64Mb: x4, x8, x16 SDRAM
Temperature and Thermal Impedance
Temperature and Thermal Impedance
It is imperative that the SDRAM device’s temperature specifications, shown in Temper-
ature Limits below, be maintained to ensure the junction temperature is in the proper
operating range to meet data sheet specifications. An important step in maintaining the
proper junction temperature is using the device’s thermal impedances correctly. The
thermal impedances are listed in Table 6 (page 17) for the applicable die revision and
packages being made available. These thermal impedance values vary according to the
density, package, and particular design used for each device.
Incorrectly using thermal impedances can produce significant errors. Read Micron
technical note TN-00-08, “Thermal Applications” prior to using the thermal impedan-
ces listed in Table 6 (page 17). To ensure the compatibility of current and future de-
signs, contact Micron Applications Engineering to confirm thermal impedance values.
The SDRAM device’s safe junction temperature range can be maintained when the TC
specification is not exceeded. In applications where the device’s ambient temperature
is too high, use of forced air and/or heat sinks may be required to satisfy the case tem-
perature specifications.
Table 5: Temperature Limits
Parameter
Symbol
Min
0
Max
80
Unit
Notes
Operating case temperature
Commercial
Industrial
TC
°C
1, 2, 3, 4
–40
–40
0
90
Automotive
Commercial
Industrial
105
85
Junction temperature
Ambient temperature
TJ
°C
°C
°C
3
–40
–40
0
95
Automotive
Commercial
Industrial
110
70
TA
3, 5
–40
–40
–
85
Automotive
105
260
Peak reflow temperature
Notes:
TPEAK
1. MAX operating case temperature, TC, is measured in the center of the package on the
top side of the device, as shown in Figure 8 (page 17), and Figure 9 (page 18).
2. Device functionality is not guaranteed if the device exceeds maximum TC during opera-
tion.
3. All temperature specifications must be satisfied.
4. The case temperature should be measured by gluing a thermocouple to the top-center
of the component. This should be done with a 1mm bead of conductive epoxy, as de-
fined by the JEDEC EIA/JESD51 standards. Take care to ensure that the thermocouple
bead is touching the case.
5. Operating ambient temperature surrounding the package.
PDF: 09005aef80725c0b
64mb_x4x8x16_sdram.pdf - Rev. U 05/13 EN
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