ISL24020_14 Datasheet, PDF (8/10 Pages) Intersil Corporation – Low Cost, 60MHz Rail-to-Rail Input-Output Op-Amp

ISL24020
Applications Information
Product Description
The ISL24020 voltage feedback amplifier is fabricated using
a high voltage CMOS process. It exhibits rail-to-rail input and
output capability, is unity gain stable and has low power
consumption (2.5mA). These features make the ISL24020
ideal for a wide range of general-purpose applications.
Connected in voltage follower mode and driving a load of
1kΩ, the ISL24020 has a -3dB bandwidth of 60MHz while
maintaining a 75V/µs slew rate.
Operating Voltage, Input, and Output
The ISL24020 is specified with a single nominal supply
voltage from 5V to 15V or a split supply with its total range
from 5V to 15V. Correct operation is guaranteed for a supply
range of 4.5V to 16.5V. Most ISL24020 specifications are
stable over both the full supply range and operating
temperatures of -40°C to +85°C. Parameter variations with
operating voltage and/or temperature are shown in the
“Typical Performance Curves” on page 3.
The input common-mode voltage range of the ISL24020
extends 500mV beyond the supply rails. The output swings
of the ISL24020 typically extend to within 100mV of positive
and negative supply rails with load currents of 5mA.
Decreasing load currents will extend the output voltage
range even closer to the supply rails. Figure 26 shows the
input and output waveforms for the device in the unity-gain
configuration. Operation is from ±5V supply with a 1kΩ load
connected to GND. The input is a 10V_P-P sinusoid. The
output voltage is approximately 9.8V_P-P.
V_S = ±5V, T_A = +25°C, A_V = 1, V_IN = 10V_P-P
5V
10µs
5V
FIGURE 26. OPERATION WITH RAIL-TO-RAIL INPUT AND
OUTPUT
Short Circuit Current Limit
The ISL24020 will limit the short circuit current to ±180mA if
the output is directly shorted to the positive or the negative
supply. If an output is shorted indefinitely, the power
dissipation could easily increase such that the device may
be damaged. Maximum reliability is maintained if the output
continuous current never exceeds ±65mA. This limit is set by
the design of the internal metal interconnects.
Output Phase Reversal
The ISL24020 is immune to phase reversal as long as the
input voltage is limited from V_S- -0.5V to V_S+ +0.5V.
Figure 27 shows a photo of the output of the device with the
input voltage driven beyond the supply rails. Although the
device's output will not change phase, the input's
overvoltage should be avoided. If an input voltage exceeds
supply voltage by more than 0.6V, electrostatic protection
diodes placed in the input stage of the device begin to
conduct and overvoltage damage could occur.
V_S = ±2.5V, T_A = +25°C, A_V = 1, V_IN = 6V_P-P
1V
10µs
1V
FIGURE 27. OPERATION WITH BEYOND-THE-RAILS INPUT
Power Dissipation
With the high-output drive capability of the ISL24020
amplifier, it is possible to exceed the +125°C
'absolute-maximum junction temperature' under certain load
current conditions. Therefore, it is important to calculate the
maximum junction temperature for the application to
determine if load conditions need to be modified for the
amplifier to remain in the safe operating area.
The maximum power dissipation allowed in a package is
determined according to:
P_DMAX
=
T_{----J---M-----A----X-----–-----}T_{----A---M-----A----X--}
θ_JA
(EQ. 1)
where:
• T_JMAX = Maximum junction temperature
• T_AMAX = Maximum ambient temperature
• Θ_JA = Thermal resistance of the package
• P_DMAX = Maximum power dissipation in the package
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 loads, or:
P_DMAX = Σi[V_S × I_SMAX + (V_S+ – V_OUTi ) × I_LOADi ]
(EQ. 2)
when sourcing, and:
P_DMAX = Σi[V_S × I_SMAX + (V_OUTi – V_S- ) × I_LOADi ]
(EQ. 3)
when sinking.
8
FN6735.0
October 2, 2008