
1200/2400/4800 Baud FFSK/MSK Modem
CMX469A
2001 Consumer Microcircuits Limited
11
D/469A/2
Operating Limits
Correct operation of the device outside these limits is not implied.
Supply (V
DD
- V
SS
)
Operating Temperature
Xtal Frequency
Note 1: A Xtal frequency of 1.008MHz (1200/2400 baud only) or 4.032MHz is required for correct
operation. A frequency tolerance of ±0.1% is recommended, but ultimately the tolerance selected will
depend upon system requirements.
Operating Characteristics
For the following conditions unless otherwise specified:
V
DD
= 2.7V at Tamb = 25
°
C and V
DD
= 3.0V to 5.5V at Tamb =
40
°
C to +85
°
C,
Xtal/Clock Frequency = 4.032MHz, Bit Rate = 1200 baud, Rx Input Level = 300mVrms.
Static Values
I
DD
Rx Enabled, Tx Disabled (V
DD
= 5.0V)
I
DD
Rx and Tx Enabled
(V
DD
= 5.0V)
I
DD
Rx and Tx Disabled
(V
DD
= 5.0V)
I
DD
Rx Enabled, Tx Disabled (V
DD
= 3.0V)
I
DD
Rx and Tx Enabled
(V
DD
= 3.0V)
I
DD
Rx and Tx Disabled
(V
DD
= 3.0V)
Logic ‘1’ Level
Logic ‘0’ Level
Digital Output Impedance
Analogue and Digital Input Impedance
Tx Output Impedance (V
DD
= 5.0V)
Dynamic Values
Receiver
Signal Input Dynamic Range SNR = 50dB
Bit Error Rate at SNR = 12dB
1200 Baud
2400 Baud
4800 Baud
Bit Error Rate at SNR = 20dB
1200/2400/4800 Baud
Receiver Synchronization at SNR = 12dB
probability of bit 16 being correct
Notes
1
Min.
2.7
-40
4.028
Max.
5.5
+85
4.036
Units
V
°C
MHz
Notes
2
2
2
2
2
2
1
1
3, 4
4, 5
4, 5
Min.
-
-
-
-
-
-
70%
-
-
100
-
100
-
-
-
-
-
Typ.
3.6
4.5
650
1.5
2.0
300
-
-
4.0
-
0.6
230
2.5
1.5
1.5
<1.0
0.995
Max.
-
-
-
-
-
-
-
30%
-
-
1.0
1000
-
-
-
Units
mA
mA
μA
mA
mA
μA
V
DD
V
DD
k
k
k
mVrms
10
10
10
10
-4
-3
-3
-
-
-8
7