FEATURES

LOW OFFSET VOLTAGE: 5

V (max)

ZERO DRIFT: 0.05

C max

QUIESCENT CURRENT: 750

A (max)

SINGLE-SUPPLY OPERATION

LOW BIAS CURRENT: 200pA (max)

SHUTDOWN

MicroSIZE PACKAGES

WIDE SUPPLY RANGE: 2.7V to 12V

APPLICATIONS

TRANSDUCER APPLICATIONS

TEMPERATURE MEASUREMENTS

ELECTRONIC SCALES

MEDICAL INSTRUMENTATION

BATTERY-POWERED INSTRUMENTS

HANDHELD TEST EQUIPMENT

DESCRIPTION

The OPA734 and OPA735 series of CMOS operational
amplifiers use auto-zeroing techniques to simultaneously
provide low offset voltage (5

V max) and near-zero drift

over time and temperature. These miniature, high-preci-
sion, low quiescent current amplifiers offer high input
impedance and rail-to-rail output swing within 50mV of the
rails. Either single or bipolar supplies can be used in the
range of +2.7V to +12V (

1.35V to

6V). They are

optimized for low-voltage, single-supply operation.

The OPA734 family includes a shutdown mode. Under
logic control, the amplifiers can be switched from normal
operation to a standby current that is 9

A (max) and the

output placed in a high-impedance state.

The single version is available in the MicroSIZE SOT23-5
(SOT23-6 for shutdown version) and the SO-8 packages.
The dual version is available in the MSOP-8 and SO-8
packages (MSOP-10 only for the shutdown version). All
versions are specified for operation from -40

C to +85

1/2

OP A 2735

10k

1/2

OP A 2735

1nF

10V

1nF

10nF

1nF

REF

= 15V

REF102

G = 1 + 2

OPA734, OPA2734
OPA735, OPA2735

SBOS282A - DECEMBER 2003 - REVISED FEBRUARY 2004

0.05

C max, SINGLE-SUPPLY CMOS

OPERATIONAL AMPLIFIERS

Zer

-Drift Series

PRODUCTION DATA information is current as of publication date. Products

conform to specifications per the terms of Texas Instruments standard warranty.

Production processing does not necessarily include testing of all parameters.

www.ti.com

2003-2004, Texas Instruments Incorporated

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.

All trademarks are the property of their respective owners.

OPA734, OPA2734

OPA735, OPA2735

SBOS282A - DECEMBER 2003 - REVISED FEBRUARY 2004

www.ti.com

ABSOLUTE MAXIMUM RATINGS

(1)

Supply Voltage

+13.2V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Signal Input Terminals, Voltage(2)

(V-) - 0.5V to (V+) + 0.5V

. . . . . . . . . . .

Current(2)

10mA

. . . . . . . . . . . . . . . . . . . . . . . . . . .

Output Short Circuit(3) Continuous

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operating Temperature

-40

C to +150

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Storage Temperature

-65

C to +150

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Junction Temperature

+150

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lead Temperature (soldering, 10s)

+300

. . . . . . . . . . . . . . . . . . . . . . . . . . .

ESD Rating (Human Body Model), OPA734

1000V

. . . . . . . . . . . . . . . . . . . .

ESD Rating (Human Body Model), OPA735, OPA2734, OPA2735

2000V

. . . .

(1) Stresses above these ratings may cause permanent damage. Exposure

to absolute maximum conditions for extended periods may degrade
device reliability. These are stress ratings only, and functional operation of
the device at these or any other conditions beyond those specified is not
implied.

(2) Input terminals are diode-clamped to the power-supply rails. Input signals

that can swing more than 0.5V beyond the supply rails should be current
limited to 10mA or less.

(3) Short-circuit to ground, one amplifier per package.

This integrated circuit can be damaged by ESD. Texas
Instruments recommends that all integrated circuits be
handled with appropriate precautions. Failure to observe

proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to
complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could
cause the device not to meet its published specifications.

PACKAGE/ORDERING INFORMATION

PRODUCT

PACKAGE-LEAD

PACKAGE

DESIGNATOR(1)

SPECIFIED

TEMPERATURE

RANGE

PACKAGE

MARKING

ORDERING

NUMBER

TRANSPORT MEDIA,

QUANTITY

Shutdown Version

OPA734

SOT23-6

DBV

-40

C to +85

NSB

OPA734AIDBVT

Tape and Reel, 250

OPA734AIDBVR

Tape and Reel, 3000

OPA734

SO-8

-40

C to +85

OPA734A

OPA734AID

Rails, 100

OPA734AIDR

Tape and Reel, 2500

OPA2734

MSOP-10

DGS

-40

C to +85

BGO

OPA2734AIDGST

Tape and Reel, 250

OPA2734AIDGSR

Tape and Reel, 2500

Non-Shutdown Version

OPA735

SOT23-5

DBV

-40

C to +85

NSC

OPA735AIDBVT

Tape and Reel, 250

OPA735AIDBVR

Tape and Reel, 3000

OPA735

SO-8

-40

C to +85

OPA735A

OPA735AID

Rails, 100

OPA735AIDR

Tape and Reel, 2500

OPA2735

SO-8

-40

C to +85

OPA2735A

OPA2735AID

Rails, 100

OPA2735AIDR

Tape and Reel, 2500

OPA2735

MSOP-8

DGK

-40

C to +85

BGN

OPA2735AIDGKT

Tape and Reel, 250

OPA2735AIDGKR

Tape and Reel, 2500

(1) For the most current specification and package information, refer to our web site at www.ti.com.

OPA734, OPA2734

OPA735, OPA2735

SBOS282A - DECEMBER 2003 - REVISED FEBRUARY 2004

www.ti.com

ELECTRICAL CHARACTERISTICS: V

5V (V

= +10V)

Boldface limits apply over the specified temperature range, T

= -40

C to +85

At TA = +25

C, RL = 10k

connected to VS/2, and VOUT = VS/2, unless otherwise noted.

OPA734, OPA2734, OPA735, OPA2735

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNIT

OFFSET VOLTAGE
Input Offset Voltage

VOS

vs Temperature

dVOS/dT

0.01

0.05

vs Power Supply

PSRR

VS = 2.7V to 12V, VCM = 0V

0.2

1.8

V/V

Long-Term Stability

Note (1)

Channel Separation, dc

0.1

V/V

INPUT BIAS CURRENT
Input Bias Current

VCM = VS/2

100

200

over Temperature

See Typical Characteristics

Input Offset Current

IOS

VCM = VS/2

200

300

NOISE
Input Voltage Noise, f = 0.01Hz to 1Hz

VPP

Input Voltage Noise, f = 0.1Hz to 10Hz

VPP

Input Voltage Noise Density, f = 1kHz

150

nV/

Input Current Noise Density, f = 1kHz

fA/

INPUT VOLTAGE RANGE
Common-Mode Voltage Range

VCM

(V-) - 0.1

(V+) - 1.5

Common-Mode Rejection Ratio

CMRR

(V-) - 0.1V < VCM < (V+) - 1.5V

115

130

INPUT CAPACITANCE
Differential

Common-Mode

OPEN-LOOP GAIN
Open-Loop Voltage Gain

AOL

(V-) + 100mV < VO < (V+) - 100mV

115

130

FREQUENCY RESPONSE
Gain-Bandwidth Product

GBW

1.6

MHz

Slew Rate

G = +1

1.5

OUTPUT
Voltage Output Swing from Rail

RL = 10k

Short-Circuit Current

ISC

Open-Loop Output Impedance

f = 1MHz, IO = 0

125

Capacitive Load Drive

CLOAD

See Typical Characteristics

ENABLE/SHUTDOWN
tOFF

1.5

tON(2)

150

VL (amplifier is shutdown)

V-

(V-) + 0.8

VH (amplifier is active)

(V-) + 2

V+

IQSD (per amplifier)

Input Bias Current of Enable Pin

POWER SUPPLY

Operating Voltage Range

2.7 to 12

(

1.35 to

Quiescent Current (per amplifier)

IO = 0

0.6

0.75

TEMPERATURE RANGE
Specified Range

-40

+85

Operating Range

-40

+150

Storage Range

-65

+150

Thermal Resistance

C/W

SOT23-5, SOT23-6

200

C/W

MSOP-8, MSOP-10, SO-8

150

C/W

(1) 300-hour life test at 150

C demonstrated randomly distributed variation in the range of measurement limits--approximately 1

(2) Device requires one complete auto-zero cycle to return to VOS accuracy.

OPA734, OPA2734

OPA735, OPA2735

SBOS282A - DECEMBER 2003 - REVISED FEBRUARY 2004

www.ti.com

TYPICAL CHARACTERISTICS

At TA = +25

C, VS =

5V (same as +10V).

OUTPUT VOLTAGE PRODUCTION DISTRIBUTION

Offset Voltage (

l
a

t
i
on

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

OUTPUT VOLTAGE DRIFT PRODUCTION DISTRIBUTION

Offset Voltage Drift (

l
a

t
i
on

0.00

0.01

0.02

0.03

0.04

0.05

Absolute Value;

Centered Around Zero

OUTPUT VOLTAGE SWING TO RAIL

vs OUTPUT CURRENT

Output Current (mA)

l
t
a

i
n

(
V

)

+85

+25

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

INPUT BIAS CURRENT vs TEMPERATURE

Temperature (

I
n

i
as

r
r
en

(
p

)

100

125

= V

10 Representative Units

1000

800

600

400

200

400

600

800

1000

INPUT BIAS CURRENT vs TEMPERATURE

Temperature (

I
n

i
as

r
r
en

(
p

)

100

125

= V

10 Representative Units

800

600

400

200

SUPPLY CURRENT vs TEMPERATURE

Temperature (

l
y

r
e

(

100

125

1.35V

OPA734, OPA2734

OPA735, OPA2735

SBOS282A - DECEMBER 2003 - REVISED FEBRUARY 2004

www.ti.com

TYPICAL CHARACTERISTICS (continued)

At TA = +25

C, VS =

5V (same as +10V).

OPEN-LOOP GAIN AND PHASE MARGIN

vs FREQUENCY

)

r
gi

(

)

Frequency (Hz)

180

160

140

120

100

180

160

140

120

100

0.1

100

10k

100k

10M

LARGE-SIGNAL RESPONSE

Time (5

s/div)

tput

l
t
age

(
2

/
di

)

SMALL-SIGNAL RESPONSE

Time (250ns/div)

tput

l
t
age

(
1

/
d

i
v

)

POSITIVE OVERVOLTAGE RECOVERY

Time (2.5

s/div)

(
2

/
d

)

Input

Output

OPA735

+5V

10 k

1 0k

NEGATIVE OVERVOLTAGE RECOVERY

Time (2.5

s/div)

(
2

/
d

)

Input

Output

OPA 73 5

+5 V

1 0k

10k

COMMON-MODE REJECTION RATIO vs FREQUENCY

(
d

)

Frequency (Hz)

140

120

100

10k

100k

100

10M

OPA734, OPA2734

OPA735, OPA2735

SBOS282A - DECEMBER 2003 - REVISED FEBRUARY 2004

www.ti.com

APPLICATIONS INFORMATION

The OPA734 and OPA735 series of op amps are
unity-gain stable and free from unexpected output phase
reversal. They use auto-zeroing techniques to provide low
offset voltage and demonstrate very low drift over time and
temperature.

Good layout practice mandates the use of a 0.1

capacitor placed closely across the supply pins.

For lowest offset voltage and precision performance,
circuit layout and mechanical conditions should be
optimized. Avoid temperature gradients that create
thermoelectric (Seebeck) effects in thermocouple
junctions formed from connecting dissimilar conductors.
These thermally-generated potentials can be made to
cancel by assuring that they are equal on both input
terminals:

Use low thermoelectric-coefficient connections
(avoid dissimilar metals).

Thermally isolate components from power supplies
or other heat sources.

Shield op amp and input circuitry from air currents
such as cooling fans.

Following these guidelines will reduce the likelihood of
junctions being at different temperatures, which can cause
thermoelectric voltages of 0.1

C or higher, depending

on the materials used.

OPERATING VOLTAGE

The OPA734 and OPA735 op amp family operates with a
power-supply range of +2.7V to +12V (

1.35V to

6V).

Supply voltages higher than +13.2V (absolute maximum)
can permanently damage the amplifier. Parameters that
vary over supply voltage or temperature are shown in the
Typical Characteristics section of this data sheet.

OPA734 ENABLE FUNCTION

The enable/shutdown digital input is referenced to the V-
supply voltage of the op amp. A logic HIGH enables the op
amp. A valid logic HIGH is defined as > (V-) + 2V. The valid
logic HIGH signal can be up to the positive supply,
independent of the negative power supply voltage. A valid
logic LOW is defined as < 0.8V above the V- supply pin.
If dual or split power supplies are used, be sure that logic
input signals are properly referred to the negative supply
voltage. The Enable pin is connected to internal pull-up
circuitry and will enable the device if this pin is left open
circuit.

The logic input is a CMOS input. Separate logic inputs are
provided for each op amp on the dual version. For
battery-operated applications, this feature can be used to
greatly reduce the average current and extend battery life.

The enable time is 150

s, which includes one full

auto-zero cycle required by the amplifier to return to V

accuracy. Prior to returning to full accuracy, the amplifier
may function properly, but with unspecified offset voltage.

Disable time is 1.5

s. When disabled, the output assumes

a high-impedance state. The disable state allows the
OPA734 to be operated as a gated amplifier, or to have the
output multiplexed onto a common analog output bus.

INPUT VOLTAGE

The input common-mode range extends from (V-) - 0.1V
to (V+) - 1.5V. For normal operation, the inputs must be
limited to this range. The common-mode rejection ratio is
only valid within the specified input common-mode range.
A lower supply voltage results in lower input common-
mode range; therefore, attention to these values must be
given when selecting the input bias voltage. For example,
when operating on a single 3V power supply, common-
mode range is from 0.1V below ground to half the
power-supply voltage.

Normally, input bias current is approximately 100pA;
however, input voltages exceeding the power supplies can
cause excessive current to flow in or out of the input pins.
Momentary voltages greater than the power supply can be
tolerated if the input current is limited to 10mA. This is
easily accomplished with an input resistor, as shown in
Figure 1.

OPA735

+5V

OUT

10mA max

OVERLOAD

Current-limited resistor required
if input voltage exceeds supply
rails by

0.5V.

Figure 1. Input Current Protection

INTERNAL OFFSET CORRECTION

The OPA734 and OPA735 series of op amps use an
auto-zero topology with a time-continuous 1.6MHz op amp
in the signal path. This amplifier is zero-corrected every
100

s using a proprietary technique. Upon power-up, the

amplifier requires one full auto-zero cycle of approximately
100

s in addition to the start-up time for the bias circuitry

to achieve specified V

accuracy. Prior to this time, the

amplifier may function properly but with unspecified offset
voltage.

OPA734, OPA2734

OPA735, OPA2735

SBOS282A - DECEMBER 2003 - REVISED FEBRUARY 2004

www.ti.com

Low-gain (< 20) operation demands that the auto-zero
circuitry correct for common-mode rejection errors of the
main amplifier. Because these errors can be larger than
0.1% of a full-scale input step change, one calibration
cycle (100

s) can be required to achieve full accuracy.

The term clock feedthrough describes the presence of the
clock frequency in the output spectrum. In auto-zeroed op
amps, clock feedthrough may result from the settling of the
internal sampling capacitor, or from the small amount of
charge injection that occurs during the sample-and-hold of
the op amp offset voltage. Feedthrough can be minimized
by keeping the source impedance relatively low (< 1k

)

and matching the source impedance on both input
terminals. If the source resistance is high (> 1k

)

feedthrough can generally be reduced with a capacitor of
1nF or greater in parallel with the source or feedback
resistors. See the circuit application examples.

LAYOUT GUIDELINES

Attention to good layout practices is always recom-
mended. Keep traces short. When possible, use a PCB
ground plane with surface-mount components placed as
close to the device pins as possible. Place a 0.1

capacitor closely across the supply pins. These guidelines
should be applied throughout the analog circuit to improve
performance and provide benefits such as reducing the
electromagnetic-interference (EMI) susceptibility.

OUT

REF

OPA734

R R

+10V

1nF

Figure 2. Single Op Amp Bridge Amplifier Circuit

1 /2

OP A 2 7 35

10k

1 /2

OP A 2 7 35

1nF

10V

(1)

1nF

(1)

10nF

(1)

1nF

REF

= 15V

REF102

NOTE: (1) Place close to input pins.

R R

G = 1 + 2

Figure 3. Differential Output Bridge Amplifier

OPA734, OPA2734

OPA735, OPA2735

SBOS282A - DECEMBER 2003 - REVISED FEBRUARY 2004

www.ti.com

VIN

VREF

10V

42.2k

14.7k

20.8k

19.6k

0V to 10V

20.8k

5.11k

0V to 5V

10.5k

10k

Figure 4. Driving ADC

10k

6.8k

22k

TPS434 Thermopile

1.5M

+5V

10k

OPA735

100nF

10k

+5V

1/2

OPA2703

11k

+5V

1/2

OPA2703

REF1112

OUT

NOTE: The TPS434, by Perkin Elmer Optoelectronics is a thermopile detector
with integrated thermistor for cold-junction reference.

Figure 5. Thermopile Non-Contact Surface Temperature Measurement

ADS8342
ADS8325
ADS1100

REF

= 10k

10k

1nF

500pF

0.1V to 4.9V

300

= 1nF

Optional filter for use

with SAR-type

converters

operating at

sampling rates of

50kHz and below.

+5V

OPA735

OPA734, OPA2734

OPA735, OPA2735

SBOS282A - DECEMBER 2003 - REVISED FEBRUARY 2004

www.ti.com

536k

268k

OPA735

5nF

10nF

OUT

+5V

; where

R = R

= R

= 2R

C = C

= C

= 60Hz for values shown)

Figure 6. Twin-T Notch Filter

NOTE: FilterPro is a low-pass filter design program available for download at no cost from TI's web site (www.ti.com).
The program can be used to easily determine component values for other cutoff frequencies or filter types.

68.0nF

6.80nF

20.8k

2.64k

15.0nF

10.6k

1/2

OP A2 735

1/2

O PA 2735

OUT

Cutoff frequency = 2kHz for values shown.

Figure 7. High DC Accuracy, 3-Pole Low-Pass Filter

1/2

OP A 27 35

1/2

OP A 27 35

10 k

= 10 k

10 k

OUT

1nF

NOTE: Dynamic range of the circuit is not reduced by
the diode voltage drop since the diode is not in the signal path.
Application Bulletin Precision Absolute Value Circuits (SBOA068)
is available at www.ti.com and provides further information about rectifier circuits.

Figure 8. Precision Full-Wave Rectifier with Full Dynamic Range

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