Woodruff, Richard wrote:

...

I hope you don't solder your chips on the board, cause bad blocks can

be

...

present in pristine chips fresh from the factory. This will NOT work, since a bad block anywhere in the range that you

use

...

means that you must replace the chip.

Bad blocks can in practice be a bit harder to get then one might think. In say ... 500 different samples which passed my desk in the last three years none of them actually had bad blocks. They could have of coarse. We simulated bad blocks. It is a real problem.

I thought it was rare too until I got one chip with a bad block just the other day.

It seems to vary with the lot.

Regards,

Richard W.

Regards

Pantelis