DUAL RAIL-TO-RAIL CMOS OPERATIONAL AMPLIFIER
A
DVANCED
L
INEAR
D
EVICES,
I
NC.
ALD2704A/ALD2704B
ALD2704
GENERAL DESCRIPTION
The ALD2704 is a dual monolithic operational amplifier with MOSFET
input that has rail-to-rail input and output voltage ranges. The input
voltage range and output voltage range are very close to the positive and
negative power supply voltages. Typically the input voltage can be
beyond positive power supply voltage V+ or the negative power supply
voltage V- by up to 300mV. The output voltage swings to within 60mV of
either positive or negative power supply voltages at rated load.
With high impedance load, the output voltage of the ALD2704 ap-
proaches within 1mV of the power supply rails. This device is designed
as an alternative to the popular J-FET input operational amplifier in
applications where lower operating voltages, such as 9V battery or
3.25V
to
6V power supplies are being used. The ALD2704 offers high slew rate
of 5V/
s. It is designed and manufactured with Advanced Linear Devices'
standard enhanced ACMOS silicon gate CMOS process, and it offers low
unit cost and exceptional reliability.
The rail-to-rail input and output feature of the ALD2704 expands signal
voltage range for a given operating supply voltage and allows numerous
analog serial stages to be implemented without losing operating voltage
margin. The output stage is designed to drive up to 10mA into 400pF
capacitive and 1.5K
resistive loads at unity gain and up to 4000pF at a
gain of 5. Short circuit protection to either ground or the power supply rails
is at approximately 15mA clamp current. Due to complementary output
stage design, the output can source and sink 10mA into a load with
symmetrical drive and is ideally suited for applications where push-pull
voltage drive is desired.
For each of the operational amplifier, the offset voltage is trimmed on-chip
to eliminate the need for external nulling in many applications. For
precision applications, the output is designed to settle to 0.1% in 2
s. In
large signal buffer applications, the operational amplifier can function as
an ultrahigh input impedance voltage follower /buffer that allows input and
output voltage swings from positive to negative supply voltages. This
feature is intended to greatly simplify systems design and eliminate higher
voltage power supplies in many applications.
FEATURES
Rail-to-rail input and output voltage ranges
Symmetrical push-pull output drives
Output settles to 2mV of supply rails
5.0V/
s slew rate
High capacitive load capability -- up to 4000pF
No frequency compensation required -- unity
gain stable
Extremely low input bias currents -- <1.0pA
typical (20pA max.)
Ideal for high source impedance applications
High voltage gain -- typically 100V/mV
Output short circuit protected
Unity gain bandwidth of 2.1MHz
APPLICATIONS
Voltage amplifier
Voltage follower/buffer
Charge integrator
Photodiode amplifier
Data acquisition systems
High performance portable instruments
Signal conditioning circuits
Low leakage amplifiers
Active filters
Sample/Hold amplifier
Picoammeter
Current to voltage converter
Coaxial cable driver
Capacitive sensor amplifier
Piezoelectric transducer amplifier
PIN CONFIGURATION
1
2
3
4
8
7
6
5
TOP VIEW
DA, PA, SA PACKAGE
OUT
A
-IN
A
+IN
A
V+
-IN
B
+IN
B
V -
OUT
B
Operating Temperature Range*
-55
C to +125
C
0
C to +70
C
0
C to +70
C
8-Pin
8-Pin
8-Pin
CERDIP
Small Outline
Plastic Dip
Package
Package (SOIC)
Package
ALD2704A DA
ALD2704A SA
ALD2704A PA
ALD2704B DA
ALD2704B SA
ALD2704B PA
ALD2704 DA
ALD2704 SA
ALD2704 PA
ORDERING INFORMATION
* Contact factory for industrial temperature range
1998 Advanced Linear Devices, Inc. 415 Tasman Drive, Sunnyvale, California 94089 -1706 Tel: (408) 747-1155 Fax: (408) 747-1286 http://www.aldinc.com
ALD2704A/ALD2704B
Advanced Linear Devices
2
ALD2704
ABSOLUTE MAXIMUM RATINGS
Supply voltage, V
+
referenced to V
-
-0.3V to V++13.2V
Supply voltage, V
S
referenced to V
-
6.6V
Differential input voltage range
-0.3V to V+
+0.3V
Power dissipation
600 mW
Operating temperature range PA, SA package
0
C to +70
C
DA package
-55
C to +125
C
Storage temperature range
-65
C to +150
C
Lead temperature, 10 seconds
+260
C
Supply
V
S
3.25
6.0
3.25
6.0
3.25
6.0
V
Dual Supply
Voltage
V
+
6.5
12.0
6.5
12.0
6.5
12.0
V
Single Supply
Input Offset
V
OS
1.0
2.0
5.0
mV
R
S
100K
Voltage
1.5
3.0
6.0
mV
0
C
T
A
+70
C
Input Offset
I
OS
1.0
15
1.0
15
1.0
15
pA
T
A
= 25
C
Current
240
240
240
pA
0
C
T
A
+70
C
Input Bias
I
B
1.0
20
1.0
20
1.0
20
pA
T
A
= 25
C
Current
300
300
300
pA
0
C
T
A
+70
C
Input Voltage
V
IR
-5.3
5.3
-5.3
5.3
-5.3
5.3
V
Range
Input
R
IN
10
12
10
12
10
12
Resistance
Input Offset
TCV
OS
5
5
5
V/
C
R
S
100K
Voltage Drift
Power Supply
PSRR
65
80
65
80
60
80
dB
R
S
100K
Rejection Ratio
0
C
T
A
+70
C
Common Mode
CMRR
65
83
65
83
60
83
dB
R
S
100K
Rejection Ratio
0
C
T
A
+70
C
Large Signal
A
V
15
28
15
28
10
28
V/mV
R
L
= 100K
Voltage Gain
100
100
100
V/mV
R
L
1M
Output
V
O
low
-4.96
-4.90
-4.96 -4.90
-4.96
-4.90
R
L
10K
Voltage
V
O
high
4.90
4.95
4.90
4.95
4.90 4.95
V
0
C
T
A
+70
C
Range
V
O
low
-4.998 -4.99
-4.998 -4.99
-4.998 -4.99
R
L
= 1M
V
O
high
4.99
4.998
4.99
4.998
4.99
4.998
V
0
C
T
A
+70
C
Output Short
I
SC
15
15
15
mA
Circuit Current
Supply
I
S
5.0
6.5
5.0
6.5
5.0
6.5
mA
V
IN
= -5V
Current
No Load
Power
P
D
65
65
65
mW
Both amplifiers, No Load
Dissipation
V
S
=
5.0V
Input
C
IN
1
1
1
pF
Capacitance
Bandwidth
B
W
2.1
2.1
2.1
MHz
Slew Rate
S
R
5.0
5.0
5.0
V/
s
A
V
= +1 R
L
= 2.0K
Rise time
t
r
0.1
0.1
0.1
s
R
L
= 2.0K
Overshoot
15
15
15
%
R
L
= 2.0K
Factor
C
L
= 100pF
OPERATING ELECTRICAL CHARACTERISTICS
T
A
= 25
C V
S
=
5.0V unless otherwise specified
2704A 2704B 2704
Test
Parameter
Symbol
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
Unit
Conditions
ALD2704A/ALD2704B
Advanced Linear Devices
3
ALD2704
Maximum Load
C
L
400
400
400
pF
Gain = 1
Capacitance
4000
4000
4000
pF
Gain = 5
Input Noise
e
n
26
26
26
nV/
Hz
f =1KHz
Voltage
Input Current
i
n
0.6
0.6
0.6
fA/
Hz
f =10Hz
Noise
Settling
t
s
5.0
5.0
5.0
s
0.01%
Time
2.0
2.0
2.0
s
0.1% A
V
= 1
R
L
= 5K
C
L
= 50pF
OPERATING ELECTRICAL CHARACTERISTICS (cont'd)
T
A
= 25
C V
S
=
5.0V unless otherwise specified
2704A
2704B
2704
Parameter
Symbol
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
Unit
Test Conditions
Input Offset
V
OS
2.0
4.0
7.0
mV
R
S
100K
Voltage
Input Offset
I
OS
8.0
8.0
8.0
nA
Current
Input Bias
I
B
10.0
10.0
10.0
nA
Current
Power Supply
PSRR
60
75
60
75
60
75
dB
R
S
100K
Rejection Ratio
Common Mode
CMRR
60
83
60
83
60
83
dB
R
S
100K
Rejection Ratio
Large Signal
AV
10
25
10
25
10
25
V/mV
R
L
= 10K
Voltage Gain
Output Voltage
V
O
low
-4.9
-4.8
-4.9
-4.8
-4.9
-4.8
Range
V
O
high
4.8
4.9
4.8
4.9
4.8
4.9
V
R
L
= 10K
V
S
=
5.0V -55
C
T
A
+125
C unless otherwise specified
2704ADA
2704BDA
2704DA
Parameter
Symbol
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
Unit
Test Conditions
ALD2704A/ALD2704B
Advanced Linear Devices
4
ALD2704
Design & Operating Notes:
1. The ALD2704 CMOS operational amplifier uses a 3 gain stage
architecture and an improved frequency compensation scheme to
achieve large voltage gain, high output driving capability, and better
frequency stability. The ALD2704 is internally compensated for unity
gain stability using a novel scheme. This design produces a clean
single pole roll off in the gain characteristics while providing for more
than 70 degrees of phase margin at the unity gain frequency. A unity
gain buffer using the ALD2704 will typically drive 400pF of external
load capacitance without stability problems. In the inverting unity gain
configuration, it can drive up to 800pF of load capacitance. Compared
to other CMOS operational amplifiers, the ALD2704 is much more
resistant to parasitic oscillations.
2. The ALD2704 has complementary p-channel and n-channel input
differential stages connected in parallel to accomplish rail to rail input
common mode voltage range. With the common mode input voltage
close to the power supplies, one of the two differential stages is
switched off internally. To maintain compatibility with other opera-
tional amplifiers, this switching point has been selected to be about
1.5V above the negative supply voltage. As offset voltage trimming
on the ALD2704 is made when the input voltage is symmetrical to the
supply voltages, this internal switching does not affect a large variety
of applications such as an inverting amplifier or non-inverting amplifier
with a gain greater than 2 (10V operation), where the common mode
voltage does not make excursions below this switching point.
3. The input bias and offset currents are essentially input protection
TYPICAL PERFORMANCE CHARACTERISTICS
diode reverse bias leakage currents, and are typically less than 1pA
at room temperature. This low input bias current assures that the
analog signal from the source will not be distorted by input bias
currents. For applications where source impedance is very high, it
may be necessary to limit noise and hum pickup through proper
shielding.
4. The output stage consists of class AB complementary output drivers,
capable of driving a low resistance load. The output voltage swing is
limited by the drain to source on-resistance of the output transistors as
determined by the bias circuitry, and the value of the load resistor. The
voltage follower configuration, the oscillation and resistant with the
rail- to-rail input and output feature, makes the ALD2704 an effective
analog signal buffer for medium to high source impedance sensors,
transducers, and other circuit networks.
5. The ALD2704 operational amplifier has been designed to provide
static discharge protection. Internally, the design has been carefully
implemented to minimize latch up. However, care must be exercised
when handling the device to avoid strong static fields. In using the
operational amplifier, the user is advised to power up the circuit before,
or simultaneously with, any input voltages applied and to limit input
voltages to not exceed 0.3V of the power supply voltage levels.
Alternatively, a 100K
or higher value resistor at the input terminals
will limit input currents to acceptable levels while causing very small
or negligible accuracy effects.
OPEN LOOP VOLTAGE GAIN AS A FUNCTION
OF SUPPLY VOLTAGE AND TEMPERATURE
SUPPLY VOLTAGE (V)
1000
100
10
1
OPEN LOOP VOLTAGE
GAIN (V/mV)
0
2
4
6
RL = 10K
R
L
= 5K
} -55
C
} +25
C
} +125
C
8
INPUT BIAS CURRENT AS A FUNCTION
OF AMBIENT TEMPERATURE
AMBIENT TEMPERATURE (
C)
1000
100
10
0.1
1.0
INPUT BIAS CURRENT (pA)
100
-25
0
75
125
50
25
-50
V
S
=
5.0V
10000
SUPPLY CURRENT AS A FUNCTION
OF SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
0
SUPPLY CURRENT (mA)
0
1
2
3
4
5
6
INPUTS GROUNDED
OUTPUT UNLOADED
+80
C
+25
C
T
A
= -55
C
-25
C
7
1
2
3
4
5
6
7
8
+125
C
COMMON MODE INPUT VOLTAGE RANGE
AS A FUNCTION OF SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
COMMON MODE INPUT
VOLTAGE RANGE (V)
7
6
5
4
3
2
2
3
4
5
6
7
T
A
= 25
C
ALD2704A/ALD2704B
Advanced Linear Devices
5
ALD2704
TYPICAL PERFORMANCE CHARACTERISTICS
OPEN LOOP VOLTAGE AS A FUNCTION
OF FREQUENCY
FREQUENCY (Hz)
1
10
100
1K
10K
1M
10M
100K
120
100
80
60
40
20
0
-20
OPEN LOOP VOLTAGE
GAIN (dB)
90
0
45
180
135
PHASE SHIFT IN DEGREES
V
S
=
5.0V
T
A
= 25
C
LARGE - SIGNAL TRANSIENT
RESPONSE
V
S
=
5.0V
T
A
= 25
C
R
L
= 1K
C
L
= 50pF
5V/div
5V/div
2
s/div
SMALL - SIGNAL TRANSIENT
RESPONSE
V
S
=
5.0V
T
A
= 25
C
R
L
= 1.0K
C
L
= 50pF
100mV/div
50mV/div
1
s/div
OPEN LOOP VOLTAGE GAIN AS A
FUNCTION OF LOAD RESISTANCE
LOAD RESISTANCE (
)
1K
10K
1000K
100K
1000
100
10
1
OPEN LOOP VOLTAGE
GAIN (V/mV)
V
S
=
5.0V
T
A
= 25
C
INPUT OFFSET VOLTAGE AS A FUNCTION
OF COMMON MODE INPUT VOLTAGE
COMMON MODE INPUT VOLTAGE (V)
-4
-2
0
+2
+4
+6
15
10
5
0
-5
-10
-15
INPUT OFFSET VOLTAGE (mV)
V
S
=
5.0V
T
A
= 25C
RL = 10K
OUTPUT VOLTAGE SWING AS A
FUNCTION OF SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
OUTPUT VOLTAGE SWING (V)
3
0
1
2
3
4
5
6
7
R
L
= 2K
6
5
4
2
7
25
C
T
A
125
C
R
L
= 10K
INPUT OFFSET VOLTAGE AS A FUNCTION
OF AMBIENT TEMPERATURE
REPRESENTATIVE UNITS
AMBIENT TEMPERATURE (
C)
INPUT OFFSET VOLTAGE (mV)
-50
-25
0
+25
+50
+75
+100 +125
+4
+5
+3
+1
+2
0
-2
-1
-4
-3
-5
V
S
=
5.0V
VOLTAGE NOISE DENSITY AS A
FUNCTION OF FREQUENCY
FREQUENCY (Hz)
10
100
1K
10K
100K
150
125
100
75
50
25
0
1000K
VOLTAGE NOISE DENSITY
(nV/
Hz)
V
S
=
5.0V
T
A
= 25
C
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