CML Semiconductor Products
PRODUCT INFORMATION
FX589
Features
Full-Duplex Gaussian Minimum
Shift Keying (GMSK)
Operating from 3 Volts to 5.5 Volts
Data Rates 4kb/s to 64kb/s
Selectable BT (0.3 or 0.5)
Low-Current Analogue/Digital
Non-DSP Solution
Meets RCR STD-18
Tx ENABLE
Tx PS
Tx DATA
V
BIAS
Low-Voltage/High-Speed
GMSK Modem
Publication D/589/7 January 1998
Applications
Wireless LAN/Modems
Handy Data Terminals
Low-Power Wireless Data Link
for PCs, Laptops and Printers
Point-Of-Sale Terminals
Wireless Bar-Code Readers
and Stock Controllers
V
BIAS
DATA RETIME
&
LEVEL SHIFT
Tx
FILTER
Tx OUT
XTAL/CLOCK
Tx CLOCK
XTAL
ClkDIVA
ClkDIVB
CLOCK
DIVIDER
Rx DATA
EXTRACT
Rx DATA
BT
Rx S/N
DETECTION
Rx S/N
FX589
RxHold
PLLacq
RxDCacq
Rx PS
Rx CIRCUIT
CONTROL
Rx CLOCK
EXTRACT
Rx CLOCK
V
DD
V
BIAS
Rx SIGNAL IN
+
-
Rx
FILTER
Rx LEVEL
MEASURE
V
SS
V
BIAS
Rx FEEDBACK
DOC1
DOC2
Fig.1 Functional Block Diagram
Brief Description
The FX589 is a single-chip modem employing
Gaussian Minimum Shift Keying (GMSK) modulation.
Data rates of 4kb/s to 64kb/s and the choice of BT
to 0.3 or 0.5 are pin-programmable functions to suit
radio data channel bandwidth requirements.
The Rx and Tx digital data interfaces are bit-serial
and synchronised to Rx and Tx data clocks generated
by the modem. Separate Rx and Tx Powersave/Enable
inputs allow for full- or half-duplex operation.
Rx input levels can be set by a suitable ac and dc
level adjusting circuit built, with external components,
around an on-chip Rx input amplifier.
Acquisition, lock and hold of Rx data signals is 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
system µProcessor as required.
Indication is available, from the Rx S/N output, as to the
quality of the received signal.
The FX589 design features a low-current analogue/digital
ASIC process offering significantly lower current
consumption than DSP technology. For data rates up to
32kb/s the FX589 draws typically 1.5mA at 3.0 volts V
DD
and
for data rates up to 64kb/s at 5.0 volts, typically 4.0mA.
This low-power CMOS microcircuit is available in both
24-pin plastic DIL and Small Outline (SOIC and SSOP)
packages.
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