS
Current in or out of VDD and VSS pins
Current in or out of any other pin
D4 and P3 Packages
Total Device Dissipation at Tamb = 25°C
. . . Derating
Storage Temperature
Operating Temperature
Min
- 0.3
-0.3
-30
-20
Max
7.0
(VDD + 0.3)
+30
+20
Units
V
V
mA
mA
-55
-40
800
10
+125
+85
mW
mW/°C
°C
°C
Operating Limits
Correct operation of the device outside these limits is not implied.
Min.
3.0
-40
Supply (VDD - VSS)
Operating Temperature
Clock Frequency
7
Max.
5.5
+85
10.24
Units
V
°C
MHz
Cordless Telephone Scrambler
FX128
Operating Characteristics
For the following conditions unless otherwise specified:
VDD = 3.3V at Tamb = 25°C
Clock Frequency = 10.24MHz
Audio Level 0dB ref. at 1kHz = (VDD - 1) x 150vrms e.g. VDD = 3.3V 0dB = 345mVrms
Notes
Min.
Typ.
Max.
Units
-
2.0
3.0
mA
100
1.0
10.0
-
kΩ
MΩ
-
1.0
-
kΩ
1
1
70%
-
-
30%
VDD
VDD
4
-16.0
-
2.5
3
5.0
dB
mVrms
3000
-
300
-
Hz
Hz
Passband Ripple (300-3000Hz)
Rx Channel
Tx Channel
0
0
-
3.6
2.9
dB
dB
Passband Ripple (500-2750Hz)
Rx Channel
Tx Channel
0
0
-
2.2
2.0
dB
dB
Filter Attenuation at 3.3kHz
Rx and Tx Channel
-
30
-
dB
Filter Attenuation at 3.6kHz
Rx and Tx Channel
-
45
-
dB
-1.5
-
0.5
dB
-
211.066
3298
-
kHz
Hz
Static Values
Supply Current
Input Impedance
Digital
Amplifiers
2
2
Output Impedance (RXOUT, TXOUT)
Input Logic ‘1’ Voltage
Input Logic ‘0’ Voltage
Dynamic Values
General
Analog Signal Input Levels
Analog Output Noise
Clear Mode
Passband -3dB Cutoff Frequencies
Low
High
Passband Gain (@ 1kHz ref.)
Rx and Tx Channel
Switched-Capacitor Filter Sampling
Carrier Frequency
8
Cordless Telephone Scrambler
FX128
Notes
Invert Mode Combined Tx and Rx Response
Passband -3dB Cutoff Frequencies
Low
High
Passband Gain
Distortion (@ 1kHz)
Passband Gain (@ 1kHz ref.)
Low Frequency Roll-off (<200Hz)
3
5
Invert Mode Single Channel Response
Unwanted Modulation Products
Rx and Tx Channel
3
Carrier Breakthrough
Rx and Tx Channel
3
Baseband Breakthrough
Rx and Tx Channel
3
Min.
Typ.
Max.
Units
2800
-
400
-
Hz
Hz
-3
-2.5
12
1.75
-1.5
-
0.5
2.75
0
-
dB
%
dB
dB/oct.
-
-40
-
dB
-
-55
-
dB
-
-40
-
dB
Operating Characteristics Notes:
1.
2.
3.
4.
5.
6.
Batch sampled only.
By characterisation only.
Measured with Input Level 0dB.
Short circuit Rx or Tx input, measure noise at corresponding analogue output, in 30kHz bandwidth.
Op Amp gain 0dB.
Clear mode only.
9
1.7.2 Package Outlines
Handling Precautions
The FX128 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 FX128 is a CMOS LSI circuit which includes input
protection. However precautions should be taken to
prevent static discharges which may cause damage.
FX128D4 16-pin Plastic S.O.I.C.
FX128P3
(DW)
NOT TO SCALE
16-pin Plastic DIL
(P)
NOT TO SCALE
Max. Body Length
Max. Body Width
10.49mm
7.59mm
Max. Body Length
Max. Body Width
Ordering Information
FX128D4
16-pin Plastic S.O.I.C.
FX128P3
16-pin Plastic DIL
(DW)
(P)
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.
10
20.57mm
6.60mm
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