ISL28291 Intersil Corporation, ISL28291 Datasheet - Page 11

• Manufacturer Part Number: ISL28291
• Description: Single And Dual Ultra-low Noise, Rail-to-rail, Op Amp
• Manufacturer: Intersil Corporation

reduce the risk of oscillation. The combination of a 4.7µF
tantalum capacitor in parallel with a 0.01µF capacitor has
been shown to work well when placed at each supply pin.
For good AC performance, parasitic capacitance should be
kept to a minimum, especially at the inverting input. When
ground plane construction is used, it should be removed
from the area near the inverting input to minimize any stray
capacitance at that node. Carbon or Metal-Film resistors are
acceptable with the Metal-Film resistors giving slightly less
peaking and bandwidth because of additional series
inductance. Use of sockets, particularly for the SO package,
should be avoided if possible. Sockets add parasitic
inductance and capacitance which will result in additional
peaking and overshoot.
Current Limiting
The ISL28191 and ISL28291 have no internal current-
limiting circuitry. If the output is shorted, it is possible to
exceed the Absolute Maximum Rating for output current or
power dissipation, potentially resulting in the destruction of
the device. This is why output short circuit current is
specified and tested with R
Power Dissipation
It is possible to exceed the +125°C maximum junction
temperatures under certain load and power-supply
conditions. It is therefore important to calculate the
maximum junction temperature (T
to determine if power supply voltages, load conditions, or
package type need to be modified to remain in the safe
operating area. These parameters are related in Equation 1:
where:
• P
• PD
where:
• T
• θ
• PD
• V
• I
• V
• R
T
PD
JMAX
dissipation of each amplifier in the package (PD
application
MAX
MAX
JA
MAX
DMAXTOTAL
S
OUTMAX
L
MAX
MAX
= Load resistance
= Supply voltage
= Thermal resistance of the package
=
= Maximum supply current of 1 amplifier
=
= Maximum ambient temperature
T
for each amplifier can be calculated in Equation 2:
= Maximum power dissipation of 1 amplifier
2*V
MAX
= Maximum output voltage swing of the
S
+
×
is the sum of the maximum power
(
I
θ
SMAX
JA
xPD
+
MAXTOTAL
(
V
L
S
= 10Ω.
11
- V
OUTMAX
JMAX
)
) for all applications
)
×
V
--------------------------- -
OUTMAX
R
L
MAX
ISL28191, ISL28291
(EQ. 1)
(EQ. 2)
)
September 19, 2007
FN6156.4