DS125RT410_15 Datasheet, PDF (18/58 Pages) Texas Instruments – Low-Power Multi-Rate Quad Channel Retimer

DS125RT410
SNLS459A – APRIL 2013 – REVISED OCTOBER 2015
www.ti.com
7.4.4.6 Driver Output De-Emphasis
The output de-emphasis level of the DS125RT410 can be configured from a nominal setting of 0 dB to a nominal
setting of –15 dB depending upon the application. Larger absolute values of the de-emphasis setting provide
more pre-distortion of the output driver waveform, accentuating the high-frequency components of the output
driver waveform relative to the low-frequency components. Greater values of de-emphasis can compensate for
greater dispersion in the transmission media at the output of the DS125RT410. The output de-emphasis level as
set is the typical value to which the output signal will settle following the de-emphasis pulse interval in dB relative
to the output VOD.
7.4.4.7 Driver Output Rise and Fall Time
In some applications, a longer rise and fall time for the output signal is desired. This can reduce electromagnetic
interference (EMI) generated by fast switching waveforms. This is necessary in some applications for regulatory
compliance. In others, it can reduce the crosstalk in the system.
The DS125RT410 can be configured to operate with a nominal rise and fall time corresponding to the maximum
slew rate of the output drivers into the load capacitance. Alternatively, the DS125RT410 can be configured to
operate with a slightly greater rise and fall time if desired. For the typical specifications on rise and fall time, see
Electrical Characteristics.
7.4.4.8 INT
The INT line is an open-drain, 3.3-V tolerant, LVCMOS active-low output. The INT lines from multiple
DS125RT410 devices can be wired together and connected to an external controller.
The horizontal eye opening/vertical eye opening (HEO/VEO) interrupt can be enabled using SMBus control for
each channel independently. This interrupt is disabled by default. The thresholds for horizontal and vertical eye
opening that will trigger the interrupt can be set using the SMBus control for each channel.
If any interrupt occurs, registers in the DS125RT410 latch in information about the event that caused the
interrupt. This can then be read out by the controller over the SMBus.
7.4.4.9 LOCK_3, LOCK_2, LOCK_1, and LOCK_0
Each channel of the DS125RT410 has an independent lock indication pin. These lock indication pins, LOCK_3,
LOCK_2, LOCK_1, and LOCK_0, are pin 16, pin 21, pin 40, and pin 45 respectively. These pins are shared with
the SMBus address strap lines. After the address values have been latched in on power-up, these lines revert to
their lock indication function.
When the corresponding channel of the DS125RT410 is locked to the incoming data stream, the lock indication
pin goes high. This pin can be used to drive an LED on the board, giving a visual indication of the lock status, or
it can be connected to other circuitry that can interpret the lock status of the channel.
18
Submit Documentation Feedback
Copyright © 2013–2015, Texas Instruments Incorporated
Product Folder Links: DS125RT410