Datasheet

4kT=1.6x10 J
at290K
-20
4kT
V
RF
= 4kTR
F
Ö
OPA4872
e
n
i
ni
i
in
R
S
V
RS
= 4kTR
S
Ö
R
G
e
o
R
F
i
RG
R
G
Ö
OPA4872
www.ti.com SBOS346C –JUNE 2007–REVISED MARCH 2011
THERMAL ANALYSIS
load power. Quiescent power is simply the specified
no-load supply current times the total supply voltage
Heatsinking or forced airflow may be required under
across the part. P
DL
depends on the required output
extreme operating conditions. Maximum desired
signal and load; for a grounded resistive load, P
DL
is
junction temperature sets the maximum allowed
at a maximum when the output is fixed at a voltage
internal power dissipation as discussed in this
equal to 1/2 of either supply voltage (for equal bipolar
document. In no case should the maximum junction
supplies). Under this condition P
DL
= V
S
2
/(4 × R
L
),
temperature be allowed to exceed +150°C.
where R
L
includes feedback network loading.
Operating junction temperature (T
J
) is given by T
A
+
Note that it is the power in the output stage and not in
P
D
× θ
JA
. The total internal power dissipation (P
D
) is
the load that determines internal power dissipation.
the sum of quiescent power (P
DQ
) and additional
power dissipated in the output stage (P
DL
) to deliver
Figure 35. OPA4872 Noise Analysis Model
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