7.4 Thermal Information
see (1)THERMAL METRIC(2) | TLK2711-SP | UNIT |
HFG (CFP) |
68 PINS |
RθJA |
Junction-to-ambient thermal resistance |
31.5 |
°C/W |
RθJC |
Junction-to-case thermal resistance |
2.96 |
°C/W |
(1) This CFP package has built-in vias that electrically and thermally connect the bottom of the die to a pad on the bottom of the package. To efficiently remove heat and provide a low-impedance ground path, a thermal land is required on the surface of the PCB directly underneath the body of the package. During normal surface mount flow solder operations, the heat pad on the underside of the package is soldered to this thermal land creating an efficient thermal path. Normally, the PCB thermal land has a number of thermal vias within it that provide a thermal path to internal copper areas (or to the opposite side of the PCB) that provide for more efficient heat removal. TI typically recommends an 11.9-mm × 11.9-mm board-mount thermal pad with a 4.2-mm × 4.2-mm solder mask defined pad attach opening. This allows maximum area for thermal dissipation, while allowing leads pad to solder pad clearance. A sufficient quantity of thermal or electrical vias must be included to keep the device within Recommended Operating Conditions. This pad must be electrically ground potential.
(2) For more information about traditional and new thermal metrics, see the
Semiconductor and IC Package Thermal Metrics application report,
SPRA953.