LM124/LM224/LM324/LM2902
Application Hints
(Continued)
The bias network of the LM124 establishes a drain current
which is independent of the magnitude of the power supply
voltage over the range of from 3 V
DC
to 30 V
DC
.
Output short circuits either to ground or to the positive power
supply should be of short time duration. Units can be de-
stroyed, not as a result of the short circuit current causing
metal fusing, but rather due to the large increase in IC chip
dissipation which will cause eventual failure due to exces-
sive junction temperatures. Putting direct short-circuits on
more than one amplifier at a time will increase the total IC
power dissipation to destructive levels, if not properly pro-
tected with external dissipation limiting resistors in series
with the output leads of the amplifiers. The larger value of
output source current which is available at 25˚C provides a
larger output current capability at elevated temperatures
(see typical performance characteristics) than a standard IC
op amp.
The circuits presented in the section on typical applications
emphasize operation on only a single power supply voltage.
If complementary power supplies are available, all of the
standard op amp circuits can be used. In general, introduc-
ing a pseudo-ground (a bias voltage reference of V
+
/2) will
allow operation above and below this value in single power
supply systems. Many application circuits are shown which
take advantage of the wide input common-mode voltage
range which includes ground. In most cases, input biasing is
not required and input voltages which range to ground can
easily be accommodated.
(V
+
= 5.0 V
DC
)
Typical Single-Supply Applications
Non-Inverting DC Gain (0V Input = 0V Output)
00929905
*R not needed due to temperature independent I
IN
DC Summing Amplifier
(V
IN’S
≥
0 V
DC
and V
O
≥
V
DC
)
Power Amplifier
00929906
00929907
Where: V
0
= V
1
+ V
2
− V
3
− V
4
(V
1
+ V
2
)
≥
(V
3
+ V
4
) to keep V
O
>
0 V
DC
V
0
= 0 V
DC
for V
IN
= 0 V
DC
A
V
= 10
9
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