AT89C51RD2 / AT89C51ED2 QualPack

Rev. 0 – 2003 July

15

Conclusions:

-

Vt_wrt shift of 200 mV after 10k cycles

-

I_read decrease of 2.5 uA after 10kcycles (- 7 to 9 %)

-

No big difference between bit0 and bit 7 in terms of Vt or current variations Using the coefficients

4.3.4.2 Cell retention

Purpose:

To extrapolate cell life duration at 125°C from bake measurements at high temperature.

Test parameters:

Lot:

9T0930

Temperature: 250°C and 200°C

Duration:

92 hours

Lifetime Prediction:

The equation used to describe memory cell retention is:

DVt (V) = A * (t[h])^m * exp (-1.05eV/kT[K])

Results :

56.8k cell - 9t0930 (#24/25)

y = 0,2138Ln(x) - 2,3118

y = 0,2211Ln(x) - 4,8026

-5

-4

-3

-2

-1

0

1

10

100

Bake time (h)

200C

250C

150,0

170,0

190,0

210,0

230,0

250,0

270,0

290,0

1

10

100

1000

10000

100000

time (h)

Test measurements

Extrapolated Life Time

Conclusions :

Extrapolation to 125°C - 10years = Vt loss is less than 0.8 mV