MC34118DW Freescale Semiconductor, MC34118DW Datasheet - Page 11

• 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: -

With an appropriate choice of an input coupling capacitor to
the low pass filter, a band pass filter is formed.
POWER SUPPLY, V
3.5 and 6.5 volts for normal operation, with reduced opera-
tion possible down to 2.8 volts (see Figure 15 and the AGC
section). The power supply current is shown in Figure 18 for
both the power--up and power--down mode.
MOTOROLA
-- 3.0
-- 30
The power supply voltage at V
f
0
FOR R1 = R2
+ 10
-- 10
-- 20
-- 30
-- 40
-- 50
N
Figure 10. Attenuator Gain versus V
-- 240
0
= 1
2π

-- 160
C1C2R 2
Figure 9. Low Pass Filter
1
ATTENUATOR
4.0 k
TRANSMIT
f
N
B
, AND CHIP DISABLE
-- 80
20 k
V
CT
V
C1
in
V
-- V
R1
13 k
B
0
CC
B
(mV)
0.01
13 k
(Pin 4) is to be between
R2
220 k
0.001
V
CC
+ 80
≥ 3.5 V
ATTENUATOR
CT
C2
RECEIVE
FI
(Pin 14)
MC34118
+ 160
+ 1
FO
+ 240
provides the ac ground for the system. The output imped-
ance at V
with the external capacitor at V
power supply rejection. Figure 20 indicates the amount of re-
jection with different capacitors. The choice of capacitor is
application dependent based on whether the circuit is pow-
ered by the telephone line or a power supply.
amount of supply rejection at their outputs is directly related
to the rejection at V
ure 21 depicts this graphically.
conserve power and/or for muting purposes. With CD
≤ 0.8 volts, normal operation is in effect. With CD ≥ 2.0 volts
and ≤ V
mode, the microphone and the hybrid amplifiers are dis-
abled, and their outputs go to a high impedance state. Addi-
tionally, the bias is removed from the level detectors. The
bias is not removed from the filter (Pins 1, 2), the attenuators
(Pins 8, 9, 21, 22), or from Pins 13, 14, and 15 (the attenua-
tors are disabled, however, and will not pass a signal). The
input impedance at CD is typically 90 kΩ, has a threshold of
≈1.5 volts, and the voltage at this pin must be kept within the
range of ground and V
the pin should be grounded.
Figure 11. Level Detector DC Transfer Characteristics
140
120
100
The output voltage at V
Since V
The Chip Disable (Pin 3) permits powering down the IC to
80
60
40
20
0
0
CC
B
B
, the IC is powered down. In the powered down
biases the microphone and hybrid amplifiers, the
is ≈400 Ω (see Figure 19), and in conjunction
-- 20
(RLI1, RLI2
TLI1, TLI2)
B
, as well as their respective gains. Fig-
DC INPUT CURRENT (µA)
CC
I
in
-- 40
VB
(see Figure 17). If CD is not used,
B
(Pin 15 is ≈(V
--
+
B
, forms a low pass filter for
(RLO1, RLO2
TLO1, TLO2)
-- 60
V
out
2.0 µF
350 Ω
CC
-- 80
-- 0.7)/2, and
MC34118
4.0
µA
-- 100
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