EL5221CY(2005) View Datasheet(PDF) - Intersil
Part Name
Description
MFG CO.
EL5221CY Datasheet PDF : 11 Pages
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EL5221
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
VIN=6VP-P
1V
FIGURE 2. OPERATION WITH BEYOND-THE-RAILS INPUT
Power Dissipation
With the high-output drive capability of the EL5221 buffer, 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 buffer 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 buffer
VS = Total supply voltage
ISMAX = Maximum supply current per channel
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. Figure 3 and
Figure 4 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
Figure 3 and Figure 4.
Package Mounted on a JEDEC JESD51-7 High
Effective Thermal Conductivity Test Board
1
870mW
MAX TJ=125°C
0.8
0.6
0.4
0.2
435mW
MSOP-8 115°C/W
SOT23-6 230°C/W
0
0
25
50
75 85 100 125 150
Ambient Temperature (°C)
FIGURE 3. PACKAGE POWER DISSIPATION VS AMBIENT
TEMPERATURE
Package Mounted on a JEDEC JESD51-3 Low
Effective Thermal Conductivity Test Board
0.6
486mW
0.5
MAX TJ=125°C
0.4
0.3
0.2
391mWSOT23-M6S2O56P°-8C/2W06°C/W
0.1
0
0
25
50
75 85 100 125 150
Ambient Temperature (°C)
FIGURE 4. PACKAGE POWER DISSIPATION VS AMBIENT
TEMPERATURE
10
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