CMX589A CML Microcircuits COMMUNICATION SEMICONDUCTORS GMSK Modem D/589A/4 April 2002 Features and Applications Data Rates from 4kbps to 200kbps Portable Wireless Data Applications Cellular Digital Packet Data (CDPD) Full or Half Duplex Gaussian Filter and Data Mobitex Mobile Data System Recovery for Minimum Shift Keying (GMSK) Designs Spread Spectrum Data Links Selectable BT: (0.3 or 0.5) GPS/Differential GPS Wireless Links Low Power Point-of-Sale Terminals 3.0V, 20kbps, 1.5mA typ. Low Power Wireless Data Link for PCs, 5.0V, 64kbps, 4.0mA typ. Laptops, and Printers Low Current Non-DSP Solution Small TSSOP Packs fit PCMCIA/PC Cards Brief Description The CMX589A is a single-chip synchronous data pump/modem designed for Wireless Data Applications. Employing Gaussian filtering for Minimum shift Keying (GMSK) baseband modulation applications, the CMX589A features a wide range of available data rates from 4k to 200k bps. Data Rates and the choice of BT (0.3 or 0.5) are pin programmable to provide for different system requirements. The Tx and Rx digital data interfaces are bit serial, synchronized to generated Tx and Rx data clocks. Separate Tx and Rx Powersave inputs allow full or half-duplex operation. Rx input levels can be set by suitable AC and DC level adjusting circuitry built with external components around an on-chip Rx Input Amplifier. Acquisition, Lock, and Hold of Rx data signals are made easier and faster by the use of Rx Control Inputs to clamp, detect, and /or hold input data levels and can be set by the Processor as required. The Rx S/N output provides an indication of the quality of the received signal. The CMX589A may be used with a 3.0V to 5.5V power supply and is available in the following packages: 24-pin TSSOP (CMX589AE2), 24-pin SSOP (CMX589AD5), 24-pin SOIC (CMX589AD2), and 24-pin PDIP (CMX589AP4). 2002 CML Microsystems Plc GMSK Modem CMX589A Contents Section Page Features and Applications .................................................................................................1 Brief Description .................................................................................................................1 Block Diagram.....................................................................................................................3 2 Signal List.........................................................................................................................4 3 External Components ......................................................................................................6 4 General Description .........................................................................................................8 4.1 Clock Oscillator Divider.........................................................................................................8 4.2 Receive.................................................................................................................................8 4.2.1 Rx Signal Path Description.....................................................................................................8 4.2.2 Rx Circuit Control Modes .......................................................................................................9 4.2.3 Rx Clock Extraction..............................................................................................................10 4.2.4 Rx Data Extraction...............................................................................................................10 4.2.6 Rx Signal Quality .................................................................................................................12 4.3 Transmit..............................................................................................................................12 4.3.1 Tx Signal Path Description...................................................................................................12 4.4 Data Formats......................................................................................................................14 4.5 Acquisition and Hold Modes ...............................................................................................14 5 Application......................................................................................................................15 5.1 Radio Channel Requirements.............................................................................................15 5.1.1 Bit Rate, BT, and Bandwidth ................................................................................................15 5.1.2 FM Modulator, Demodulator and IF......................................................................................15 5.1.3 Two-Point Modulation...........................................................................................................16 5.2 AC Coupling of Tx and Rx Signals .....................................................................................17 6 Performance Specifications ..........................................................................................18 6.1 Electrical Specifications......................................................................................................18 6.1.1 Absolute Maximum Limits ....................................................................................................18 6.1.2 Operating Limits...................................................................................................................19 6.1.3 Operating Characteristics.....................................................................................................20 6.2 Packages............................................................................................................................22 2002 CML Microsystems Plc 2 D/589A/4