2 Definition of Terms

The following table provides the definition of terms and the technological data that are used in the following sections. Note that the technological data are different for Automotive and Industrial or Extended Industrial devices.

Table 2-1. Definition of Terms(1)
SymbolDefinitions
Generic
TJDevice junction temperature
VDDVDDCPU voltage
User Mission Profile Data
MPUser Mission Profile: a set of operating points (TJ,VDD)
PoHMP_TARGETUser Power-on Hours target with MP mission profile. This is the total time when the device is powered.
U%Percentage of time spent in each MP operating point
PoH(TJ)Power-on Hours spent at TJ. PoH (TJ) = PoHMP_TARGET x U%

Technological Data

See Figure 3-1 and Table 3-2 for Industrial devices

and Figure 4-1 and Table 4-2 for Automotive devices

PoHQ(TJ,VDD)
Qualified equivalent hours at TJ, VDD, in particular PoHQ(125°C,1.15V) =
  • 29576 for Industrial tier
  • 5733 for Automotive tier
DR(TJ)

Temperature-derating ratio at TJ : PoH[Q](TJ,VDD) = DR(TJ) x PoH[Q](125°C, VDD)

See Table 3-2 and Table 4-2.

VAF

Voltage Acceleration Factor

PoH[Q](TJ, VDD) = VAF x PoH[Q](TJ, 1.15V)

  • VAF = 2.72 for VDD = 1.05V operation
  • VAF = 1.00 for VDD = 1.15V operation
  • VAF = 0.368 for VDD = 1.25V operation
Calculated Quantities
PoHMP(125°C, 1.15V)

Mission profile equivalent Power-on Hours at one point (125°C, 1.15V):

PoH(125°C, 1.15V) = PoH(TJ) / (VAF.DR(TJ))

If this number exceeds PoHQ(125°C, 1.15V) then the mission profile MP is more demanding than the HTOL test.
PoHMP_EST

Estimated Power-on Hours with given MP:

PoHMP_EST = PoHMP_TARGET x PoHQ(125°C, 1.15V) / PoHMP(125°C, 1.15V)

Note:
  1. In the above table, PoH[Q](TJ, VDD) means either PoH(TJ, VDD) or PoHQ(TJ, VDD).