Order this document by MC33218A/D
VOICE SWITCHED
SPEAKERPHONE WITH
µPROCESSOR INTERFACE
The Motorola MC33218A Voice Switched Speakerphone Circuit
incorporates the necessary amplifiers, attenuators, level detectors, and
control algorithm to form the heart of a high quality hands–free
speakerphone system. Included are a microphone amplifier with mute,
transmit and receive attenuators, a background monitoring system for both
the transmit and receive paths, and level detectors for each path. An AGC
system reduces the receive gain on long lines where loop current and power
are in short supply. A dial tone detector prevents fading of dial tone. A Chip
Disable pin permits conserving power when the circuit is not in use.
Additionally, the MC33218A has a serial data port which permits
microprocessor control of the receive volume level, microphone mute,
attenuator range, and selection of transmit, receive, idle or normal modes.
The data port can be operated at up to 1.0 MHz.
SEMICONDUCTOR
TECHNICAL DATA
24
1
P SUFFIX
PLASTIC PACKAGE
CASE 724
The MC33218A can be operated from a power supply, or from the
telephone line, requiring typically 4.6 mA. It can be used in conjunction with a
variety of speech networks. Applications include not only speakerphones,
but intercoms and other voice switched devices.
• Supply Voltage Range: 2.7 to 6.5 V
24
• Attenuator Range: 53 or 27 dB (Selectable)
• 2 Point Sensing with Background Noise Monitor in Each Path
• Microprocessor Port for Control of:
Volume Control (40 dB Range over 16 Levels)
Mute Microphone Amplifier
1
DW SUFFIX
PLASTIC PACKAGE
CASE 751E
Force to Receive, Transmit, or Idle Modes
Attenuator Range Selection (27 or 53 dB)
PIN CONNECTIONS
• Chip Disable Pin Powers Down the Entire IC
• 24 Pin Narrow Body (300 mil) DIP and 24 Pin SOIC
CP2
XDI
CPT
TLI
1
24
23
22
21
20
19
18
17
16
15
14
13
V
CC
2
TAO
MCO
MCI
3
Simplified Block Diagram
4
Transmit
Out
TLO
5
POR
DR
Microphone
V
6
B
Receive
In
C
7
DATA
CLK
RXI
T
V
B
T
Attenuator
x
V
B
CD
NC
8
9
V
B
BNM
Attenuator Control
CPR
RLI
10
11
12
RXO
RAO
GND
CLK
DATA
POR
Serial
Port
DTD
RLO
DR
CD
CC
BNM
R
Attenuator
x
V
(Top View)
B
V
Reg.
V
B
MC33218A
ORDERING INFORMATION
Operating
Temperature Range
Device
Package
Speaker
Amplifier
Speaker
MC33218ADW
MC33218AP
SO–24L
T
= – 40° to +85°C
A
This device contains 610 active transistors.
Plastic DIP
This document contains information on a new product. Specifications and information herein are
subject to change without notice.
Motorola, Inc. 1995
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MOTOROLA ANALOG IC DEVICE DATA