CMX990
CML Microcircuits
COMMUNICATION SEMICONDUCTORS
D/990/1 April 2004
GMSK Packet Data Modem
and RF Transceiver
Advance Information
Features
•
Single Chip RF Transceiver and GMSK Modem
•
IF, RF, Control and Synthesizer Stages
•
Selectable B
t
= 0.3 or 0.5
•
Full Mobitex Compatibility
•
Packet and Freeformat (Raw) Data
•
Versatile Data Rates: 4kbps to 16kbps
•
Simple Parallel Interfacing
•
Low-Power, Low Profile, Low-Cost BOM
•
Flexible System Clocks
Applications
•
Narrowband Data Over Radio
•
Mobitex Data Terminals
•
400MHz to 1GHz Radio Data Systems
•
Radio Modems
•
Wireless Telemetry
•
SCADA Terminals
•
Suitable for EN 300 113 and FCC
CFR 47 Part 90 Applications
1.
Brief Description
A single-chip GMSK packet-data modem and RF transceiver, the CMX990 provides the majority of
circuits and functions, including host µC interfaces, to implement a full-feature ‘wireless modem’
subsystem. The CMX990 can operate in RF ranges of 400MHz to 1GHz at data rates of 4 to 16 kbps
and is fully Mobitex compatible.
©
2004 CML Microsystems Plc
GMSK Packet Data Modem and RF Transceiver
CMX990
With a minimum of external components and circuits, this half-duplex device provides on-chip: a flexible,
formattable GMSK packet and freeformat modem, a dual operation synthesiser fed from an external
source, IF and RF stages for both Rx and Tx modes, and auxiliary ADCs and DACs for system control
and monitoring.
This versatile GMSK modem is programmable to both packet and freeformat data operations via an
efficient task-oriented Rx and Tx format and command structure, which is combined with data
scrambling, interleaving and FEC and CRC capabilities. Rx data acquisition, extraction and tracking
abilities, allied with Rx data quality feedback, allow the CMX990 to operate seamlessly in varying signal
environments.
IF and RF functions in the Tx path handle all the required signal mixing and up-conversion to produce
the FM modulation for the final external PA circuitry. In the Rx path these circuits provide initial
selectivity and rejection characteristics and mix down the inputs to provide baseband signals for the
modem.
Comprehensive internal and external system control and monitoring is provided by the 8-bit host
interface registers and the on-chip ADCs and DACs. Requiring a power supply input in the range 3.0 to
3.6 Volts, the CMX990 can be used in wireless products designed to comply with such standards as EN
300 113 and FCC CFR 47 Part 90. Operating over a temperature range of -40°C to +85°C, the CMX990
consolidates the core radio modem functions to enable a new generation of small, narrow-band wireless
data modems. The CMX990 comes in a 64-pin low profile VQFN package.
©
2004 CML Microsystems Plc
2
D/990/1
GMSK Packet Data Modem and RF Transceiver
CMX990
CONTENTS
Section
1.
2.
3.
4.
Page
Brief Description.................................................................................. 1
Block Diagram ..................................................................................... 4
Signal List ............................................................................................ 5
External Components.......................................................................... 8
4.1
Processor Interface................................................................. 9
4.2
Synthesiser and TCXO ......................................................... 10
4.3
Transmit ................................................................................ 11
4.4
Receive .................................................................................. 12
4.5
Power Supply Decoupling and Layout ................................ 13
General Description........................................................................... 15
5.1
Baseband Modem ................................................................. 15
5.1.1 Description of Blocks............................................... 15
5.1.2 Modem - µC Interaction ............................................ 17
5.1.3 Data Formats............................................................. 18
5.1.4 Programmer’s View of the Modem .......................... 20
5.1.5 CRC, FEC, Interleaving and Scrambling Details..... 37
5.1.6 Application Notes ..................................................... 40
5.2
µC Interface ........................................................................... 44
5.2.1 Memory Map and Interface....................................... 44
5.2.2 Power-on and Reset ................................................. 45
5.2.3 Clock Control............................................................ 46
5.2.4 Status Registers ....................................................... 47
5.2.5 Write Only Registers ................................................ 48
5.2.6 Read Only Registers................................................. 52
5.3
Auxiliary DAC and ADC......................................................... 54
5.4
Synthesiser............................................................................ 57
5.5
RF and IF ............................................................................... 59
5.5.1 Receiver Section....................................................... 59
5.5.2 Transmitter Section.................................................. 60
5.5.3 Alternative Receiver Architecture ............................ 60
Application Notes .............................................................................. 62
6.1
General .................................................................................. 62
6.2
Transmitter ............................................................................ 62
6.3
Receiver................................................................................. 64
6.4
Variable Bt ............................................................................. 69
Performance Specification................................................................ 71
7.1
Electrical Performance.......................................................... 71
7.2
Packaging.............................................................................. 77
It is always recommended that you check for the latest product datasheet version from the
Datasheets page of the CML website: [www.cmlmicro.com].
Note:
This product is in development: Changes and additions will be made to this specification.
Items marked TBD or left blank will be included in later issues.
5
6.
7.
Information in this data sheet should not be relied upon for final product design.
©
2004 CML Microsystems Plc
3
D/990/1
GMSK Packet Data Modem and RF Transceiver
CMX990
2.
Block Diagram
Figure 1 Block Diagram
©
2004 CML Microsystems Plc
4
D/990/1
GMSK Packet Data Modem and RF Transceiver
CMX990
3.
Signal List
Signal
Name
PA-CNTL
TX FB
TXIF2
TXIF1
TXPLL
RF IN A
RF IN B
IF OUT
LNA ON
IF IN
DAC3
DAC2
ADC5
ADC4
OP2T
OP2N
OP2P
OP1T
OP1N
OP1P
REFCLK
TCXO-CNTL
TCXO-TEMP
LOCLKN
LOCLK
MAINPLL
AUXPLL
IFCLK
PA-TEMP
Type
O/P
I/P
BI
BI
O/P
I/P
I/P
O/P
O/P
I/P
O/P
O/P
I/P
I/P
O/P
I/P
I/P
O/P
I/P
I/P
I/P
O/P
I/P
I/P
I/P
O/P
O/P
I/P
I/P
DAC0 output to control PA power.
Tx feedback input signal.
Offset loop filter connection.
Offset loop filter connection.
Tx Phase Detector output.
RF input A for received signal.
RF input B for received signal.
Output to the external IF filter.
Digital output to turn on external LNA block.
Input from the external IF filter.
Spare D/A output.
Spare D/A output.
Spare A/D input.
Spare A/D input.
Uncommitted op-amp 2 output, internally
connected to ADC3.
Uncommitted op-amp 2 negative input.
Uncommitted op-amp 2 positive input.
Uncommitted op-amp 1 output, internally
connected to ADC2.
Uncommitted op-amp 1 negative input.
Uncommitted op-amp 1 positive input.
Master clock input from external TCXO.
DAC1 output to control TCXO.
A/D input to measure TCXO temperature,
internally connected to ADC1.
Inverted input from the RF Oscillator circuit.
Input from the RF Oscillator circuit.
Main PLL output, connect to external filter.
Aux PLL output, connect to external filter.
Input from the IF Oscillator circuit.
A/D input to measure PA temperature, internally
connected to ADC0.
Description
Package
Q1
Pin No.
1
2
3
5
7
8
9
11
14
16
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
59
61
63
64
©
2004 CML Microsystems Plc
5
D/990/1
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