ISL28191_08 Datasheet, PDF (11/16 Pages) Intersil Corporation – Single and Dual Single Supply Ultra-Low Noise, Low Distortion Rail-to-Rail Output, Op Amp

ISL28191, ISL28291
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 SOIC
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 the output short circuit current is specified
and tested with R_L = 10Ω.
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_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 in Equation 1:
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 in Equation 2:
PD_MAX
=
2*V_S × I_SMAX + (V_S
-
V_OUTMAX
)
×
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
• I_MAX = Maximum supply current of 1 amplifier
• V_OUTMAX = Maximum output voltage swing of the
application
• R_L = Load resistance
11
FN6156.5
February 20, 2008