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.
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 VDC to 30 VDC
.
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.
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
Typical Single-Supply Applications (V+ = 5.0 VDC
)
Non-Inverting DC Gain (0V Input = 0V Output)
00929905
*R not needed due to temperature independent I
IN
DC Summing Amplifier
(VIN’S ≥ 0 VDC and VO ≥ VDC
)
Power Amplifier
00929907
00929906
V
= 0 V
for V = 0 V
DC IN DC
0
Where: V = V + V − V − V
4
0
1
2
3
A
= 10
V
>
(V + V ) ≥ (V + V ) to keep V
0 V
DC
1
2
3
4
O
9
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