MC34118P Freescale Semiconductor, MC34118P Datasheet - Page 20

• Manufacturer Part Number: MC34118P
• Manufacturer: Freescale Semiconductor

Specifications of MC34118P

• Operating Supply Voltage (typ): 5V
• Max Transmitter Gain: 8dB
• Receiver Gain (max): 8dB
• Operating Temp Range: -20C to 60C
• Package Type: PDIP
• Pin Count: 28
• Operating Current: 5.5mA
• Operating Temperature Classification: Commercial
• Mounting: Through Hole
• Operating Supply Voltage (max): 6.5V
• Operating Supply Voltage (min): 3.5V
• Lead Free Status / Rohs Status: Not Compliant

Ring, through the microphone wiring to the microphone am-
plifier, or through any of the PC board traces. The most sen-
sitive pins on the MC34118 are the inputs to the level
detectors (RLI1, RLI2, TLI1, TLI2) since, when there is no
speech present, the inputs are high impedance and these op
amps are in a near open loop condition. The board traces to
these pins should be kept short, and the resistor and capaci-
tor for each of these pins should be physically close to the
pins. Any other high impedance input pin (MCI, HTI, FI, VLC)
should be considered sensitive to RFI signals.
IN THE FINAL ANALYSIS . . .
proper mechanical (acoustic) design as well as proper elec-
tronic design. The acoustics of the enclosure must be con-
sidered early in the design of a speakerphone. In general,
electronics cannot compensate for poor acoustics, low
speaker quality, or any combination of the two. Proper
acoustic separation of the speaker and microphone, as de-
scribed in the Design Equations, is essential. The physical
location of the microphone, along with the characteristics of
the selected microphone, will play a large role in the quality
of the transmitted sound. The microphone and speaker ven-
dors can usually provide additional information on the use of
their products.
will have to be “fine tuned” to match the acoustics of the en-
closure, the specific hybrid, and the specific microphone and
speaker selected. The component values shown in this data
sheet should be considered as starting points only. The gains
of the transmit and receive paths are easily adjusted at the
microphone and speaker amplifiers, respectively. The
switching response can then be fine tuned by varying (in
small steps) the components at the level detector inputs until
MC34118
20
Proper operation of a speakerphone is a combination of
In the final analysis, the circuits shown in this data sheet
16
15
14
13
2
5
4
3
3.0 V
MC145412
*
1
4
7
2
5
8
0
3
6
9
#
18
10
12
11
1
8
9
6
A
B
C
D
0.1
0.1
2.0 k
3.58
MHz
Figure 32. Adding a Dialer to the Speakerphone
V
CC
4
39 k
V
CC
MUTE
MC34118
8
0.1
TXO
27 k
240 k
10 k
satisfactory operation is obtained for both long and short
lines.
SUGGESTED VENDORS
Microphones
25 Ω Speakers
Telecom Transformers
Motorola Inc. does not endorse or warrant the suppliers
referenced.
MUT
HTI
Primo Microphones Inc.
Bensenville, IL 60106
312--595--1022
Model EM--60
Hosiden America Corp.
Elk Grove Village, IL 60007
312--981--1144
Model KUC2123
Panasonic Industrial Co.
Seacaucus, N.J. 07094
201--348--5233
Model EAS--45P19S
Microtran Co., Inc.
Valley Stream, N.Y. 11528
516--561--6050
Various models — ask for
catalog and Application
Bulletin F232
PREM Magnetics, Inc.
McHenry, IL 60050
815--385--2700
Various models — ask for
catalog
V
B
7
12
+
--
51 k
3300
R
6
FO
V
HTO--
B
FILTER
1
--
+
2N2222A
OR EQUIVALENT
56 k
+ 1
R
300
820
2
FI
HTO+
5
0.05
MURA Corp.
Westbury, N.Y. 11590
516--935--3640
Model EC--983--7
Stancor Products
Logansport, IN 46947
219--722--2244
Various models — ask for
catalog
Onan Power/Electronics
Minneapolis, MN 55437
612--921--5600
Model TC 38--6
180 k
4700 pF
0.01
MOTOROLA
10 k
3.0 k
TO TIP
& RING