LM675T National Semiconductor, LM675T Datasheet - Page 7

• Manufacturer Part Number: LM675T
• Description: IC, OP-AMP, 5.5MHZ, 8V/µs, TO-220-5
• Manufacturer: National Semiconductor

Specifications of LM675T

• Op Amp Type: Low Offset Voltage
• No. Of Amplifiers: 1
• Bandwidth: 5.5MHz
• Slew Rate: 8V/µs
• Supply Voltage Range: 10V To 60V
• Amplifier Case Style: TO-220
• No. Of Pins: 5
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Application Hints
1.6˚C/W lubricated and 3.4˚C/W dry. For this example, we
assume a lubricated mica insulator between the LM675 and
the heat sink. The heat sink thermal resistance must then be
less than
This is a rather large heat sink and may not be practical in
some applications. If a smaller heat sink is required for
reasons of size or cost, there are two alternatives. The
maximum ambient operating temperature can be restricted
to 50˚C (122˚F), resulting in a 1.6˚C/W heat sink, or the heat
sink can be isolated from the chassis so the mica washer is
not needed. This will change the required heat sink to a
1.2˚C/W unit if the case-to-heat-sink interface is lubricated.
Typical Applications
4.2˚C/W − 2˚C/W − 1.6˚C/W = 0.6˚C/W.
(Continued)
Non-Inverting Unity Gain Operation
Inverting Unity Gain Operation
7
The thermal requirements can become more difficult when
an amplifier is driving a reactive load. For a given magnitude
of load impedance, a higher degree of reactance will cause
a higher level of power dissipation within the amplifier. As a
general rule, the power dissipation of an amplifier driving a
60˚ reactive load will be roughly that of the same amplifier
driving the resistive part of that load. For example, some
reactive loads may at some frequency have an impedance
with a magnitude of 8Ω and a phase angle of 60˚. The real
part of this load will then be 8Ω x cos 60˚ or 4Ω, and the
amplifier power dissipation will roughly follow the curve of
power dissipation with a 4Ω load.
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