WJLXT384LE.B1-868635 Cortina Systems Inc, WJLXT384LE.B1-868635 Datasheet - Page 51

• Manufacturer Part Number: WJLXT384LE.B1-868635
• Manufacturer: Cortina Systems Inc

Specifications of WJLXT384LE.B1-868635

• Screening Level: Industrial
• Mounting: Surface Mount
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Lead Free Status / RoHS Status: Compliant

LXT384 Transceiver
Datasheet
248994, Revision 6.0
30 January 2008
Figure 5
Note:
6.4.2
Note:
Caution:
Cortina Systems
50% AMI Encoding
Each output driver is supplied by its own TVCC and TGND power-supply pins. The transmit
pulse shaper is bypassed if no MCLK is supplied. When in this condition, if TCLK is pulled
High, then TPOS and TNEG control the pulse width and polarity on TTIP and TRING. With
MCLK supplied and TCLK pulled High, the driver enters TAOS (Transmit All Ones pattern).
The TAOS generator uses MCLK as a timing reference. To ensure that the output frequency
is within specification limits, MCLK must have the applicable stability. TAOS is inhibited
during Remote Loopback.
Transmitter Pulse Shaping
Pulse shaping is a means of converting an input logic ‘1’ into a valid output mark so that the
output pulse can be changed (or ‘shaped’) to adhere to the ITU-T G.703 pulse template
(shown in
The transmit pulse shaper is bypassed if no MCLK is supplied. In this case, if TCLK is pulled
high then TPOS and TNEG control the pulse width and polarity on TTIP and TRING. With
MCLK supplied and TCLK pulled High, the driver enters TAOS (Transmit All Ones pattern).
The TAOS generator uses MCLK as a timing reference. To ensure that the output frequency
is within specification limits, MCLK must have the applicable stability. TAOS is inhibited
during Remote Loopback.
In the Hardware mode, if TCLK is connected high 16 consecutive MCLK clock cycles and
MCLK is:
When the pulse-shaping circuit is disabled, it is possible to overheat and damage the
LXT384 Transceiver by leaving transmit inputs connected high continuously. For example, if
a programmable ASIC is used in a system that uses the LXT384 Transceiver, the ASIC
outputs might be left high until the ASIC is fully programmed. To prevent damage to the
LXT384
Transceiver, use either one of the following practices:
®
• Not supplied (or ‘low’), the transmit pulse-shaper circuit shown in
• Supplied, the driver enters into a special mode known as Transmit All Ones, or ‘TAOS’.
LXT384 Octal T1/E1/J1 Short-Haul PCM Transceiver with Jitter Attenuation (JA)
(that is, disabled). In this case, TPOS and TNEG control the pulse width and polarity on
TTIP and TRING.
For more information on the TAOS mode, see
Operations
Figure 31
and
Section 8.0,
in
Section 13.0, Mask
Registers.
Specifications).
Section 6.8, Transmit All Ones
TM
TM
Figure 1
6.4 Transmitter
is bypassed
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