EL2250, EL2450

FN7061 Rev 3.00

Page 12 of 15

May 19, 2006

Short Circuit Current Limit

The EL2250/EL2450 have internal short circuit protection

circuitry that protect it in the event of its output being shorted

to either supply rail. This limit is set to around 100mA

nominally and reduces with increasing junction temperature.

It is intended to handle temporary shorts. If an output is

shorted indefinitely, the power dissipation could easily

increase such that the part will be destroyed. Maximum

reliability is maintained if the output current never exceeds

±90mA. A heat sink may be required to keep the junction

temperature below absolute maximum when an output is

shorted indefinitely.

Power Dissipation

With the high output drive capability of the EL2250/EL2450,

it is possible to exceed the 150°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 power-supply

voltages, load conditions, or package type need to be

modified for the EL2250/EL2450 to remain in the safe

operating area.

The maximum power dissipation allowed in a package is

determined according to [1]:

where:

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 load, or

[2]:

where:

N = Number of amplifiers

various loads and output voltages according to [3]:

Figures 3 through 6 below show total single supply voltage

SO packages. The curves assume WORST CASE

FIGURE 2.

–



JA

---------------------------------------------

=

–



----------------



+











=

–





N



JA



---------------------------------------------------------------



+



 V

OUT

+

-------------------------------------------------------------------------------------------

=