The Analysis Tech Rjc Air Cooled Thermal Test Fixture is a high performance air cooled heat sink with convenient connections to the device-under-test. This air-cooled heat sink fixture is ideally suited for measuring the JEDEC-defined "Rjc" according to MilStd 883 method 1012. Device case temperature is measured by a special type-T spring-loaded thermocouple probe mounted so that only its small Teflon tip protrudes above the plate surface. Once secured to the fixture, the device-under-test compresses the sensor thermocouple for an accurate measurement of the case temperature.

A top-mounted combination plug/screw connector provides high-current heating-power connections to the device-under-test. The side-mounted edge-card connector provides duplicate low-current terminals, convenient for part-specific wiring and kelvin connections. This design allows the fixture to be quickly reconfigured for any part-type by swapping the part-specific, two-connector wiring harness.

The device-under-test is clamped to the heat sink surface with a special pneumatic clamp, shown above. The pneumatic clamp offers a regulated and measured clamping force that will not change with temperature-induced dimensional changes of the sample. The air cylinder used is a special air-balance cylinder with fluidic bearing that provides very accurate force measurement and control. The cooling stage is isolated from ground, therefore devices with a "live" or "hot" connection to the heat sink can easily be tested.

Inexpensive upgrades to existing fixtures are available for the convenience of the latest connector system.

Rjc-Air Performance Specifications:

R_{Heat Sink} = (T_Plate - T _Air) / Power Dissipation = 0.25° C/watt