DSL01-xxxSC5
Product Page
With the increase in the use of video phones it has become critical
to further increase the bandwidth of telecommunication lines. When
using ADSL2+ (2.2 MHz) or VDSL (12 MHz) it is mandatory to minimize
losses and distortion on twisted pairs. Whatever the signal, equipment
must comply with various surge standards that simulate lightning
and power faults, such as ITU-T-K20/21, TIA/EIA-IS-968 or UL60950. |
|
Protected error-free data transmission is the main
objective.
|
State-of-the-art
solutions |
|
Protection is generally implemented using gas discharge tubes (GDT)
or a Trisil on the primary side. However, the reliability of GDTs
is subject to question and the capacitance of the Trisil is quite
often a problem. This results in designers trying to include the
protection after the DSL transformer. In this case requirements
are different, and the key point is to keep the surge voltage below
the maximum voltage of the line drivers and not to disturb transmission.
Current solutions are either, Metal Oxide Varistors (MOV), zener
diodes or small rail to rail diodes.
|
Current solutions
and DSL01 comparison |
|
Key
value
|
MOV
|
Zener
|
Rail-to-rail
|
DSL |
Surge
capability |
High |
Low |
Low |
Low |
Max voltage |
Too High |
Too High |
Too High |
Low |
Capacitance |
Medium |
Low |
Very Low |
Low |
Technology |
ZNo grain
between 2
pins |
Monolithic
small planar
wire
bonding |
Dual dice
small signal
bipolar planar
wire bonding |
Monolithic
planar on
single frame
wire bonding |
Quality |
Deteriorates |
Good |
Good |
Very good |
Aging |
Yes |
No |
No |
No |
MOVs provide poor protection after several surges and a degradation
of performance can affect transmission.
Zener diodes are not protection devices and are unable to prevent
high voltage online driver output. Rail-to-rail diodes have a too
high dynamic forward voltage to limit voltage across line drivers.
The DSL01 family
provides the solution |
The DSL01 does not generate signal distortion and is compliant with
GR1089, ITU-T K20/21 when located after the DSL transformer. The
DSL01 is a reliable planar technology device, with no ageing, and
guarantees drivers running to avoid field failure returns. The key
added values of the DSL01 are:
High surge capability (IPP) to withstand GR-1089 and
ITU-T K20/21 after the DSL transformer
Low voltage during surge (VCL) to avoid line driver damage
Low capacitance to ensure data integrity
ASD technology combines two main functions on one chip: clamping
and crowbar protection. A Transil ensures low-energy surges while
a Trisil short circuits high-energy surges to ensure low voltages.
The DSL01 has been developed in 8 V and 16 V versions to be used
in tripolar protection, while some modems require only common or
differential modes (other voltages are in development).
Tripolar protection for DSL line drivers
Part
number
|
Package
|
Leakage
current
|
Breakdown
voltage
|
C max
at
0 V bias |
|
SOD23-5L |
Ir<500 nA at
8 V
|
Vbr>9.5 V at
1 mA
|
20 pF |
|
Ir<500 nA at
16 V |
Vbr>18 V at 1
mA |
15 pF
|
|
|
|
|
