ISL28268 Intersil Corporation, ISL28268 Datasheet - Page 13

• Manufacturer Part Number: ISL28268
• Description: (ISL28168 / ISL28268) Micro-power Single and Dual Rail-to-Rail Input-Output (RRIO) Low Input Bias Current Op Amps
• Manufacturer: Intersil Corporation

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same voltage as the high impedance input to eliminate
surface leakage. The guard ring does not need to be a
specific width, but it should form a continuous loop around
both inputs. For further reduction of leakage currents,
components can be mounted to the PC board using Teflon
standoff insulators.
Current Limiting
These devices 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.
FIGURE 43. GUARD RING EXAMPLE FOR UNITY GAIN
HIGH IMPEDANCE INPUT
IN
AMPLIFIER
13
V+
ISL28168, ISL28268
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 as follows:
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
DMAXTOTAL
MAX
S
OUTMAX
L
MAX
MAX
= Load resistance
= Supply voltage (Magnitude of V
= Thermal resistance of the package
=
= Maximum supply current of 1 amplifier
=
= Maximum ambient temperature
T
for each amplifier can be calculated as follows:
= 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
S
- V
OUTMAX
JMAX
)
+
) for all applications
and V
)
×
V
--------------------------- -
OUTMAX
September 13, 2007
-
)
R
L
MAX
(EQ. 2)
(EQ. 1)
FN6378.2
)