Datasheet

ADA4899-1
Rev. B | Page 5 of 20
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
Supply Voltage 12.6 V
Power Dissipation See Figure 4
Differential Input Voltage ±1.2 V
Differential Input Current ±10 mA
Storage Temperature Range –65°C to +150°C
Operating Temperature Range –40°C to +125°C
Lead Temperature (Soldering 10 sec) 300°C
Junction Temperature 150°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
MAXIMUM POWER DISSIPATION
The maximum safe power dissipation in the ADA4899-1
package is limited by the associated rise in junction temperature
(T
J
) on the die. The plastic encapsulating the die locally reaches
the junction temperature. At approximately 150°C, which is the
glass transition temperature, the plastic changes its properties.
Even temporarily exceeding this temperature limit may change
the stresses that the package exerts on the die, permanently
shifting the parametric performance of the ADA4899-1.
Exceeding a junction temperature of 150°C for an extended
period can result in changes in silicon devices, potentially
causing failure.
The still-air thermal properties of the package and PCB (θ
JA
),
the ambient temperature (T
A
), and the total power dissipated in
the package (P
D
) determine the junction temperature of the die.
The junction temperature is calculated as
T
J
= T
A
+ (P
D
× θ
JA
)
The power dissipated in the package (P
D
) is the sum of the
quiescent power dissipation and the power dissipated in the
package due to the load drive for all outputs. The quiescent
power is the voltage between the supply pins (V
S
) times the
quiescent current (I
S
). Assuming the load (R
L
) is referenced to
midsupply, the total drive power is V
S
/2 × I
OUT
, some of which is
dissipated in the package and some in the load (V
OUT
× I
OUT
).
The difference between the total drive power and the load
power is the drive power dissipated in the package.
P
D
= Quiescent Power + (Total Drive Power – Load Power)
()
L
OUT
L
OUTS
SS
D
R
V
R
V
V
IVP
2
–
2
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
×+×=
RMS output voltages should be considered. If R
L
is referenced to
V
S
–, as in single-supply operation, the total drive power is V
S
×
I
OUT
. If the rms signal levels are indeterminate, consider the
worst case, when V
OUT
= V
S
/4 for R
L
to midsupply
()
(
)
L
S
SS
D
R
/V
IVP
2
4
+×=
In single-supply operation with R
L
referenced to V
S
–, worst case
is V
OUT
= V
S
/2.
Airflow increases heat dissipation, effectively reducing θ
JA
. In
addition, more metal directly in contact with the package leads
from metal traces, through holes, ground, and power planes
reduces the θ
JA
. Soldering the exposed paddle to the ground
plane significantly reduces the overall thermal resistance of the
package.
Figure 4 shows the maximum safe power dissipation in the
package vs. the ambient temperature for the exposed paddle
(EPAD) 8-lead SOIC (70°C/W) and 8-lead LFCSP (70°C/W)
packages on a JEDEC standard 4-layer board. θ
JA
values are
approximations.
05720-003
AMBIENT TEMPERATURE (°C)
120–40–200 20406080100
MAXIMUM POWER DISSIPATION (W)
0.0
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
LFCSP AND SOIC
Figure 4. Maximum Power Dissipation vs. Ambient Temperature
ESD CAUTION