MC34118DW Freescale Semiconductor, MC34118DW Datasheet - Page 19

• Manufacturer Part Number: MC34118DW
• Description: IC VOICE SWITCH SPKPHONE 28-SOIC
• Manufacturer: Freescale Semiconductor

Specifications of MC34118DW

• Function: Voice-Switched Speakerphone
• Number Of Circuits: 1
• Voltage - Supply: 3.5 V ~ 6.5 V
• Current - Supply: 5.5mA
• Operating Temperature: -20°C ~ 60°C
• Mounting Type: Surface Mount
• Package / Case: *
• Includes: Background Noise Monitor, Chip Disable, Dial Tone Detector, Driver Amplifiers, Level Detectors, Microphone Amplifier, MUTE
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power (watts): -
• Interface: -

ringer, dialer, and handset functions. The circuit is powered
entirely by the telephone line’s loop current, and its charac-
teristics are shown in Figures 27 -- 30.
MOTOROLA
Figure 29. Transmit Gain — Microphone to Tip/Ring
1000
50
48
46
44
40
8.0
4.0
24
20
16
12
800
600
400
200
0
100
0
100
Figure 28. AC Termination Impedance
Figure 27. DC V- -1 Characteristics
20
0.2
40
LOOP CURRENT (mA)
V
600
M
FREQUENCY (Hz)
FREQUENCY (Hz)
5.1 k
GAIN = V
R
T
FIGURE 23
1.0K
MCI
60
1.0K
LINE
FIGURE 23
Z
ac
/V
M
80
R
T
600
V
5.0K
LINE
100
5.0K
120
be powered from a 3.5 -- 6.0 volt power supply rather than
the phone line.
ADDING A DIALER
ure 23, with the additional components shown in bold. The
MC145412 pulse/tone dialer is shown configured for DTMF
operation. The DTMF output (Pin 18) is fed to the hybrid am-
plifiers at HTI, and the DTMF levels at Tip/Ring are adjusted
by varying the 39 kΩ resistor. The Mute Output (active low at
Pin 11) mutes the microphone amplifier, and attenuates the
DTMF signals in the receive path (by means of the 10 k/3.0 k
divider). The MC34118 is forced into the fast idle mode dur-
ing dialing. The 3.0 volt battery provides for memory reten-
tion of the dialer’s 10 number storage when the circuit is
unpowered.
RFI INTERFERENCE
addressed early in the electrical and mechanical design of
the speakerphone. RFI may enter the circuit through Tip and
(MC34119)
Figure 31 shows how the same circuit can be configured to
Figure 32 shows the addition of a dialer to the circuit of Fig-
Potential radio frequency interference problems should be
TO V
FILTER
28
26
24
22
20
TO CD
TO CD
HTO--
HTO+
100
TO
TO
TO
CC
Figure 31. Operating from a Power Supply
(NOTE 1)
100 µF
300
Figure 30. Receive Gain
820
0.05
500
FREQUENCY (Hz)
GAIN = V
0.01
DISABLE
600
V
L
1.0K
R
T
SPKR
FIGURE 23
1. This capacitor must be
/V
L
physically adjacent to
Pin 4 of the MC34118.
SWITCH
HOOK
+
--
V
5.0K
SPKR
MC34118
FROM
POWER
SUPPLY
RING
TIP
19