SN65LVDS179 tSK(PP) Information

Hi Joe,

Unfortunately, it looks like we don't have any data recorded on the part-to-part skew.  To get a very conservative estimate, you can take a look at the propagation delay specs for the driver and receiver.  Any device produced should have a propagation delay within the spec range, so the maximum possible skew should correspond to the maximum propagation delay spec.

For a less conservative approach, you can take a look at Figure 13 through 16 in the "Typical Characteristics" section of the datasheet.  These curves plot the propagation delays for a typical device across temperature for various supply voltages.  The maximum values in the "Switching Characteristics" table account for temperature variation, power supply variation, and process variation; the "Typical Characteristics" plots only account for voltage and temperature.  If you subtract them, you can get a rough idea of how much the maximum spec is increased due to process.

For example, the highest "typical" driver propagation delay occurs with a 3-V supply and maximum free-air temperature.  Its value is ~2.05 ns.  The maximum spec for this parameter is 2.7 ns, which means that there is a 0.65 ns increase when process variation is considered.  Assuming that the variance due to process shift is symmetrical (i.e., equal variance for both "weak" and "strong" process corners), the total part-to-part skew would be 2 * 0.65 ns = 1.3 ns.  A similar calculation could be done for the receiver, and would yield ~0.9 ns.

Note that these results are "hand-wave" estimates, not guaranteed specs.  Given the device's age (it was released 14 years ago), the original pre-release characterization data is very difficult to come by.

Regards,
Max Robertson
Analog Applications Engineer
Texas Instruments
m-robertson@ti.com