Data Sheet ADA4850-1/ADA4850-2
Rev. D | Page 5 of 14
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
Supply Voltage 12.6 V
Power Dissipation See Figure 4
Power Down Pin Voltage (−V
S
+ 6) V
Common-Mode Input Voltage Range (−V
S
− 0.5 ) V to (+V
S
+ 0.5) V
Differential Input Voltage Range +V
S
to −V
S
Storage Temperature Range −65°C to +125°C
Operating Temperature Range −40°C to +125°C
(Soldering 10 sec)
Junction Temperature 150°C
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
THERMAL RESISTANCE
θ
JA
is specified for the worst-case conditions, that is, θ
JA
is specified
for the device soldered in the circuit board for surface-mount
packages.
Table 4.
Package Type θ
JA
Unit
8-Lead LFCSP 80 °C/W
Maximum Power Dissipation
The maximum safe power dissipation for the ADA4850-1/
ADA4850-2 is limited by the associated rise in junction
temperature (T
J
) on the die. 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
ADA4850-1/ADA4850-2. Exceeding a junction temperature
of 150°C for an extended period of time can result in changes
in silicon devices, potentially causing degradation or loss of
functionality.
The power dissipated in the package (P
D
) is the sum of the
quiescent power dissipation and the power dissipated in the die
due to the ADA4850-1/ADA4850-2 drive at the output. The
quiescent power is the voltage between the supply pins (V
S
)
times the quiescent current (I
S
).
P
D
= Quiescent Power + (Total Drive Power − Load Power)
( )
L
OUT
L
OUTS
SS
D
R
V
R
V
V
IVP
2
2
−
×+×=
Consider rms output voltages. 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
4V
I
VP
2
/
+
×=
In single-supply operation with R
L
referenced to −V
S
, the 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
and exposed paddle from metal traces through holes, ground,
and power planes reduce θ
JA
.
Figure 4 shows the maximum safe power dissipation in the
package vs. the ambient temperature for the LFCSP (91°C/W)
package on a JEDEC standard 4-layer board. θ
JA
values are
approximations.
Figure 4. Maximum Power Dissipation vs. Temperature for a 4-Layer Board
ESD CAUTION
–55 125–45 –35 –25 –15 –5 5 15 25 35 45 55 65 75 85 95 105 115
MAXIMUM POWER DISSIPATION (W)
AMBIENT TEMPERATURE (°C)
05320-055
0
3.0
2.5
2.0
1.5
1.0
0.5
LFCSP-8
LFCSP-16
T
J
= 150°C
