Datasheet

AD9522-1
Rev. 0 | Page 60 of 84
THERMAL PERFORMANCE
Table 47. Thermal Parameters for the 64-Lead LFCSP
Symbol Thermal Characteristic Using a JEDEC JESD51-7 Plus JEDEC JESD51-5 2S2P Test Board Value (°C/W)
θ
JA
Junction-to-ambient thermal resistance, 0.0 m/sec airflow per JEDEC JESD51-2 (still air) 22.0
θ
JMA
Junction-to-ambient thermal resistance, 1.0 m/sec airflow per JEDEC JESD51-6 (moving air) 19.2
θ
JMA
Junction-to-ambient thermal resistance, 2.0 m/sec airflow per JEDEC JESD51-6 (moving air) 17.2
Ψ
JB
Junction-to-board characterization parameter, 1.0 m/sec airflow per JEDEC JESD51-6 (moving air)
and JEDEC JESD51-8
11.6
θ
JC
Junction-to-case thermal resistance (die-to-heat sink) per MIL-STD-883, Method 1012.1 1.3
Ψ
JT
Junction-to-top-of-package characterization parameter, 0 m/sec airflow per JEDEC JESD51-2 (still air) 0.1
The AD9522 is specified for a case temperature (T
CASE
). To ensure
that T
CASE
is not exceeded, an airflow source can be used.
Use the following equation to determine the junction
temperature on the application PCB:
T
J
= T
CASE
+ (Ψ
JT
× PD)
where:
T
J
is the junction temperature (°C).
T
CASE
is the case temperature (°C) measured by the user at the
top center of the package.
Ψ
JT
is the value from Table 47.
PD is the power dissipation (see the total power dissipation in
Table 18).
Values of θ
JA
are provided for package comparison and PCB
design considerations. θ
JA
can be used for a first-order
approximation of T
J
by the equation
T
J
= T
A
+ (θ
JA
× PD)
where T
A
is the ambient temperature (°C).
Values of θ
JC
are provided for package comparison and PCB
design considerations when an external heat sink is required.
Values of Ψ
JB
are provided for package comparison and PCB
design considerations.