HX6228

3

Total Dose

rad(SiO

Transient Dose Rate Upset (3)

rad(Si)/s

Transient Dose Rate Survivability

rad(Si)/s

Soft Error Rate

upsets/bit-day

Neutron Fluence

Parameter

Limits (2)

Test Conditions

RADIATION HARDNESS RATINGS (1)

The SRAM will meet any functional or electrical specifica-

tion after exposure to a radiation pulse up to the transient

dose survivability specification,when applied under recom-

mended operating conditions. Note that the current con-

ducted during the pulse by the RAM inputs, outputs, and

power supply may significantly exceed the normal operat-

ing levels. The application design must accommodate

these effects.

Neutron Radiation

The SRAM will meet any functional or timing specification

after exposure to the specified neutron fluence under

recommended operating or storage conditions. This as-

sumes an equivalent neutron energy of 1 MeV.

Soft Error Rate

The SRAM is capable of meeting the specified Soft Error

Rate (SER), under recommended operating conditions.

This hardness level is defined by the Adams 90% worst

case cosmic ray environment for geosynchronous orbits.

Latchup

The SRAM will not latch up due to any of the above radiation

exposure conditions when applied under recommended

operating conditions. Fabrication with the SIMOX sub-

strate material provides oxide isolation between adjacent

PMOS and NMOS transistors and eliminates any potential

SCR latchup structures. Sufficient transistor body tie con-

nections to the p- and n-channel substrates are made to

ensure no source/drain snapback occurs.

Total Ionizing Radiation Dose

The SRAM will meet all stated functional and electrical

specifications over the entire operating temperature range

after the specified total ionizing radiation dose. All electrical

and timing performance parameters will remain within

specifications after rebound at VDD = 5.5 V and T =125

°C

extrapolated to ten years of operation. Total dose hardness

is assured by wafer level testing of process monitor transis-

tors and RAM product using 10 KeV X-ray and Co60

radiation sources. Transistor gate threshold shift correla-

tions have been made between 10 KeV X-rays applied at

rays (Cobalt 60 source) to ensure that wafer level X-ray

testing is consistent with standard military radiation test

environments.

Transient Pulse Ionizing Radiation

The SRAM is capable of writing, reading, and retaining

stored data during and after exposure to a transient ionizing

radiation pulse up to the specified transient dost rate upset

specification, when applied under recommended operat-

ing conditions. To ensure validity of all specified perfor-

mance parameters before, during, and after radiation (tim-

ing degradation during transient pulse radiation is

≤20%),

it is suggested that stiffening capacitance be placed on or

near the package VDD and VSS, with a maximum induc-

tance between the package (chip) and stiffening capaci-

tance of 0.7 nH per part. If there are no operate-through or

valid stored data requirements, typical circuit board

mounted de-coupling capacitors are recommended.

Units

(1) Device will not latch up due to any of the specified radiation exposure conditions.

(2) Operating conditions (unless otherwise specified): VDD=4.5 V to 5.5 V, -55

°C to 125°C.

(3) Applies to 40-lead flat pack only. Assume

dose rate upset performance as stated above.

°C, Adams 90%

worst case environment

Pulse width

≤50 ns, X-ray,

°C

Pulse width

≤1 µs

°C

1 MeV equivalent energy,

°C

RADIATION CHARACTERISTICS