TCA3388 Datasheet, PDF (7/16 Pages) Motorola, Inc – TELEPHONE LINE INTERFACE

TCA3388
DC CHARACTERISTICS AND STARTUP
The dc mask has the general form as depicted in Figure 3.
The TCA3388 offers the possibility to adjust the dc
characteristics of all 4 regions via mask selection and
hardware adjustments.
The selection of the 3 masks, France, United Kingdom
and Low Voltage, can be done via the ZDCM network at Pin
DCM as shown in Figure 4. For French and U.K. masks, the
region 3 with the high slope is within the normal dc feeding
conditions. For Low Voltage mask the region 3 will be outside
this and the dc mask is mainly determined by regions 1
and 2.
Figure 3. General Form of the DC Mask
of the TCA3388
VLine
Figure 4. Selection of the Country Mask via Pin DCM
IDCM (µA)
14
11
FR
U.K.
LV
4
0
0.5
2.0 2.5 3.0 3.2
VDCM(V)
ZDCM for the L.V., U.K. and FR Mask
DCM
VCC
DCM
DCM
4
VLP
3
VLK
2
VLC
1
R23
56 k
R24
C21
R25
C18
47 k
10 µ
1.0 M
470 n
L.V.
U.K.
FR
0
ILine
ILC
ILP
ILK IVLP
Region 1: Startup, Low Line Current, High Slope
Region 2: Mid–Range Line Current, Low Slope
Region 3: High Line Current, High Slope
Region 4: Overload Protection
The capacitor in the U.K. network is to ensure a stable
selection of the mask during all working modes and
transitions. The capacitor in the French network is used to
create a startup in Low Voltage Mask.
The adjustment possibilities will be discussed below with
the aid of the block diagram of Figure 5.
Line +
Z2
Line –
Figure 5. DC Part of the Block Diagram of the TCA3388
C16 _IMP
Z1
I2L
HYL
CM
G
1.6 V
2 VBE
I2S
G
HYS
RX
CM
VO1
SAI
Z0
Z21
LAI
SAO
VO2
TCA3388
R1
T2
R5
LAO
T3
Gnd
VCC
C7
MOTOROLA ANALOG IC DEVICE DATA
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