DM385, DM388
SPRS821D –MARCH 2013–REVISED DECEMBER 2013
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8 Peripheral Information and Timings
8.1 Parameter Information
Tester Pin Electronics
Data Sheet Timing Reference Point
42 Ω
3.5 nH
Output
Under
Test
Transmission Line
Z0 = 50 Ω
(see Note)
Device Pin
(see Note)
4.0 pF
1.85 pF
NOTE: The data sheet provides timing at the device pin. For output timing analysis, the tester pin electronics and its transmission line effects must be
taken into account.Atransmission line with a delay of 2 ns can be used to produce the desired transmission line effect. The transmission line is
intended as a load only. It is not necessary to add or subtract the transmission line delay (2 ns) from the data sheet timings.
Input requirements in this data sheet are tested with an input slew rate of < 4 Volts per nanosecond (4 V/ns) at the device pin.
Figure 8-1. Test Load Circuit for AC Timing Measurements
The load capacitance value stated is only for characterization and measurement of AC timing signals. This
load capacitance value does not indicate the maximum load the device is capable of driving.
8.1.1 1.8-V and 3.3-V Signal Transition Levels
All input and output timing parameters are referenced to Vref for both "0" and "1" logic levels. For 3.3-V I/O,
Vref = 1.5 V. For 1.8-V I/O, Vref = 0.9 V.
Vref
Figure 8-2. Input and Output Voltage Reference Levels for AC Timing Measurements
All rise and fall transition timing parameters are referenced to VIL MAX and VIH MIN for input clocks, VOL
MAX and VOH MIN for output clocks.
Vref = VIH MIN (or VOH MIN)
Vref = VIL MAX (or VOL MAX)
Figure 8-3. Rise and Fall Transition Time Voltage Reference Levels
8.1.2 3.3-V Signal Transition Rates
All timings are tested with an input edge rate of 4 volts per nanosecond (4 V/ns).
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Peripheral Information and Timings
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