MT88E43BS1 Zarlink, MT88E43BS1 Datasheet - Page 9

• Manufacturer Part Number: MT88E43BS1
• Description: Caller ID CMOS 3.58MHz 3.3V/5V 24-Pin SOIC Tube
• Manufacturer: Zarlink

Specifications of MT88E43BS1

• Package: 24SOIC
• Telecommunication Standards Supported: GR-30|SIN227|SIN242|SR-TSV-002476|TR-NWT-000030
• Fabrication Technology: CMOS
• Maximum Data Rate: 1212 Bd
• Typical Operating Supply Voltage: 3.3|5 V
• Typical Supply Current: 3 mA
• Minimum Operating Temperature: -40 °C
• Maximum Operating Temperature: 85 °C
• Operating Frequency: 3.58 MHz

FSK Demodulation
The MT88E43 first bandpass filters and then demodulates the incoming FSK signal. The carrier detector provides
an indication of the presence of signal at the bandpass filter output. The MT88E43’s dual mode 3-wire interface
allows convenient extraction of the 8-bit data words in the demodulated FSK bit stream.
Note that signals such as dual tone alert signal, speech and DTMF tones lie in the same frequency band as FSK.
They will, therefore, be demodulated and as a result, false data will be generated. To avoid demodulation of false
data, an FSKen pin is provided so that the FSK demodulator may be disabled when FSK signal is not expected.
There are two events that if either is true, should be used to disable FSKen. The events are CD returning high or
receiving all the data indicated by the message length word.
Mark
frequency
(logic 1)
Space
frequency
(logic 0)
Received
signal level -
mark
Received
signal level -
space
Differential Input Amplifier
Voltage Gain
(A
C1 = C2
R1 = R4 (For unity gain R5= R4)
R3 = (R2R5) / (R2 + R5)
Input Impedance
(Z
V
IN
diff) = R5/R1 (see Figure 9,10,11)
diff) = 2
Figure 7 - Differential Input Configuration
Item
C2
C1
Table 2 - FSK Characteristics
R1
R1
R4
2
Zarlink Semiconductor Inc.
+ (1/ωC)
R3
MT88E43B
(-5.78dBm to
-37.78dBm)
-8dBV to
-8dBV to
1300Hz
2100Hz
-40dBV
-40dBV
±1.5%
±1.5%
2
BT
9
R2
R5
IN+
IN-
GS
V
Ref
-12dBm
-12dBm to
Bellcore
-32dBm
-36dBm
1200Hz
2200Hz
±1%
±1%
1
to
Data Sheet