t
AVAV
A(14:0)
CE
t
ELQX
t
ELQV
OE
t
GLQV
DQ(7:0)
t
GLQX
t
AVQV
t
AXQX
t
GHQZ
t
AVQV
t
EHQZ
Figure 2. PROM Read Cycle
RADIATION HARDNESS
The UT28F256 PROM incorporates special design and layout
features which allow operation in high-level radiation
environments. UTMC has developed special low-temperature
processing techniques designed to enhance the total-dose
radiation hardness of both the gate oxide and the field oxide while
RADIATION HARDNESS DESIGN SPECIFICATIONS
1
Total Dose
Latchup LET Threshold
Memory Cell LET Threshold
Transient Upset LET Threshold
Transient Upset Device Cross Section @ LET=128 MeV-cm
2
/mg
maintaining the circuit density and reliability. For transient
radiation hardness and latchup immunity, UTMC builds all
radiation-hardened products on epitaxial wafers using an
advanced twin-tub CMOS process. In addition, UTMC pays
special attention to power and ground distribution during the
design phase, minimizing dose-rate upset caused by rail collapse.
1E6
>128
>128
54
1E-6
rad(Si)
MeV-cm
2
/mg
MeV-cm
2
/mg
MeV-cm
2
/mg
cm
2
Note:
1 . The PROM will not latchup during radiation exposure under recommended operating conditions.
5
AEROFLEX [ AEROFLEX CIRCUIT TECHNOLOGY ]
