MT8910-1 Mitel Networks Corporation, MT8910-1 Datasheet - Page 20

• Manufacturer Part Number: MT8910-1
• Description: CMOS St-bus Family Digital Subscriber Line Interface Circuit
• Manufacturer: Mitel Networks Corporation

MT8910-1
The termination network is an all passive circuit
which allows the MT8910-1 to interface to the DSL
line through a line pulse transformer. The passive
line termination consists of three blocks which
includes a hybrid network, a compensator circuit and
a line pulse transformer (refer to Figures 13 and 14).
The hybrid network is a 2 to 4 wire converter which
provides limited precancellation of near end echo.
The hybrid specified in Figure 13 was optimized for
the specified transformer and a 10 ohm series
protection resistor (Rp).
The compensator circuit, in conjunction with the
transformer, acts as a high pass filter which is
designed to increase the cut-off frequency in the
receiver path. This has the effect of reducing the low
frequency content in the received line signal which in
turn reduces the effects of ISI and near end echo
thereby improving transceiver performance.
The low inductance transformer allows for the
possibility of passing a sealing current and/or
phantom feed supply through the secondary winding
without
transformer specified in Figure 14 has been
designed to carry typically 50 mA of DC current.
9-22
Passive Line Termination Network (PLT)
saturating
CONVERTER
TO DC-DC
the
1.5 F
Figure 12 - Typical Connections for NT Mode (Single Port)
magnetic
1.0 F
V
DD
0.1 F
0.1 F
core.
PLT
M
H
8
9
1
0
1
1.0 F
The
1 F
1 F
22
24
28
27
25
26
23
11
10
2
1
9
VDD
AVDD
Lout+
Lin+
Lin-
Lout-
VBias
VRef
CDSTo
IC
TSTout
F0od
Transformer Specification
All subscriber equipment which is to be connected to
a digital subscriber line, must deliver an output pulse
which satisfies both the pulse template and the pulse
PSD as specified earlier.
characteristics
transformer with a turns ratio of 1:1.3 having the
electrical characteristics specified in Figure 14.
For
Semiconductor has made available the MB6024
Magnetic Kit which contains the transformer shown
in Fig. 14.
MT8910-1
supporting
TSTen
CDSTi
MRST
OSC1
OSC2
NT/LT
TSTin
AVSS
DSTo
DSTi
MS0
MS1
VSS
C4b
SFb
F0b
19
17
18
16
12
13
14
15
20
6
8
4
5
21
7
3
of
initial
33pF
Preliminary Information
V
10.24 MHz
the
DD
Xtal
design
MT8910-1
33pF
System Reset
PCM OR
DATA
The output drive
CLOCKS
activities,
requires
Mitel
a