Low Cost, Low Power, Rail-to-Rail

OPERATIONAL AMPLIFIERS

Micro

Amplifier

Series

PDS-1485B

Printed in U.S.A. June, 2000

FEATURES

LOW QUIESCENT CURRENT: 150

A typ

RAIL-TO-RAIL INPUT

RAIL-TO-RAIL OUTPUT (within 1mV)

SINGLE SUPPLY CAPABILITY

LOW COST

Micro

SIZE PACKAGE OPTIONS:

SOT23-5
MSOP-8
TSSOP-14

BANDWIDTH: 1MHz

SLEW RATE: 1V/

THD + NOISE: 0.006%

APPLICATIONS

COMMUNICATIONS

PCMCIA CARDS

DATA ACQUISITION

PROCESS CONTROL

AUDIO PROCESSING

ACTIVE FILTERS

TEST EQUIPMENT

CONSUMER ELECTRONICS

DESCRIPTION

The OPA342 series rail-to-rail CMOS operational
amplifiers are designed for low cost, low power,
miniature applications. They are optimized to operate
on a single supply as low as 2.5V with an input
common-mode voltage range that extends 300mV
beyond the supplies.

Rail-to-rail input/output and high-speed operation make
them ideal for driving sampling Analog-to-Digital Con-
verters (ADC). They are also well suited for general
purpose and audio applicaitons and providing I/V con-
version at the output of Digital-to-Analog Converters
(DAC). Single, dual and quad versions have identical
specs for design flexibility.

The OPA342 series offers excellent dynamic response
with a quiescent current of only 250

A max. Dual and

quad designs feature completely independent circuitry
for lowest crosstalk and freedom from interaction.

OPA342

OPA2342
OPA4342

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Twx: 910-952-1111 · Internet: http://www.burr-brown.com/ · Cable: BBRCORP · Telex: 066-6491 · FAX: (520) 889-1510 · Immediate Product Info: (800) 548-6132

For most current data sheet and other product

information, visit www.burr-brown.com

OPA342

OPA2342

OPA4342

SINGLE

DUAL

QUAD

PACKAGE

OPA342

OPA2342

OPA4342

SOT23-5

MSOP-8

SO-8

TSSOP-14

SO-14

DIP-14

SPICE MODEL available at www.burr-brown.com.

OPA342, 2342, 4342

SPECIFICATIONS: V

= 2.7V to 5.5V

At T

= +25

C, R

= 10k

connected to V

/ 2 and V

OUT

= V

/ 2, unless otherwise noted.

Boldface limits apply over the temperature range, T

= 40

C to +85

OPA342NA, UA

OPA2342EA, UA

OPA4342EA, UA, PA

PARAMETER

CONDITION

MIN

TYP

MAX

UNITS

OFFSET VOLTAGE
Input Offset Voltage

= V

/ 2

= 40

C to +85

vs Temperature

/dT

vs Power Supply

PSRR

= 2.7V to 5.5V, V

< (V+) -1.8V

200

V/V

= 40

C to +85

= 2.7V to 5.5V, V

< (V+) -1.8V

250

V/V

Channel Separation, dc

0.2

V/V

f = 1kHz

132

INPUT BIAS CURRENT
Input Bias Current

0.2

= 40

C to +85

See Typical Curve

Input Offset Current

0.2

NOISE
Input Voltage Noise, f = 0.1Hz to 50kHz

Vrms

Input Voltage Noise Density, f = 1kHz

nV/

Current Noise Density, f = 1kHz

0.5

fA/

INPUT VOLTAGE RANGE
Common-Mode Voltage Range

0.3

(V+) + 0.3

Common-Mode Rejection Ratio

CMRR

= +5.5V, 0.3V

< V

< (V+) - 1.8

= 40

C to +85

= +5.5V, 0.3V

< V

< (V+) - 1.8

Common-Mode Rejection Ratio

CMRR

= +5.5V, 0.3V

< V

< 5.8V

= 40

C to +85

= +5.5V, 0.3V

< V

< 5.8V

Common-Mode Rejection Ratio

CMRR

= +2.7V, 0.3V

< V

< 3V

= 40

C to +85

= +2.7V, 0.3V

< V

< 3V

INPUT IMPEDANCE
Differential

|| 3

|| pF

Common-Mode

|| 6

|| pF

OPEN-LOOP GAIN
Open-Loop Voltage Gain

= 100k

, 10mV < V

< (V+) 10mV

104

124

= 40

C to +85

= 100k

, 10mV < V

< (V+) 10mV

100

= 5k

, 400mV < V

< (V+) 400mV

114

= 40

C to +85

= 5k

, 400mV < V

< (V+) 400mV

FREQUENCY RESPONSE

= 100pF

Gain-Bandwidth Product

GBW

G = 1

MHz

Slew Rate

Settling Time, 0.1%

= 5.5V, 2V Step

0.01%

= 5.5V, 2V Step

Overload Recovery Time

· G = V

2.5

Total Harmonic Distortion + Noise, f = 1kHz THD+N

= 5.5V, V

= 3Vp-p

(1)

, G = 1

0.006

OUTPUT
Voltage Output Swing from Rail

(2)

= 100k

, A

96dB

= 100k

104dB

= 40

C to +85

= 100k

100dB

= 5k

, A

96dB

400

= 40

C to +85

= 5k

90dB

400

Short-Circuit Current

Per Channel

Capacitive Load Drive

LOAD

See Typical Curve

POWER SUPPLY
Specified Voltage Range

2.7

5.5

Operating Voltage Range

2.5 to 5.5

Quiescent Current (per amplifier)

= 0A

150

250

= 40

C to +85

300

TEMPERATURE RANGE
Specified Range

+85

Operating Range

+125

Storage Range

+150

Thermal Resistance

SOT23-5 Surface Mount

200

C/W

MSOP-8 Surface Mount

150

C/W

SO-8 Surface Mount

150

C/W

TSSOP-14 Surface Mount

100

C/W

SO-14 Surface Mount

100

C/W

DIP-14

100

C/W

NOTE: (1) V

OUT

= 0.25V to 3.25V. (2) Output voltage swings are measured between the output and power-supply rails.

OPA342, 2342, 4342

PACKAGE

SPECIFIED

DRAWING

TEMPERATURE

PACKAGE

ORDERING

TRANSPORT

PRODUCT

PACKAGE

NUMBER

RANGE

MARKING

NUMBER

(1)

MEDIA

OPA342NA

SOT23-5

331

C to +85

B42

OPA342NA /250

Tape and Reel

OPA342NA /3K

Tape and Reel

OPA342UA

SO-8

182

C to +85

OPA342UA

Rails

OPA342UA /2K5

Tape and Reel

OPA2342EA

MSOP-8

337

C to +85

C42

OPA2342EA /250

Tape and Reel

OPA2342EA /2K5

Tape and Reel

OPA2342UA

SO-8

182

C to +85

OPA2342UA

Rails

OPA2342UA /2K5

Tape and Reel

OPA4342EA

TSSOP-14

357

C to +85

OPA4342EA

OPA4342EA /250

Tape and Reel

OPA4342EA /2K5

Tape and Reel

OPA4342UA

SO-14

235

C to +85

OPA4342UA

Rails

OPA4342UA /2K5

Tape and Reel

OPA4342PA

DIP-14

010

C to +85

OPA4342PA

Rails

NOTE: (1) Models with a slash (/) are available only in Tape and Reel in the quantities indicated (e.g., /3K indicates 3000 devices per reel). Ordering 3000 pieces
of "OPA342NA/3K" will get a single 3000-piece Tape and Reel.

PACKAGE/ORDERING INFORMATION

Supply Voltage, V+ to V- ................................................................... 7.5V
Signal Input Terminals, Voltage

(2)

..................... (V) 0.5V to (V+) +0.5V

Current

(2)

.................................................... 10mA

Output Short-Circuit

(3)

.............................................................. Continuous

Operating Temperature .................................................. 55

C to +125

Storage Temperature ..................................................... 65

C to +150

Junction Temperature ...................................................................... 150

Lead Temperature (soldering, 10s) ................................................. 300

ESD Tolerance (Human Body Model) ............................................ 4000V

NOTES: (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. Functional opera-
tion of the device at these conditions, or beyond the specified operating
conditions, 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.

ABSOLUTE MAXIMUM RATINGS

(1)

ELECTROSTATIC
DISCHARGE SENSITIVITY

This integrated circuit can be damaged by ESD. Burr-Brown
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 degrada-
tion 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.

OPA342, 2342, 4342

TYPICAL PERFORMANCE CURVES

At T

= +25

C, V

= +5V, and R

= 10k

connected to V

/2, unless otherwise noted.

POWER SUPPLY AND COMMON-MODE

REJECTION RATIO vs FREQUENCY

Rejection Ratio (dB)

Frequency (Hz)

100

10k

100k

100

+PSRR

CMRR

PSRR

CHANNEL SEPARATION vs FREQUENCY

100

Channel Separation (dB)

Frequency (Hz)

10k

100k

140

120

100

Dual and quad devices.
G = 1, all channels.
Quad measured channel
A to D or B to C--other
combinations yield improved
rejection.

VOLTAGE AND CURRENT NOISE

SPECTRAL DENSITY vs FREQUENCY

Voltage Noise (nV/

Hz)

Frequency (Hz)

100

10k

100k

10M

10000

1000

100

Current Noise (fA/

Hz)

100

0.1

TOTAL HARMONIC DISTORTION + NOISE

vs FREQUENCY

THD+N (%)

Frequency (Hz)

100

10k

20k

0.1

0.010

0.001

OPEN-LOOP GAIN/PHASE vs FREQUENCY

0.1

Gain (dB)

120

150

180

Phase (

)

Frequency (Hz)

100

10k

100k

10M

120

100

Gain

Phase

MAXIMUM OUTPUT VOLTAGE vs FREQUENCY

10k

Maximum Output Voltage (Vp-p)

Frequency (Hz)

100k

= +2.7V

= +5.5V

= +5V

OPA342, 2342, 4342

TYPICAL PERFORMANCE CURVES

(Cont.)

At T

= +25

C, V

= +5V, and R

= 10k

connected to V

/2, unless otherwise noted.

OPEN-LOOP GAIN, COMMON-MODE REJECTION RATIO,

AND POWER SUPPLY REJECTION vs TEMPERATURE

, CMRR, PSRR (dB)

Temperature (

125

100

150

140

120

100

CMRR

PSRR

INPUT BIAS CURRENT vs TEMPERATURE

Input Bias Current (pA)

Temperature (

100

125

10000

1000

100

0.1

QUIESCENT CURRENT AND

SHORT-CIRCUIT CURRENT vs TEMPERATURE

Quiescent Current (

Temperature (

100

125

200

175

150

135

100

Short-Circuit Current (mA)

SLEW RATE vs TEMPERATURE

Slew Rate (V/

Temperature (

+SR

100

125

1.2

0.8

0.6

0.4

0.2

INPUT BIAS CURRENT

vs COMMON-MODE VOLTAGE

Input Bias Current (pA)

Common-Mode Voltage (V)

V+

Supply

Input voltage

0.3V

can cause op amp output
to lock up. See text.

QUIESCENT CURRENT AND

SHORT-CIRCUIT CURRENT vs SUPPLY VOLTAGE

Quiescent Current (

Supply Voltage (V)

160

155

150

145

140

Short-Circuit Current (mA)

OPA342, 2342, 4342

TYPICAL PERFORMANCE CURVES

(Cont.)

At T

= +25

C, V

= +5V, and R

= 10k

connected to V

/2, unless otherwise noted.

OUTPUT VOLTAGE SWING vs OUTPUT CURRENT

Output Voltage (V)

Output Current (mA)

V+

(V+) 1

(V+) 2

OPEN-LOOP GAIN vs OUTPUT VOLTAGE SWING

120

110

100

Open-Loop Gain (dB)

Output Voltage Swing from Rail (mV)

120

100

= 5k

= 100k

OFFSET VOLTAGE

PRODUCTION DISTRIBUTION

Percent of Amplifiers (%)

Offset Voltage (mV)

5.4

4.8

4.2

3.6

2.4

1.8

1.2

0.6

1.2

1.8

2.4

3.6

4.2

4.8

5.4

Typical production
distribution of
packaged units.

OFFSET VOLTAGE DRIFT

PRODUCTION DISTRIBUTION

Percent of Amplifiers (%)

Offset Voltage Drift (

Typical production
distribution of
packaged units.

Quiescent Current (

QUIESCENT CURRENT

PRODUCTION DISTRIBUTION

Percent of Amplifiers (%)

<25

<50

<75

<100

<125

<150

<175

<200

<225

<250

SETTLING TIME vs CLOSED-LOOP GAIN

Settling Time (

Closed-Loop Gain (V/V)

100

0.01%

0.1%

1000

400

350

300

250

200

150

100

OPA342, 2342, 4342

APPLICATIONS INFORMATION

OPA342 series op amps are unity gain stable and can operate
on a single supply, making them highly versatile and easy to
use.

Rail-to-rail input and output swing significantly increases
dynamic range, especially in low supply applications. Figure
1 shows the input and output waveforms for the OPA342 in
unity-gain configuration. Operation is from V

= +5V with

a 10k

load connected to V

/2. The input is a 5Vp-p

sinusoid. Output voltage is approximately 4.997Vp-p.

Power supply pins should be by passed with 0.01pF ceramic
capacitors.

OPERATING VOLTAGE

OPA342 series op amps are fully specified and guaranteed
from +2.7V to +5.5V. In addition, many specifications apply
from 40ºC to +85ºC. Parameters that vary significantly
with operating voltages or temperature are shown in the
Typical Performance Curves.

RAIL-TO-RAIL INPUT

The input common-mode voltage range of the OPA342
series extends 300mV beyond the supply rails. This is
achieved with a complementary input stage--an N-channel
input differential pair in parallel with a P-channel differen-
tial pair (see Figure 2). The N-channel pair is active for input
voltages close to the positive rail, typically (V+) 1.3V to
300mV above the positive supply, while the P-channel pair
is on for inputs from 300mV below the negative supply to
approximately (V+) 1.3V. There is a small transition re-
gion, typically (V+) 1.5V to (V+) 1.1V, in which both
pairs are on. This 400mV transition region can vary 300mV
with process variation. Thus, the transition region (both
stages on) can range from (V+) 1.8V to (V+) 1.4V on the
low end, up to (V+) 1.2V to (V+) 0.8V on the high end.
Within the 400mV transition region PSRR, CMRR, offset
voltage, offset drift, and THD may be degraded compared to
operation outside this region. For more information on
designing with rail-to-rail input op amps, see Figure 3
"Design Optimization with Rail-to-Rail Input Op Amps."

FIGURE 2. Simplified Schematic.

BIAS1

BIAS2

Class AB

Control

Circuitry

(Ground)

V+

Reference

Current

FIGURE 1. Rail-to-Rail Input and Output.

s/div

1V/div

Output (inverted on scope)

Input

G = +1, V

= +5V

OPA342, 2342, 4342

COMMON-MODE REJECTION

The CMRR for the OPA342 is specified in several ways so
the best match for a given application may be used. First, the
CMRR of the device in the common-mode range below the
transition region (V

< (V+) 1.8V) is given. This speci-

fication is the best indicator of the capability of the device
when the application requires use of one of the differential
input pairs. Second, the CMRR at V

= 5.5V over the entire

common-mode range is specified. Third, the CMRR at V

2.7V over the entire common-mode range is provided. These
last two values include the variations seen through the
transition region.

INPUT VOLTAGE BEYOND THE RAILS

If the input voltage can go more than 0.3V below the
negative power supply rail (single-supply ground), special
precautions are required. If the input voltage goes suffi-
ciently negative, the op amp output may lock up in an
inoperative state. A Schottky diode clamp circuit will pre-
vent this--see Figure 4. The series resistor prevents exces-
sive current (greater than 10mA) in the Schottky diode and
in the internal ESD protection diode, if the input voltage can
exceed the positive supply voltage. If the signal source is
limited to less than 10mA, the input resistor is not required.

RAIL-TO-RAIL OUTPUT

A class AB output stage with common-source transistors is
used to achieve rail-to-rail output. This output stage is
capable of driving 600

loads connected to any potential

between V+ and ground. For light resistive loads (> 50k

the output voltage can typically swing to within 1mV from
supply rail. With moderate resistive loads (2k

to 50k

the output can swing to within a few tens of milli-volts from
the supply rails while maintaining high open-loop gain. See
the typical performance curve "Output Voltage Swing vs
Output Current."

V+

Non-Inverting Gain

= V

V+

Inverting Amplifier

= V

V+

G = 1 Buffer

= V

FIGURE 3. Design Optimization with Rail-to-Rail Input Op Amps.

Rail-to-rail op amps can be used in virtually any op amp
configuration. To achieve optimum performance, how-
ever, applications using these special double-input-stage
op amps may benefit from consideration of their special
behavior.

In many applications, operation remains within the com-
mon-mode range of only one differential input pair.
However some applications exercise the amplifier through
the transition region of both differential input stages.
Although the two input stages are laser trimmed for
excellent matching, a small discontinuity may occur in
this transition. Careful selection of the circuit configura-
tion, signal levels and biasing can often avoid this transi-
tion region.

DESIGN OPTIMIZATION WITH RAIL-TO-RAIL INPUT OP AMPS

With a unity-gain buffer, for example, signals will traverse
this transition at approximately 1.3V below V+ supply
and may exhibit a small discontinuity at this point.

The common-mode voltage of the non-inverting ampli-
fier is equal to the input voltage. If the input signal always
remains less than the transition voltage, no discontinuity
will be created. The closed-loop gain of this configura-
tion can still produce a rail-to-rail output.

Inverting amplifiers have a constant common-mode volt-
age equal to V

. If this bias voltage is constant, no

discontinuity will be created. The bias voltage can gener-
ally be chosen to avoid the transition region.

FIGURE 4. Input Current Protection for Voltages Exceed-

ing the Supply Voltage.

OPA342

10mA max

V+

OUT

OVERLOAD

IN5818

Schottky diode is required only
if input voltage can go more
than 0.3V below ground.

CAPACITIVE LOAD AND STABILITY

The OPA342 in a unity-gain configuration can directly drive
up to 250pF pure capacitive load. Increasing the gain en-
hances the amplifier's ability to drive greater capacitive
loads. See the typical performance curve "Small-Signal

OPA342, 2342, 4342

Overshoot vs Capacitive Load." In unity-gain configura-
tions, capacitive load drive can be improved by inserting a
small (10

to 20

) resistor, R

, in series with the output, as

shown in Figure 5. This significantly reduces ringing while
maintaining dc performance for purely capacitive loads.
However, if there is a resistive load in parallel with the
capacitive load, a voltage divider is created, introducing a dc
error at the output and slightly reducing the output swing.
The error introduced is proportional to the ratio R

/ R

, and

is generally negligible.

FIGURE 6. OPA342 in Noninverting Configuration Driving ADS7822.

FIGURE 7. Speech Bandpass Filtered Data Acquisition System.

DRIVING A/D CONVERTERS

The OPA342 series op amps are optimized for driving
medium-speed sampling ADCs. The OPA342 op amps buffer
the ADC's input capacitance and resulting charge injection

while providing signal gain.

Figures 6 shows the OPA342 in a basic noninverting con-
figuration driving the ADS7822. The ADS7822 is a 12-bit,
micro-power sampling converter in the MSOP-8 package.
When used with the low-power, miniature packages of the
OPA342, the combination is ideal for space-limited, low-
power applications. In this configuration, an RC network at
the ADC's input can be used to filter charge injection.

Figure 7 shows the OPA2342 driving an ADS7822 in a
speech bandpass filtered data acquisition system. This small,
low-cost solution provides the necessary amplification and
signal conditioning to interface directly with an electret
microphone. This circuit will operate with V

= +2.7V to

+5V with less than 500

A quiescent current.

FIGURE 5. Series Resistor in Unity-Gain Configuration

Improves Capacitive Load Drive.

OPA342

V+

OUT

33pF

V+

GND

+IN

DCLOCK

Serial
Interface

1000pF

1.5k

20k

100k

150k

510k

51k

OUT

REF

V+ = +2.7V to 5V

CS/SHDN

1000pF

Electret

Microphone

(1)

G = 100

Passband 300Hz to 3kHz

NOTE: (1) Electret microphone
powered by R

ADS7822

12-Bit A/D

1/2

OPA2342

1/2

OPA2342

ADS7822

12-Bit A/D

DCLOCK

OUT

CS/SHDN

OPA342

+5V

V+

+In

REF

GND

Serial

Interface

0.1

NOTE: A/D Input = 0 to V

REF

= 0V to 5V for

0V to 5V output.

RC network filters high frequency noise.

500

3300pF

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