AD9912
Rev. D | Page 23 of 40
THERMAL PERFORMANCE
Table 7. Thermal Parameters
Symbol
Thermal Characteristic Using a JEDEC51-7 Plus JEDEC51-5 2S2P Test Board
Value
Unit
θ
JA
Junction-to-ambient thermal resistance, 0.0 m/sec air flow per JEDEC JESD51-2 (still air)
25.2
°C/W
θ
JMA
Junction-to-ambient thermal resistance, 1.0 m/sec air flow per JEDEC JESD51-6 (moving air)
22.0
°C/W
θ
JMA
Junction-to-ambient thermal resistance, 2.0 m/sec air flow per JEDEC JESD51-6 (moving air)
19.8
°C/W
θ
JB
Junction-to-board thermal resistance, 1.0 m/sec air flow per JEDEC JESD51-8 (moving air)
13.9
°C/W
θ
JC
Junction-to-case thermal resistance (die-to-heat sink) per MIL-Std 883, Method 1012.1
1.7
°C/W
Ψ
JT
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 (T
CASE
). To
ensure that T
CASE
is not exceeded, an airflow source can be used.
Use the following equation to determine the junction tempera-
ture 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 customer at top
center of package.
Ψ
JT
is the value from Table 7.
PD
is the power dissipation (see the Total Power Dissipation
section in the Specifications section).
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 θ
JB
are provided for package comparison and PCB
design considerations.
The values in Table 7 apply to both 64-lead package options.