HD404374FT datasheet(122/161 Pages) RENESAS

122 / 161 page

HD404374/HD404384/HD404389/HD404082/HD404084 Series

Rev.5.00, Sep.11.2003, page 122 of 161

PROM Reliability after Programming: In general, semiconductor devices retain their reliability,

provided that some initial defects can be excluded. These initial defects can be detected and rejected by

screening. Baking devices under high-temperature conditions is one method of screening that can rapidly

eliminate data-hold defects in memory cells. (Refer to the previous Principles of Programming/Erasure

section.)

ZTAT™ microcomputer devices are extremely reliable because they have been subjected to such a

screening method during the wafer fabrication process, but Hitachi recommends that each device be

exposed to 150°C at one atmosphere for at least 48 hours after it is programmed, to ensure its best

performance. The recommended screening procedure is shown in figure 74.

Note:

If programming errors occur continuously during PROM programming, suspend programming and

check for problems in the PROM programmer or socket adapter. If programming verification

indicates errors in programming or after high-temperature exposure, please inform Renesas

Technology.

Programming, verification

Exposure to high temperature, without power

150˚C

± 10˚C, 48 h +8h*

−0h

Program read check

VCC = 4.5 V or 5.5 V

Note: * Exposure time is measured from when the temperature in the heater reaches 150˚C.

Figure 74 Recommended Screening Procedure

Programming percentage: Programming percentage is guarenteed to more than 95%.

HD404374FT Datasheet(PDF) 122 Page - Renesas Technology Corp