e
ADVANCED
LINEAR
DEVICES, INC.
TM
EPAD
EN
®
AB
LE
D
ALD2732A/ALD2732
PRECISION DUAL LOW POWER CMOS OPERATIONAL AMPLIFIER
GENERAL DESCRIPTION
FEATURES & BENEFITS
The ALD2732A/ALD2732 is a precision dual low-cost low-power monolithic
CMOS operational amplifier intended for a broad range of precision applications requiring exremely low input signal power. Input signal power is the
product of input offset voltage and input bias current, which represents the
minimum required power draw from the signal source in order to drive the
input of the operational amplifier. Input signal power is also a figure of merit
in source loading and its associated error, and is a measure of the basic
signal resolution possible through the operational amplifier for a given signal
source. For certain types of signal sources, signal loading directly translates
into a significant distortion or "interface noise equivalent" term.
• Extremely low input offset voltages and
extremely low input bias currents
• Extremely low input signal power
• Robust high-temperature operation
• Industry standard pinout
• Rail-to-rail input/output
• Input bias current of 0.01pA at input
offset voltage of 25µV
• No external components
• No internal chopper clocking noise
• No chopper dynamic power dissipation
• Simple and cost effective
• Small package size
• Drive up to 4000pF load capacitance
• Low power dissipation
• Suitable for rugged, temperature-extreme
environments
Manufactured with Advanced Linear Devices' enhanced EPAD® silicon
gate CMOS process, the ALD2732A/ALD2732 is designed to set a new
standard in low input signal power requirements. The typical input loading
at its input is 0.03 mV offset voltage and 0.01 pA input bias current at 25C,
resulting in 0.0003 fW input signal power draw. This input characteristic
virtually eliminates any loading effects on most types of signal sources,
offering unparalled accuracy and signal integrity and fidelity. The
ALD2732A/ALD2732 is ideally suited for capacitive and high sensitivity,
high impedance signal sources. It is readily suited for +5V single supply (or
±2V to ±5V) systems, with low operating power dissipation, a traditional
strength of CMOS technology. It is offered with industry standard µA741 and
ICL7611 pin configurations.
The ALD2732A/ALD2732 can operate with rail to rail large signal input and
output voltages with relatively high slew rate. The input voltage can be equal
to or exceed the positive and negative supply voltages while the output
voltage can swing close to these supply voltage rails. This feature significantly reduces the supply overhead voltage required to operate the operational amplifier and allows numerous analog serial stages to operate in a low
power supply environment. In addition, the device can accommodate mixed
applications where digital and analog circuits may operate off the same
power supply or battery. This device also features rail-to-rail input and
output voltage ranges, tolerance to over-voltage input spikes of 300mV
beyond supply rails, high open loop voltage gain, useful bandwidth of
1.5MHz, slew rate of 2.1V/µs, and low supply current of 0.8mA. Finally, the
output stage can typically drive up to 400pF capacitive loads in the unity gain
mode and up to 4000pF capacitive loads at a gain of 5.
These features make the ALD2732A/ALD2732 a versatile, high precision
operational amplifier that is user friendly and easy to use with virtually no
source loading and zero input-loading induced source errors. Additionally,
robust design and rigorous screening make this device especially suitable
for operation in temperature-extreme environments and rugged conditions.
APPLICATIONS
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Precision cable driver
Sensor interface circuits
Unity gain buffer amplifier
Precision analog cable driver
Transducer biasing circuits
Capacitive and charge integration circuits
Biochemical probe interface
Signal conditioning
Portable instruments
High source impedance electrode
amplifiers
Precision Sample and Hold amplifiers
Precision current to voltage converter
Error correction circuits
Sensor compensation circuits
Precision gain amplifiers
System output level shifter
PIN CONFIGURATION
OUT A
1
8
V+
-IN A
2
7
OUT B
+IN A
3
6
-IN B
V-
4
5
+IN B
ORDERING INFORMATION (“L” suffix denotes lead-free (RoHS))
Operating Temperature Range
0°C to +70°C
0°C to +70°C
-55°C to +125°C
8-Pin
Small Outline
Package (SOIC)
8-Pin
Plastic Dip
Package
8-Pin
CERDIP
Package
ALD2732ASAL
ALD2732SAL
ALD2732APAL
ALD2732PAL
ALD2732ADA
ALD2732DA
TOP VIEW
SAL, PAL, DA PACKAGES
* Contact factory for leaded (non-RoHS) or high temperature versions.
©2014 Advanced Linear Devices, Inc., Vers. 2.0
www.aldinc.com
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ABSOLUTE MAXIMUM RATINGS
Supply voltage, V+
Differential input voltage range
Power dissipation
Operating temperature range SAL, PAL packages
DA package
Storage temperature range
Lead temperature, 10 seconds
CAUTION: ESD Sensitive Device. Use static control procedures in ESD controlled environment.
10.6V
-0.3V to V+ +0.3V
600mW
0°C to +70°C
-55°C to +125°C
-65°C to +150°C
+260°C
OPERATING ELECTRICAL CHARACTERISTICS
TA = 25°C VS = ±2.5V unless otherwise specified
Parameter
ALD2732A
Typ
Min
±5.0
10.0
±2.0
4.0
Max
Unit
Test
Conditions
±5.0
10.0
V
V
Dual Supply
Single Supply
2.0
mV
RS ≤ 100KΩ
0.01
10
280
pA
pA
TA = 25°C
0°C ≤ TA ≤ +70°C
0.01
10
280
pA
pA
TA = 25°C
0°C ≤ TA ≤ +70°C
+5.3
+2.8
V
V
V+ = +5V
VS = ±2.5V
Min
Supply Voltage
VS
V+
±2.0
4.0
Input Offset Voltage
VOS
0.5
1.0
1.0
Input Offset Current
IOS
0.01
10
280
Input Bias Current
IB
0.01
10
280
Input Voltage Range
VIR
Input Resistance
RIN
Input Offset Voltage Drift
TCVOS
Power Supply Rejection Ratio
-0.3
-2.8
Max
ALD2732
Typ
Symbol
+5.3
+2.8
-0.3
-2.8
1014
1014
5
5
PSRR
85
Common Mode Rejection Ratio
CMRR
Large Signal Voltage Gain
AV
Output Voltage Range
VO low
VO high
4.99
VO low
VO high
2.35
Ω
µV/°C
RS ≤ 100KΩ
85
dB
RS ≤ 100KΩ
85
85
dB
RS ≤ 100KΩ
250
500
250
500
V/mV
V/mV
RL = 10KΩ
RL = 1MΩ
V
V
RL = 1MΩ, V+ = 5V
0°C ≤ TA ≤ +70°C
V
RL =10KΩ
0°C ≤ TA ≤ +70°C
0.002
4.999
0.01
-2.44
-2.35
4.99
2.44
2.35
0.01
-2.44
-2.35
2.44
V
Output Short Circuit Current
ISC
Supply Current
IS
2.4
3.5
2.4
3.5
mA
VIN = 0V, No Load
Power Dissipation
PD
12
17.5
12
17.5
mW
VS = ±2.5V
Input Capacitance
CIN
1
1
pF
Maximum Load
Capacitance
CL
400
4000
400
4000
pF
pF
Gain = 1
Gain = 5
Input Noise Voltage
en
26
26
nV/√Hz
f = 1KHz
Input Current Noise
in
0.6
0.6
fA/√Hz
f = 10Hz
Bandwidth
BW
1.0
1.5
1.0
1.5
MHz
Slew Rate
SR
1.4
2.1
1.4
2.1
V/µs
ALD2732A/ALD2732
8
0.002
4.999
8
Advanced Linear Devices
mA
AV = +1, RL = 10KΩ
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OPERATING ELECTRICAL CHARACTERISTICS (cont'd)
TA = 25°C VS = ±2.5V unless otherwise specified (cont'd)
ALD2732A
Parameter
Symbol
Rise time
tr
Min
Overshoot Factor
Settling Time
ts
ALD2732
Typ
Max
Min
Typ
Max
Unit
Test Conditions
0.2
0.2
µs
RL = 10KΩ
10
10
%
RL = 10KΩ,
CL = 100pF
8.0
3.0
8.0
3.0
µs
µs
0.01%
0.1%, AV = -1,
RL= 1MΩ,
CL = 25pF
TA = 25°C VS = ±5.0V unless otherwise specified
ALD2732A
Parameter
Symbol
Min
Power Supply Rejection Ratio
PSRR
85
Common Mode Rejection Ratio
CMRR
Large Signal Voltage Gain
AV
Output Voltage Range
VO low
VO high
4.80
Typ
ALD2732
Unit
Test Conditions
85
dB
RS ≤ 100KΩ
97
97
dB
RS ≤ 100KΩ
250
250
V/mV
RL = 10KΩ
V
RL = 10KΩ
-4.90
4.93
Max
Min
-4.80
4.80
Typ
-4.90
4.93
Max
-4.80
Bandwidth
BW
1.7
1.7
MHz
Slew Rate
SR
2.8
2.8
V/µs
AV = +1, CL = 50pF
VS = ±2.5V -55°C ≤ TA ≤ +125°C unless otherwise specified
ALD2732A
Symbol
Input Offset Voltage
VOS
Input Offset Current
IOS
Input Bias Current
IB
Power Supply Rejection Ratio
PSRR
85
85
dB
RS ≤ 100KΩ
Common Mode Rejection Ratio
CMRR
97
97
dB
RS ≤ 100KΩ
Large Signal Voltage Gain
AV
25
25
V/mV
RL = 10KΩ
Output Voltage Range
VO low
VO high
V
V
RL = 10KΩ
ALD2732A/ALD2732
Min
ALD2732
Parameter
2.30
Typ
Max
0.5
2.0
-2.40
2.40
Min
Typ
Max
Unit
Test Conditions
0.7
3.5
mV
RS ≤ 100KΩ
2.0
2.0
nA
2.0
2.0
nA
-2.30
2.30
Advanced Linear Devices
-2.40
2.40
-2.30
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Design & Operating Notes:
1. The ALD2732A/ALD2732 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. In a conventional CMOS operational amplifier
design, compensation is achieved with a pole splitting capacitor
together with a nulling resistor. This method is, however, very bias
dependent and thus cannot accommodate the large range of supply
voltage operation as is required from a stand alone CMOS operational
amplifier. The ALD2732A/ALD2732 is internally compensated for
unity gain stability using a novel scheme that does not use a nulling
resistor. This scheme 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
ALD2732A/ALD2732 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 ALD2732A/ALD2732 has
shown itself to be more resistant to parasitic oscillations.
3. The input bias and offset currents are essentially input protection
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. Normally, this extremely high input impedance of greater
than 1014Ω would not be a problem as the source impedance would
limit the node impedance. However, for applications where source
impedance is very high, it may be necessary to limit noise and hum
pickup through proper shielding.
2. The ALD2732A/ALD2732 has complementary p-channel and n-channel input differential stages connected in parallel to accomplish rail to
rail common mode input voltage ranges. This means that with the
ranges of common mode input voltage close to the power supplies,
one of the two differential stages is switched off internally. To maintain
compatibility with other operational amplifiers, this switching point has
been selected to be about 1.5V above the negative supply voltage.
Since offset voltage trimming on the ALD2732A/ALD2732 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 larger
than 2.5 (5V operation), where the common mode voltage does not
make excursions below this switching point. The user should however, be aware that this switching does take place if the operational
amplifier is connected as a unity gain buffer and should make
provisions in the design to allow for input offset voltage variations.
5. The ALD2732A/ALD2732 operational amplifier has been designed to
provide full 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 that
may degrade a diode junction, causing increased input leakage
currents. 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 not to exceed 0.3V of the power
supply voltage levels.
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.
When connected in the voltage follower configuration, the oscillation
resistant feature, combined with the rail to rail input and output feature,
makes an effective analog signal buffer for medium to high source
impedance sensors, transducers, and other circuit networks.
6. The ALD2732A/ALD2732 has an internal design architecture that
provides robust high temperature operation. Contact factory for
custom screening versions.
TYPICAL PERFORMANCE CHARACTERISTICS
COMMON MODE INPUT VOLTAGE RANGE
AS A FUNCTION OF SUPPLY VOLTAGE
SUPPLY CURRENT AS A FUNCTION
OF SUPPLY VOLTAGE
±6
INPUTS GROUNDED
OUTPUT UNLOADED
2.0
COMMON MODE INPUT
VOLTAGE RANGE (V)
SUPPLY CURRENT (mA)
2.5
1.5
TA = -55ºC
1.0
-25°C
0.5
+25°C
+80°C
+125°C
0
TA = 25°C
±4
±3
±2
±1
0
0
±1
±2
±3
±4
±5
±6
0
±1
±2
±3
±4
±5
±6
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
OPEN LOOP VOLTAGE GAIN AS A FUNCTION
OF SUPPLY VOLTAGE AND TEMPERATURE
INPUT BIAS CURRENT AS A FUNCTION
OF AMBIENT TEMPERATURE
1000
1000
INPUT BIAS CURRENT (pA)
OPEN LOOP VOLTAGE
GAIN (V/mV)
±5
-55°C {
100
+25°C {
+125°C {
10
RL= 10KΩ
RL= 5KΩ
100
VS = ±2.5V
10
1.0
0.1
0.01
1
0
±1
±2
±3
±4
±5
±6
ALD2732A/ALD2732
-50
-25
0
+25
+50
+75
+100
+125
AMBIENT TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
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TYPICAL PERFORMANCE CHARACTERISTICS (cont'd)
OUTPUT VOLTAGE SWING AS A
FUNCTION OF SUPPLY VOLTAGE
OPEN LOOP VOLTAGE GAIN AS A
FUNCTION OF LOAD RESISTANCE
1000
-55°C ≤ TA ≤ +125°C
OPEN LOOP VOLTAGE
GAIN (V/mV)
OUTPUT VOLTAGE SWING (V)
±6
±5
±4
RL = 10KΩ
±3
RL = 2KΩ
±2
100
±1
10
VS = ±2.5V
TA = 25°C
1
0
±1
±2
±3
±4
±5
1K
±6
10K
100K
1000K
SUPPLY VOLTAGE (V)
LOAD RESISTANCE (Ω)
OPEN LOOP VOLTAGE GAIN AS A
FUNCTION OF FREQUENCY
LARGE-SIGNAL TRANSIENT
RESPONSE
5V/div
100
VS = ±2.5V
TA = 25°C
80
60
0
40
45
20
90
0
135
-20
180
1
10
100
1K
10K
100K
1M
PHASE SHIFT IN DEGREES
OPEN LOOP VOLTAGE
GAIN (dB)
120
1V/div
VS = ±2.5V
TA = 25°C
RL = 100KΩ
CL = 50pF
2µs/div
10M
FREQUENCY (Hz)
SMALL-SIGNAL TRANSIENT
RESPONSE
100mV/div
VS = ±2.5V
TA = 25°C
RL = 10KΩ
CL = 50pF
20mV/div
ALD2732A/ALD2732
Advanced Linear Devices
2µs/div
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TYPICAL APPLICATIONS
RAIL-TO-RAIL VOLTAGE FOLLOWER/BUFFER
PHOTO DETECTOR CURRENT TO
VOLTAGE CONVERTER
RF = 5M
5V
~ 1012Ω
ZIN =
0.1µF
I
OUTPUT
+
VIN
1/2 ALD2732
0≤ VIN ≤ 5V
-2.5V
1/2 ALD2732
* See Rail to Rail Waveform
RAIL-TO-RAIL WAVEFORM
V+ = +2.5V
V2
RL = 100K
+
HIGH INPUT IMPEDANCE RAIL-TO-RAIL
PRECISION DC SUMMING AMPLIFIER
V1
INPUT
10M
+
10M
10M
10M
0.1µF
1/2 ALD2732
-
+5V
0V
+5V
OUTPUT
0V
VOUT
0.1µF
V3
VOUT = 1 X RF
+2.5V
-
PHOTODIODE
V- ≤ VIN ≤ V+
V4
10M
Performance waveforms.
Upper trace is the output of a
Wien Bridge Oscillator. Lower
trace is the output of Rail-to-rail
voltage follower.
V- ≤ VOUT ≤ V+
V- = - 2.5V
10M
VOUT = V1 + V2 - V3 - V4
RIN = 10MΩ Accuracy limited by resistor tolerances and input offset voltage
WIEN BRIDGE OSCILLATOR (RAIL-TO-RAIL)
SINE WAVE GENERATOR
RAIL-TO-RAIL WINDOW COMPARATOR
+5V
-
8
+2.5V
100K
VREF (HIGH) 3
1
VOUT
1/2 ALD2732
+
2
10K
-2.5V
.01µF
5
10K
100K
~
f=
-
+
7
10K
R = 10K
1/4 74 C00
VOUT
VIN
C = .01µF
1/2 ALD2732
+
VREF (LOW)
6 -
4
~ 1.6KHZ
1
=
2πRC
1/2 ALD2732
VOUT (LOW) FOR VREF (LOW) < VIN < VREF(HIGH)
* See Rail to Rail Waveform
LOW VOLTAGE INSTRUMENTATION AMPLIFIER
V+
0.1µF
1M
+
100K
-
500K
100K
V-
1/2 ALD2732
f max = 20KHz
-40mV ≤ VIN ≤ 40mV
V+
V+
0.1µF
0.1µF
+
50K
V+ 1M
0.1µF
VOUT
-
100K
1M
100K
V-
0.1µF
ALD1732
V-
1M
+
V-
0.1µF
1/2 ALD2732
ALD2732A/ALD2732
GAIN = 25 V- ≤ VOUT ≤ V+ All resistors are 1%
V+ = +1.0V V- = -1.0V Short Circuit Input Current 1µA
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SOIC-8 PACKAGE DRAWING
8 Pin Plastic SOIC Package
E
Millimeters
Dim
S (45°)
D
A
Min
1.35
Max
1.75
Min
0.053
Max
0.069
A1
0.10
0.25
0.004
0.010
b
0.35
0.45
0.014
0.018
C
0.18
0.25
0.007
0.010
D-8
4.69
5.00
0.185
0.196
E
3.50
4.05
0.140
0.160
1.27 BSC
e
A
A1
e
Inches
0.050 BSC
H
5.70
6.30
0.224
0.248
L
0.60
0.937
0.024
0.037
ø
0°
8°
0°
8°
S
0.25
0.50
0.010
0.020
b
S (45°)
H
L
ALD2732A/ALD2732
C
ø
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PDIP-8 PACKAGE DRAWING
8 Pin Plastic DIP Package
E
E1
Millimeters
D
S
A2
A1
e
b
b1
A
L
Inches
Dim
Min
Max
Min
Max
A
3.81
5.08
0.105
0.200
A1
0.38
1.27
0.015
0.050
A2
1.27
2.03
0.050
0.080
b
0.89
1.65
0.035
0.065
b1
0.38
0.51
0.015
0.020
c
0.20
0.30
0.008
0.012
D-8
9.40
11.68
0.370
0.460
E
5.59
7.11
0.220
0.280
E1
7.62
8.26
0.300
0.325
e
2.29
2.79
0.090
0.110
e1
L
7.37
7.87
0.290
0.310
2.79
3.81
0.110
0.150
S-8
1.02
2.03
0.040
0.080
0°
15°
0°
15°
ø
c
e1
ALD2732A/ALD2732
ø
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CERDIP-8 PACKAGE DRAWING
8 Pin CERDIP Package
E E1
Millimeters
D
A1
s
A
L
L2
b
b1
e
L1
Min
Inches
Dim
A
3.55
Max
5.08
0.140
Min
Max
0.200
A1
1.27
2.16
0.050
0.085
b
0.97
1.65
0.038
0.065
b1
0.36
0.58
0.014
0.023
C
0.20
0.38
0.008
0.015
D-8
--
10.29
--
0.405
E
5.59
7.87
0.220
0.310
E1
7.73
8.26
0.290
0.325
e
2.54 BSC
0.100 BSC
e1
7.62 BSC
0.300 BSC
L
3.81
5.08
0.150
0.200
L1
3.18
--
0.125
--
L2
0.38
1.78
0.015
0.070
S
--
2.49
--
0.098
Ø
0°
15°
0°
15°
C
e1
ALD2732A/ALD2732
ø
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