EL2250C Elantec Semiconductor, EL2250C Datasheet - Page 12

• Manufacturer Part Number: EL2250C
• Description: 125MHz Single Supply Dual/Quad Op Amps
• Manufacturer: Elantec Semiconductor

EL2250C, EL2450C
125MHz Single Supply Dual/Quad Op Amps
Short Circuit Current Limit
The EL2250C/EL2450C have internal short circuit pro-
tection 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 dis-
sipation could easily increase such that the part will be
destroyed. Maximum reliability is maintained if the out-
put current never exceeds ±90mA. A heat sink may be
required to keep the junction temperature below abso-
lute maximum when an output is shorted indefinitely.
Power Dissipation
W i t h t h e h i g h o u t p u t d r i v e c a p a b i l i t y o f t h e
EL2250C/EL2450C, it is possible to exceed the 150°C
Absolute Maximum junction temperature under certain
load current conditions. Therefore, it is important to cal-
culate the maximum junction temperature for the
application to determine if power-supply voltages, load
Figure 1.
Figure 2.
12
conditions, or package type need to be modified for the
EL2250C/EL2450C 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:
If we set the two PD
each other, and solve for V
curves for various loads and output voltages according
to [3]:
T
T
PD
N = Number of amplifiers
V
I
V
R
SMAX
JA
JMAX
AMAX
L
S
OUT
PD
= Total Supply Voltage
MAX
= Load Resistance tied to Ground
= Thermal Resistance of the Package
MAX
= Maximum Output Voltage of the Application
= Maximum Supply Current per amplifier
= Maximum Junction Temperature
= Maximum Ambient Temperature
= Maximum Power Dissipation in the Package.
=
V
N
S
=
PD
R
--------------------------------------------------------------- -
------------------------------------------------------------------------------------------ -
V
MAX
L
s
MAX
I
SMAX
T
=
JMAX
N
IS
T
-------------------------------------------- -
equations, [1] & [2], equal to
JMAX
+
JA
–
R
S
V
, we can get a family of
T
L
S
AMAX
–
J A
+
–
T
V
V
AMAX
OUT
OUT
+
V
O U T
V
---------------
R
OUT
L