75T2089/2090/2091
DTMF Transceivers
4
DTMF OUT
The output amplitude characteristics listed in the
specifications are given for a supply voltage of 5.0V.
However, the output level is directly proportional to
the supply, so variations in it will affect the DTMF
output. A recommended line interface for this output
is shown in Figure 5.
CALL PROGRESS DETECTION
(75T2090/2091)
The 75T2090/2091 have a Call Progress Detector
that consists of a bandpass filter and an energy
detector for turning the on/off cadences into a
microprocessor compatible signal.
DET OUTPUT (75T2090/2091)
The output is TTL compatible and will be of a
frequency corresponding to the various candences
of Call Progress signals such as: on 0.5 sec/off 0.5
sec for a busy tone, on 0.25 sec/off 0.25 sec for a
reorder tone and on 0.8-1.2 sec/off 2.7-3.3 sec for
an audible ring tone.
LIN INPUT (75T2090/2091)
This analog input accepts the call progress signal
and should be used in the same manner as the
receiver input DIN.
FIGURE 5: DTMF Output
ELECTRICAL SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Operating above absolute maximum ratings may damage the device.
PARAMETER
DC Supply Voltage (Vp - Vn)
RATING
+7V
Voltage at any Pin (Vn = 0)
-0.3 to Vp + 0.3V
DIN Voltage
Current through any Protection Device
Vp + 0.5 to Vp - 10V
=
20mA
Operating Temperature Range
-40 to + 85
°
C
-65 to 150
°
C
Storage Temperature
RECOMMENDED OPERATING CONDITIONS
PARAMETER
CONDITIONS
MIN
NOM
MAX
UNIT
Supply Voltage
4.5
5.5
V
Power Supply Noise (wide band)
Ambient Temperature
10
+85
mVp-p
°
C
%
-40
Crystal Frequency
-0.01
+0.01
(F Nominal = 3.579545MHz)
Crystal Shunt Resistor
0.8
1.2
M
DTMF OUT Load Resistance
100
DTMF
OUT
1:1
TIP
100
RING