22
TS8308500
2193A–BDC–04/03
TS8308500
Main Features
Timing
Information
Timing Value for
TS8308500
Timing values as defined in Table 3 on page 4 are advanced data, issuing from electric simu-
lations and are the first characterization results fitted with measurements.
Timing values are given for CBGA68 package inputs/outputs, taking into account package
internal controlled impedance traces propagation delays, and specified termination loads.
Propagation delays in 50/75
impedance traces are NOT taken into account for TOD and
TDR.
Apply proper derating values corresponding to termination topology.
The min/max timing values are valid over the full temperature range in the following
conditions:
–
Specified termination load (differential output Data and Data Ready):
50
resistor in parallel with 1 standard ECLinPS register from Motorola, (i.e.:
10E452). (Typical ECLinPS inputs shows a typical input capacitance of 1.5 pF
(including package and ESD protections). If addressing an output Dmux, take care
if some Digital outputs do not have the same termination load and apply
corresponding derating value given below
–
Output Termination Load derating values for TOD and TDR:
~ 35 ps/pF or 50 ps per additional ECLinPS load
–
Propagation time delay derating values have also to be applied for TOD and TDR:
~ 6 ps/mm (155 ps/inch) for TSEV8308500 Evaluation Board
Apply proper time delay derating value if a different dielectric layer is used.
Propagation Time
Considerations
TOD and TDR timing values are given from pin to pin and DO NOT include the additional
propagation times between device pins and input/output termination loads. For the
TSEV8308500 Evaluation Board, the propagation time delay is 6 ps/mm (155 ps/inch) corre-
sponding to 3.4 (at 10 GHz) dielectric constant of the RO4003 used for the Board.
If a different dielectric layer is used (for instance Teflon), use appropriate propagation time
values.
TD does NOT depend on propagation times because it is a differential data.
(TD is the time difference between Data Ready output delay and digital Data output delay)
TD is also the most straightforward data to measure, again because it is differential: TD can be
measured directly onto termination loads, with matched oscilloscopes probes.
TOD-TDR Variation
Over Temperature
Values for TOD and TDR track each other over temperature (1% variation for TOD-TDR per
100
°C temperature variation).
Therefore TOD-TDR variation over temperature is negligible. Moreover, the internal (on-chip)
and package skews between each Data TODs and TDR affect can be considered as
negligible.