ISL28286_07 Datasheet, PDF (12/14 Pages) Intersil Corporation – Dual and Quad Micropower Single Supply Dual and Quad Micropower Single Supply Precision Op Amp

ISL28286, ISL28486
HIGH IMPEDANCE INPUT
V+
IN
FIGURE 38. GUARD RING EXAMPLE FOR UNITY GAIN
AMPLIFIER
Current Limiting
The ISL28286 and ISL28486 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.
Power Dissipation
It is possible to exceed the +150°C maximum junction
temperatures under certain load and power-supply
conditions. It is therefore important to calculate the
maximum junction temperature (T_JMAX) for all applications
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:
T_JMAX = T_MAX + (θ_JAxPD_MAXTOTAL)
(EQ. 1)
where:
• P_DMAXTOTAL is the sum of the maximum power
dissipation of each amplifier in the package (PD_MAX)
• PD_MAX for each amplifier can be calculated as follows:
PD_MAX
=
2*V_S × I_SMAX + (V_S
-
V_O
U
T
MA
X
)
×
V_{-----O----U----T----M-----A----X--}
R_{L (EQ.}
2)
where:
• T_MAX = Maximum ambient temperature
• θ_JA = Thermal resistance of the package
• PD_MAX = Maximum power dissipation of 1 amplifier
• V_S = Supply voltage (Magnitude of V₊ and V_-)
• I_MAX = Maximum supply current of 1 amplifier
• V_OUTMAX = Maximum output voltage swing of the
application
• R_L = Load resistance
12
FN6312.1
June 28, 2007