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TI486 Microprocessor - Al Kossow's Bitsavers

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Thermal Characteristics<br />

6.3 Thermal Characteristics<br />

The <strong>TI486</strong>SLC/E is designed to operate when the case temperature is<br />

between aoc and 1 aaoc. The <strong>TI486</strong>SLC/E-V, <strong>TI486</strong>DLC/E and <strong>TI486</strong>DLC/E-V<br />

are designed to operate when the case temperature is between aoc and 85°C.<br />

The case temperatures are measured on the top center of the package. The<br />

maximum die temperature (Tjmax) and the maximum ambient temperature<br />

(Tamax) can be calculated using the following equations.<br />

where:<br />

Tjmax = Tc + (Pmax x ejd<br />

Tamax = Tj - (Pmax x eja)<br />

Tjmax = Maximum average junction temperature (OC)<br />

Tc = Case temperature at top center of package (OC)<br />

P max = Maximum device power dissipation (W)<br />

ejc = Junction-to-case thermal resistance (OC/W)<br />

Tamax = Maximum ambient temperature (OC)<br />

Tj = Average junction temperature (OC)<br />

eja = Junction-to-ambient thermal resistance (OC/W)<br />

Values for eja and ejc are given in Table 6-5 for various airflows.<br />

Table 6-5. Package Thermal Resistance and Airflow<br />

THERMAL RESISTANCE (OCIW)<br />

AIRFLOW 100-LEAD 132-PIN CERAMIC<br />

(FT/SEC) PLASTIC BQFP PGAPACKAGE<br />

Sja Sjc Sja Sjc<br />

0 21 2 20 3<br />

100 19 2 18 3<br />

250 16 2 14 3<br />

500 13 2 10 3<br />

6-11

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