7.6 T_{ON (VDD)} and T_{OFF (VDD)} Time

T_{ON (VDD)} time is defined as the time taken by the output of the device to rise to 90% after the supply has risen past the supply threshold. The 90% measurement is utilized to provide the timing of the device turning on in the system. The time constant from the load resistance and load capacitance can be added to the turn-on-VDD time to calculate system level timing. Figure 32 shows the setup used to measure transition time, denoted by the symbol t_{ON (VDD)}.

T_{OFF (VDD)} time is defined as the time taken by the output of the device to fall to 90% after the enable has fallen past the supply threshold. The 90% measurement is utilized to provide the timing of the device turning off in the system. The time constant from the load resistance and load capacitance can be added to the turn-off-VDD time to calculate system level timing. Figure 32 shows the setup used to measure transition time, denoted by the symbol t_{OFF (VDD)}.

Figure 32. Turn-On-VDD and Turn-Off-VDD Time Measurement Setup