Analog Devices AD9912 specifications Thermal Performance, Thermal Parameters

			AD9912
THERMAL PERFORMANCE
Table 7. Thermal Parameters
Symbol	Thermal Characteristic Using a JEDEC51-7 Plus JEDEC51-5 2S2P Test Board	Value		Unit
θJA	Junction-to-ambient thermal resistance, 0.0 m/sec air flow per JEDEC JESD51-2 (still air)	25.2		°C/W
θJMA	Junction-to-ambient thermal resistance, 1.0 m/sec air flow per JEDEC JESD51-6 (moving air)	22.0		°C/W
θJMA	Junction-to-ambient thermal resistance, 2.0 m/sec air flow per JEDEC JESD51-6 (moving air)	19.8		°C/W
θJB	Junction-to-board thermal resistance, 1.0 m/sec air flow per JEDEC JESD51-8 (moving air)	13.9		°C/W
θJC	Junction-to-case thermal resistance (die-to-heat sink) per MIL-Std 883, Method 1012.1	1.7		°C/W
ΨJT	Junction-to-top-of-package characterization parameter, 0 m/sec air flow per JEDEC JESD51-2 (still air)	0.1		°C/W

The AD9912 is specified for a case temperature (TCASE). To ensure that TCASE is not exceeded, an airflow source can be used.

Use the following equation to determine the junction tempera- ture on the application PCB:

TJ = TCASE + (ΨJT × PD)

where:

TJ is the junction temperature (°C).

TCASE is the case temperature (°C) measured by customer at top center of package.

ΨJT is the value from Table 7.

PD is the power dissipation (see the Total Power Dissipation section in the Specifications section).

Values of θJA are provided for package comparison and PCB design considerations. θJA can be used for a first-order approximation of TJ by the equation

TJ = TA + (θJA × PD)

where TA is the ambient temperature (°C).

Values of θJC are provided for package comparison and PCB design considerations when an external heat sink is required.

Values of θJB are provided for package comparison and PCB design considerations.

The values in Table 7 apply to both 64-lead package options.

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