Datasheet

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APPLICATIONS INFORMATION
OPERATING VOLTAGE
V =DGND
REF
Digital
Logic
Enable
OPA728
+12V
a)Single-SupplyConfiguration
b)Dual-SupplyConfiguration
V =D
REF
GND
REF
REF
Digital
Logic
Enable
OPA728
+5V
-5V
V
OUT
V
OUT
ENABLE/SHUTDOWN
INPUT OVER-VOLTAGE PROTECTION
COMMON-MODE VOLTAGE RANGE
R
OPA727
V+
V-
V
IN
V
OUT
10mAmax
I
OVERLOAD
OPA727 , , OPA2727
OPA4727 , OPA728
SBOS314H – SEPTEMBER 2004 – REVISED APRIL 2007
Common-mode rejection is excellent throughout the
The OPA727 and OPA728 family of op amps use
input voltage range from V– to (V+) – 3V. CMRR
e-trim, an adjustment to offset voltage and
decreases somewhat as the common-mode voltage
temperature drift made during the final steps of
extends to (V+) – 2.5V, but remains very good and is
manufacturing after the plastic molding is completed.
tested throughout this range. See the Electrical
This compensates for performance shifts that can
Characteristics table for details.
occur during the molding process. Through e-trim,
the OPA727 and OPA728 deliver excellent offset
voltage (150 µ V max) and extremely low offset
voltage drift (1.5 µ V/ ° C). Additionally, these 20MHz
CMOS op amps have a fast slew rate, low noise, and
excellent PSRR, CMRR, and A
OL
. They can operate
on typically 4.3mA quiescent current from a single (or
split) supply in the range of 4V to 12V ( ± 2V to ± 6V),
making them highly versatile and easy to use. They
are stable in a unity-gain configuration.
Power-supply pins should be bypassed with 1nF
ceramic capacitors in parallel with 1 µ F tantalum
capacitors.
OPA727 series op amps are specified from 4V to
12V supplies over a temperature range of –40 ° C to
+125 ° C. They will operate well in ± 5V or +5V to
+12V power-supply systems. Parameters that vary
significantly with operating voltage or temperature
are shown in the Typical Characteristics.
Figure 28. Enable Reference Pin Connection for
OPA727 series op amps require approximately
Single- and Dual-Supply Configurations
4.3mA quiescent current. The enable/shutdown
feature of the OPA728 allows the op amp to be shut
off to reduce this current to approximately 6 µ A.
The enable/shutdown input is referenced to the
Device inputs are protected by ESD diodes that will
Enable Reference Pin, REF (see Pin Configurations ).
conduct if the input voltages exceed the power
This pin can be connected to logic ground in
supplies by more than approximately 300mV.
dual-supply op amp configurations to avoid
Momentary voltages greater than 300mV beyond the
level-shifting the enable logic signal, as shown in
power supply can be tolerated if the current is limited
Figure 28 .
to 10mA. This is easily accomplished with an input
resistor in series with the op amp, as shown in
The Enable Reference Pin voltage, V
REF
, must not
Figure 29 . The OPA727 series features no phase
exceed (V+) – 2V. It may be set as low as V–. The
inversion when the inputs extend beyond supplies, if
amplifier is enabled when the Enable Pin voltage is
the input is current limited.
greater than V
REF
+ 2V. The amplifier is disabled
(shutdown) if the Enable Pin voltage is less than
V
REF
+ 0.8V. The Enable Pin is connected to internal
pull-up circuitry and will enable the device if left
unconnected.
The input common-mode voltage range of the
OPA727 and OPA728 series extends from V– to
(V+) – 2.5V.
Figure 29. Input Current Protection for Voltages
Exceeding the Supply Voltage
11
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