EL5211A Просмотр технического описания (PDF) - Intersil
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EL5211A Datasheet PDF : 11 Pages
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EL5211A
continuous current never exceeds ±65mA. This limit is set by
the design of the internal metal interconnects.
Output Phase Reversal
The EL5211A is immune to phase reversal as long as the
input voltage is limited from VS- -0.5V to VS+ +0.5V. Figure
28 shows a photo of the output of the device with the input
voltage driven beyond the supply rails. Although the device's
output will not change phase, the input's overvoltage should
be avoided. If an input voltage exceeds supply voltage by
more than 0.6V, electrostatic protection diodes placed in the
input stage of the device begin to conduct and overvoltage
damage could occur.
1V
10µs
VS=±2.5V
TA=25°C
AV=1
1V
VIN=6VP-P
FIGURE 28. OPERATION WITH BEYOND-THE-RAILS INPUT
Power Dissipation
With the high-output drive capability of the EL5211A
amplifier, it is possible to exceed the 125°C 'absolute-
maximum junction temperature' under certain load current
conditions. Therefore, it is important to calculate the
maximum junction temperature for the application to
determine if load conditions need to be modified for the
amplifier to remain in the safe operating area.
The maximum power dissipation allowed in a package is
determined according to:
PDMAX
=
T----J---M-----A----X-----–-----T----A---M-----A----X--
ΘJA
where:
• TJMAX = Maximum junction temperature
• TAMAX = Maximum ambient temperature
• ΘJA = Thermal resistance of the package
• PDMAX = Maximum power dissipation in the package
The maximum power dissipation actually produced by an IC
is the total quiescent supply current times the total power
supply voltage, plus the power in the IC due to the loads, or:
PDMAX = Σi[VS × ISMAX + (VS+ – VOUTi ) × ILOADi ]
when sourcing, and:
PDMAX = Σi[VS × ISMAX + (VOUTi – VS- ) × ILOADi ]
when sinking,
where:
• i = 1 to 2 for dual and 1 to 4 for quad
• VS = Total supply voltage
• ISMAX = Maximum supply current per amplifier
• VOUTi = Maximum output voltage of the application
• ILOADi = Load current
If we set the two PDMAX equations equal to each other, we
can solve for RLOADi to avoid device overheat. Figures 29
and 30 provide a convenient way to see if the device will
overheat. The maximum safe power dissipation can be
found graphically, based on the package type and the
ambient temperature. By using the previous equation, it is a
simple matter to see if PDMAX exceeds the device's power
derating curves. To ensure proper operation, it is important
to observe the recommended derating curves shown in
Figures 29 and 30.
JEDEC JESD51-3 LOW EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
0.6
0.5 486mW
0.4
0.3
θJA =2H0M6S°CO/WP8
0.2
0.1
0
0
25
50
75 85 100
125
AMBIENT TEMPERATURE (°C)
FIGURE 29. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
JEDEC JESD51-7 HIGH EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
1
0.9 870mW
0.8
0.7
0.6
0.5
θJA =1H1M5°SCO/WP8
0.4
0.3
0.2
0.1
0
0
25
50
75 85 100
125
AMBIENT TEMPERATURE (°C)
FIGURE 30. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
10
FN6143.0
June 15, 2005
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