Micropower Single-Supply
Rail-to-Rail Input/Output Op Amps
OP191/OP291/OP491
FEATURES
NC
OUTA 1
8
+V
7
+V
–INA 2
7
OUTB
6
OUTA
+INA 3
6
–INB
5
NC
5
+INB
NC = NO CONNECT
–V 4
Figure 1. 8-Lead Narrow-Body SOIC
OUTA 1
14
13
Figure 2. 8-Lead Narrow-Body SOIC
OUTD
–INA 2
–IND
+INA 3
12
11
OUTA 1
–INA 2
+IND
+V 4
–V
10
9
–INC
OUTB 7
8
OUTC
–INB 6
Figure 3. 14-Lead Narrow-Body SOIC
+IND
–V
+INC
9
–INC
8
OUTB 7
–IND
10
+INB 5
OUTD
11
-
OP491
+V 4
+INC
–INB 6
+
13
12
+
+INA 3
00294-003
+INB 5
14
-
OUTC
Figure 4. 14-Lead PDIP
OUTA
1
14
OUTD
–INA
2
13
–IND
+INA
3
12
+IND
+V
4
11
–V
+INB
5
10
+INC
–INB
6
9
–INC
OUTB
7
8
OUTC
OP491
00294-005
OP491
OP291
00294-004
–V 4
00294-001
OP191
-
+INA 3
00294-002
8
+
Industrial process control
Battery-powered instrumentation
Power supply control and protection
Telecommunications
Remote sensors
Low voltage strain gage amplifiers
DAC output amplifiers
NC 1
–INA 2
+
APPLICATIONS
PIN CONFIGURATIONS
-
Single-supply operation: 2.7 V to 12 V
Wide input voltage range
Rail-to-rail output swing
Low supply current: 300 μA/amp
Wide bandwidth: 3 MHz
Slew rate: 0.5 V/μs
Low offset voltage: 700 μV
No phase reversal
Figure 5. 14-Lead TSSOP
GENERAL DESCRIPTION
The OP191, OP291, and OP491 are single, dual, and quad
micropower, single-supply, 3 MHz bandwidth amplifiers
featuring rail-to-rail inputs and outputs. All are guaranteed to
operate from a +3 V single supply as well as ±5 V dual supplies.
Fabricated on Analog Devices CBCMOS process, the OPx91
family has a unique input stage that allows the input voltage to
safely extend 10 V beyond either supply without any phase
inversion or latch-up. The output voltage swings to within
millivolts of the supplies and continues to sink or source
current all the way to the supplies.
The ability to swing rail-to-rail at both the input and output
enables designers to build multistage filters in single-supply
systems and to maintain high signal-to-noise ratios.
The OP191/OP291/OP491 are specified over the extended
industrial –40°C to +125°C temperature range. The OP191
single and OP291 dual amplifiers are available in 8-lead plastic
SOIC surface-mount packages. The OP491 quad is available in a
14-lead PDIP, a narrow 14-lead SOIC package, and a 14-lead
TSSOP.
Applications for these amplifiers include portable telecommunications equipment, power supply control and
protection, and interface for transducers with wide output
ranges. Sensors requiring a rail-to-rail input amplifier include
Hall effect, piezo electric, and resistive transducers.
Rev. E
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