AT89C51RD2 / AT89C51ED2 QualPack

16

Rev. 0 – 2003 July

4.3.4.3 Cell Read Disturb

Purpose:

To measure read disturb influence on 56k8 memory cell.

Test parameters:

Lot:

0t0348

Programming: 14V on WL and sensegate @5ms

Temperature: 25°C and 140°C

The cell is stressed with BL voltage much higher than standard read conditions (around 6V) to accelerate disturb

phenomenon : electrons from the Floating gate can move through the tunnel oxide. This charge loss is measured

after stress by a Vt measurement.

Test results:

Conclusion:

Extrapolation to 10 years lifetime give a maximum BL voltage of around 4V in read operation, which is much higher

than nominal BL read voltage (~1V). So there is no sensitivity to read disturb either at room temperature or high

temperature.

0t0348 #01

56.8k (568A6)

BL read disturb @140C

0

0.5

1

1.5

2

2.5

0.1

1

10

100

1000

10000

Time (s)

Vbl=6V

Vbl=6.5V

Vbl=7V

Vbl=7.5V

Vbl=8V

0t0348 #01

56.8k (568A6)

BL read disturb @25C

0

0.5

1

1.5

2

2.5

0.1

1

10

100

1000

10000

Time (s)

Vbl=6V

Vbl=6.5V

Vbl=7V

Vbl=7.5V

Vbl=8V