Half Duplex GMSK Modem
FX579
Characteristic
Note
Min.
Typ.
Max.
Units
Transmit Parameters
TXOP output impedance
TXOP output level
3
-
0.8
-100
-
100
1.0
-
2.0
1.5
-
W
4, 6, 9
1.2
+100
2.5
Vpk-pk
mV
bit periods
bit periods
Tx output offset (wrt V
)
-
5
5
BIAS
Tx data delay (BT = 0.3)
Tx data delay (BT = 0.5)
-
2.0
Receive Parameters
RXIN input impedance
RXIN input level
3
1.0
±0.5
-
-
1.3
-
MW
Vpk-pk
V
7, 9
9
8
0.7
-
-
Rx dc offset from ½ V
Rx time delay
DD
3
bit periods
On-Chip Xtal Oscillator
Input impedance
Output impedance
Voltage gain
"High" clock pulse width
"Low" clock pulse width
10
10
10
11
11
10
-
-
60
60
-
-
-
-
-
MW
kW
dB
ns
50
25
-
-
ns
Notes:
1.
2.
3.
Not including any current drawn from the modem pins by external circuitry
For V in the range V to V
Measured by ac coupling an external 1kHz source via suitable resistance to the TXOP pin.
The value specified is the average of values measured in the all "1"s and all "0"s states
Data pattern of "1111000011110000..."
IN
SS
DD
4.
5.
Measured between the rising edge of the Tx DATACLK and the centre of the corresponding bit
at the output of the external RC network connected to TXOP
6.
7.
8.
Measured at the output of the external RC network
For optimum performance, measured at RXIN for a "1111000011110000..." pattern
Measured between the centre of bit at RXIN and corresponding rising edge of the
Rx data clock
9.
Levels are proportional to applied V
DD
10.
11.
Small signal measurement at 100Hz with no load on XTALN output
Timing for an external clock input to the XTAL/CLK pin
ã 1996 Consumer Microcircuits Limited
21
D/579/4
CMLMICRO [ CML MICROCIRCUITS ]
