lm6172mdr National Semiconductor Corporation, lm6172mdr Datasheet - Page 15

• Manufacturer Part Number: lm6172mdr
• Description: Lm6172qml Dual High Speed, Low Power, Low Distortion, Voltage Feedback Amplifiers
• Manufacturer: National Semiconductor Corporation

placing 0.01μF ceramic capacitors directly to power supply
pins and 2.2μF tantalum capacitors close to the power supply
pins.
TERMINATION
In high frequency applications, reflections occur if signals are
not properly terminated.
signal while
FIGURE 7. Improperly Terminated Signal
FIGURE 6. Properly Terminated Signal
FIGURE 5. Power Supply Bypassing
Figure 7
shows an improperly terminated signal.
Figure 6
shows a properly terminated
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To minimize reflection, coaxial cable with matching charac-
teristic impedance to the signal source should be used. The
other end of the cable should be terminated with the same
value terminator or resistor. For the commonly used cables,
RG59 has 75Ω characteristic impedance, and RG58 has
50Ω characteristic impedance.
POWER DISSIPATION
The maximum power allowed to dissipate in a device is de-
fined as:
Where P
T
T
θ
For example, for the LM6172 in a SO-16 package, the maxi-
mum power dissipation at 25°C ambient temperature is
1000mW.
Thermal resistance, θ
size, package size and package material. The smaller the die
size and package, the higher θ
package has a lower thermal resistance (95°C/W) than that
of 8-pin SO (160°C/W). Therefore, for higher dissipation ca-
pability, use an 8-pin DIP package.
The total power dissipated in a device can be calculated as:
P
connected at the output. P
vice with a load connected at the output; it is not the power
dissipated by the load.
Furthermore,
P
P
For example, the total power dissipated by the LM6172 with
V
into 1kΩ is
P
: =
: =
: =
J(max)
A
JA
Q
Q
L
S
D
: =
:
: =
is the ambient temperature
= ±15V and both channels swinging output voltage of 10V
is the quiescent power dissipated in a device with no load
is the thermal resistance of a particular package
= supply current x total supply voltage with no load
is the maximum junction temperature
D
output current x (voltage difference between supply
voltage and output voltage of the same supply)
P
2[(2.3mA)(30V)] + 2[(10mA)(15V − 10V)]
138mW + 100mW
238mW
is the power dissipation in a device
Q
+ P
L
P
D
JA
= (T
, depends on parameters such as die
P
D
L
J(max)
= P
is the power dissipated in the de-
Q
− T
JA
+ P
becomes. The 8-pin DIP
A
L
)/θ
JA
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