Reliability Of Programmed Data - Renesas H8 Series Hardware Manual

Section 6 ROM
6.4

Reliability of Programmed Data

A highly effective way to improve data retention characteristics is to bake the programmed chips
at 150°C, then screen them for data errors. This procedure quickly eliminates chips with PROM
memory cells prone to early failure.
Figure 6.6 shows the recommended screening procedure.
Program chip and verify
programmed data
Bake chip for 24 to 48 hours at
125°C to 150°C with power off
Read and check program
Install
Figure 6.6 Recommended Screening Procedure
If a series of programming errors occurs while the same PROM programmer is in use, stop
programming and check the PROM programmer and socket adapter for defects. Please inform
Renesas Technology of any abnormal conditions noted during or after programming or in
screening of program data after high-temperature baking.
Rev. 7.00 Mar 10, 2005 page 153 of 652
REJ09B0042-0700