EL2257C Elantec Semiconductor, EL2257C Datasheet - Page 18

• Manufacturer Part Number: EL2257C
• Description: 125 MHz Single Supply/ Clamping Op Amps
• Manufacturer: Elantec Semiconductor

EL2257C/EL2357C
125 MHz Single Supply, Clamping Op Amps
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
EL2257C/EL2357C, 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
conditions, or package type need to be modified for the
EL2257C/EL2357C to remain in the safe operating area.
The maximum power dissipation allowed in a package is
determined by:
where:
• T
• T
•
• PD
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:
where:
• N = Number of amplifiers
• V
• I
• V
• R
If we set the two PD
each other, and solve for V
Package.
PD
SMAX
JA
AMAX
JMAX
OUT
L
S
MAX
MAX
= Total Supply Voltage
= Load Resistance tied to Ground
= Thermal Resistance of the Package
= Maximum Output Voltage of the Application
= Maximum Supply Current per amplifier
= Maximum Junction Temperature
= Maximum Ambient Temperature
= Maximum Power Dissipation in the
=
PD
N
MAX
V
S
MAX
=
I
SMAX
T
--------------------------------------------- -
equations, [1] and [2], equal to
JMAX
S
+
, we can get a family of
–
JA
V
T
S
AMAX
–
V
OUT
V
--------------- -
OUT
R
L
18
curves for various loads and output voltages according
to:
Figures 11 and 12 below show total single supply volt-
age V
PDIP and SOIC packages. The curves assume WORST
CASE conditions of T
amplifier.
S
V
vs. R
S
=
L
R
---------------------------------------------------------------- -
---------------------------------------------------------------------------------------------- -
for various output voltage swings for the
L
EL2257 Single Supply Voltage
vs. R
V
EL2357 Single Supply Voltage
vs. R
V
OUT
OUT
T
Load
Load
JMAX
and Packages
and Packages
N
Figure 12.
Figure 11.
A
I
for Various
for Various
S
= +85°C and I
JA
–
R
T
L
AMAX
+
V
OUT
+
S
V
= 6.5 mA per
OUT
2