tca3388 Freescale Semiconductor, Inc, tca3388 Datasheet - Page 6

• Manufacturer Part Number: tca3388
• Description: Advance Information Telephone Line Interface
• Manufacturer: Freescale Semiconductor, Inc

Concept
telephone set can be built according to the concept depicted
in Figure 1.
The line current flows through transistor T2 and supplies the
externals (microcontroller) at the supply point V CC which is
stabilized by the TCA3388. The V line , I line characteristic is
adjusted by the external components Z0, Z1, Z21 and R1
which are in a regulator loop, acting on transistor T2. The ac
6
With a TCA3388, a microcontroller and a ringer, a basic
In off–hook position, the application is in speech mode.
A/B
Line +
Line –
C20
R9
R6
Hookswitch
Ringer
C5
RXO1
RXO2
RXI
TXI
Mic
Figure 2. Block Diagram of the TCA3388 with Essential Components
19
20
1
2
3
Mute, AGC
Mute, AGC
Mic
TCA3388
Ear
Figure 1. Telephone Concept with TCA3388
DESCRIPTION OF THE CIRCUIT
Z2
11
7
Handset
HYS
SAI
C17
R19
Z
R1
DCM
DC Mask Generation
2–4 Wire Conversion
Line Length AGC
TCA3388
12
AC Termination
R20
Protection
DCM
6
Z1
R22
HYL
Z1
13
8
Micro–Interface
impedance is generated in a similar way. The handset can be
connected directly to the TCA3388. Via a logic level interface,
the microcontroller drives the TCA3388 to perform the
DTMF/pulse–dialing. The user keyboard has to be connected
to the microcontroller. In on–hook position, a ringing melody
can be generated with a ringer application.
basic blocks of the device plus the essential external
components.
TCA3388
HSO
Z21
Hook–Detect
R1
CM
The block diagram of the TCA3388, in Figure 2, shows the
C16
PABX
Microcontroller
14
10
To/From
PI
15
SAO
Z0
Z21
MUT
Z0
5
MOTOROLA ANALOG IC DEVICE DATA
LAI
DTMF
9
T2
References
Line
Driver
Stabilizer
Supply–
IMP
16
V CC
Gnd
I
ref
R12
Micro
V
17
Gnd
18
LAO
4
CC
T3
T2
C7