GENERAL DESCRIPTION
The ALD2706 is a dual monolithic CMOS micropower high slew-rate
operational amplifier intended for a broad range of analog applications
using ±1V to ±6V dual power supply systems, as well as +2V to +12V
battery operated systems. All device characteristics are specified for +5V
single supply or ±2.5V dual supply systems. Supply current is 80µA
maximum at 5V supply voltage. It is manufactured with Advanced Linear
Devices' enhanced A CMOS silicon gate CMOS process.
The ALD2706 is designed to offer a trade-off of performance parameters
providing a wide range of desired specifications. It offers the popular
industry standard pin configuration.
The ALD2706 has been developed specifically for the +5V single supply or
±1V to ±6V dual supply user. Several important characteristics of the
device make application easier to implement at those voltages. First, each
operational amplifier can operate with rail to rail input and output voltages.
This means the signal input voltage and output voltage can be equal to the
positive and negative supply voltages. This feature allows numerous
analog serial stages and flexibility in input signal bias levels. Secondly,
each device was designed to accommodate mixed applications where
digital and analog circuits may operate off the same power supply or
battery. Thirdly, the output stage can typically drive up to 25pF capacitive
and 20KΩ resistive loads. These features, combined with extremely low
input currents, high open loop voltage gain of 100V/mV, useful bandwidth
of 200KHz, a slew rate of 0.1V/µs, low offset voltage and temperature drift,
make the ALD2706 a versatile, micropower dual operational amplifier.
A typical ALD2706 has the capacity to process a 0.998V amplitude analog
signal with only 1.000V single supply voltage, while requiring only 0.1pA
input bias current.
DUAL ULTRA MICROPOWER RAIL-TO-RAIL CMOS OPERATIONAL AMPLIFIER
ALD2706A/ALD2706B
ALD2706
ADVANCED
LINEAR
DEVICES, INC.
FEATURES
• Typical 20µA supply current per amplifier
• All parameters specified for +5V single
supply or ±2.5V dual supply systems
• Rail-to-rail input and output voltage ranges
• Unity gain stable
• Extremely low input bias currents -- 0.1pA
• High source impedance applications
• Dual power supply ±1.0V to ±6.0V
• Single power supply +2V to +12V
• High voltage gain
• Unity gain bandwidth of 0.2MHz
• Slew rate of 0.1V/µs
• Symmetrical output drive
APPLICATIONS
• Voltage follower/buffer/amplifier
• Charge integrator
• Photodiode amplifier
• Data acquisition systems
• High performance portable
instruments
• Signal conditioning circuits
• Sensor and transducer amplifiers
• Low leakage amplifiers
• Active filters
• Sample/Hold amplifier
• Picoammeter
• Current to voltage converter
PIN CONFIGURATION
Operating Temperature Range
-55°C to +125°C0°C to +70°C0°C to +70°C
8-Pin 8-Pin 8-Pin
CERDIP Small Outline Plastic Dip
Package (SOIC) Package
ALD2706A DA ALD2706A SA ALD2706A PA
ALD2706B DA ALD2706B SA ALD2706B PA
ALD2706 DA ALD2706 SA ALD2706 PA
ORDERING INFORMATION
* Contact factory for industrial temperature range
2
3
4
8
7
5
TOP VIEW
DA, PA, SA PACKAGE
V-
OUT
A
-IN
A
+IN
A
+IN
B
-IN
B
OUT
B
V+
6
1
© 1998 Advanced Linear Devices, Inc. 415 T asman Drive, Sunnyvale, California 94089 -1706 Tel: (408) 747-1 155 Fax: (408) 747-1286 http://www .aldinc.com
ALD2706A/ALD2706B Advanced Linear Devices 2
ALD2706
Supply VS±1.0 ±6.0 ±1.0 ±6.0 ±1.0 ±6.0 V Dual Supply
Voltage V+2.0 12.0 2.0 12.0 2.0 12.0 V Single Supply
Input Offset VOS 2.0 5.0 10.0 mV RS ≤ 100KΩ
Voltage 2.8 5.8 11.0 mV 0°C ≤ TA ≤ +70°C
Input Offset IOS 0.1 20 0.1 20 0.1 20 pA TA = 25°C
Current 200 200 200 pA 0°C ≤ TA ≤ +70°C
Input Bias IB0.1 20 0.1 20 0.1 20 pA TA = 25°C
Current 200 200 200 pA 0°C ≤ TA ≤ +70°C
Input Voltage VIR -0.3 5.3 -0.3 5.3 -0.3 5.3 V V+ = +5
Range -2.8 2.8 -2.8 2.8 -2.8 2.8 V VS = ±2.5V
Input
Resistance RIN 1012 1012 1012 Ω
Input Offset
Voltage Drift TCVOS 7710µV/°CR
S ≤ 100KΩ
Power Supply PSRR 65 80 65 80 60 80 dB RS ≤ 100KΩ
Rejection Ratio 65 80 65 80 60 80 dB 0°C ≤ TA ≤ +70°C
Common Mode CMRR 65 83 65 83 60 83 dB RS ≤ 100KΩ
Rejection Ratio 65 83 65 83 60 83 dB 0°C ≤ TA ≤ +70°C
Large Signal AV10 100 10 100 5 80 V/mV RL = 100KΩ
Voltage Gain 300 300 300 V/mV RL ≥ 1MΩ
10 10 5 V/mV RL = 100KΩ
0°C ≤ TA ≤ +70°C
Output VO low 0.001 0.01 0.001 0.01 0.001 0.01 V RL = 1MΩ V+ = +5V
Voltage VO high 4.99 4.999 4.99 4.999 4.99 4.999 V 0°C ≤ TA ≤ +70°C
Range VO low -2.40 -2.25 -2.40 -2.25 -2.40 -2.25 V R L = 100KΩ
VO high 2.25 2.40 2.25 2.40 2.25 2.40 V 0°C ≤ TA ≤ +70°C
Output Short
Circuit Current ISC 200 200 200 µA
Supply Current IS50 80 50 80 50 80 µAV
IN=0V
No Load
Power Both amplifiers
Dissipation PD400 400 400 µWV
S = ±2.5V
OPERATING ELECTRICAL CHARACTERISTICS
TA = 25°C VS = ±2.5V unless otherwise specified
2706A 2706B 2706 Test
Parameter Symbol Min Typ Max Min Typ Max Min Typ Max Unit Conditions
ABSOLUTE MAXIMUM RATINGS
Supply voltage, V+ 13.2V
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
ALD2706A/ALD2706B Advanced Linear Devices 3
ALD2706
VS = ± 2.5V -55°C ≤ TA ≤ +125°C unless otherwise specified
Input Offset
Voltage VOS 3.0 6.0 12.0 mV RS ≤ 100KΩ
Input Offset
Current IOS 4.0 4.0 4.0 nA
Input Bias
Current IB4.0 4.0 4.0 nA
Power Supply
Rejection Ratio PSRR 60 75 60 75 60 75 dB RS ≤ 1MΩ
Common Mode
Rejection Ratio CMRR 60 83 60 83 60 83 dB RS ≤ 1MΩ
Large Signal
Voltage Gain AV10 50 10 50 5 50 V/mV RL = 1MΩ
Output Voltage VO low -2.40 -2.25 -2.40 -2.25 -2.40 -2.25 V
Range VO high 2.25 2.40 2.25 2.40 2.25 2.40 V RL = 1MΩ
2706A DA 2706B DA 2706 DA Test
Parameter Symbol Min Typ Max Min Typ Max Min Typ Max Unit Conditions
Input
Capacitance CIN 111pF
Bandwidth BW200 200 200 KHz
Slew Rate SR0.1 0.1 0.1 V/µsA
V = +1
RL = 100KΩ
Rise time tr1.0 1.0 1.0 µsR
L = 100KΩ
Overshoot 20 20 20 % RL = 100KΩ
Factor CL = 25pF
Settling 10.0 10.0 10.0 µs 0.1%
Time tsAV = -1
CL = 25pF RL = 100KΩ
Channel
Separation CS140 140 140 dB AV = 100
Power Supply
Rejection Ratio PSRR 80 80 80 dB RS ≤ 1MΩ
Common Mode
Rejection Ratio CMRR 80 80 80 dB RS ≤ 1MΩ
Large Signal
Voltage Gain AV50 50 50 V/mV RL = 1MΩ
Output Voltage VO low -0.95 -0.9 -.95 -0.9 -0.95 -0.9 V RL = 1MΩ
Range VO high 0.9 0.95 0.9 0.95 0.9 0.95 V
Bandwidth BW0.2 0.2 0.2 MHz
Slew Rate SR0.1 0.1 0.1 V/µsA
V =+1
CL = 25pF
TA = 25°C VS = ±1.0V unless otherwise specified
2706A 2706B 2706 Test
Parameter Symbol Min Typ Max Min Typ Max Min Typ Max Unit Conditions
OPERATING ELECTRICAL CHARACTERISTICS (cont'd)
TA = 25°C VS = ±2.5V unless otherwise specified
2706A 2706B 2706 Test
Parameter Symbol Min Typ Max Min Typ Max Min Typ Max Unit Conditions
ALD2706A/ALD2706B Advanced Linear Devices 4
ALD2706
Design & Operating Notes:
1. The ALD2706 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 ALD2706 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.
2. The ALD2706 has complementary p-channel and n-channel input
differential stages connected in parallel to accomplish rail to rail
input common mode voltage range. 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 below the
positive supply voltage. Since offset voltage trimming on the
ALD2706 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
above 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 provision in his
design to allow for input offset voltage variations.
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 1012Ω 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.
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.
5. The ALD2706 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 to not exceed 0.3V of
the power supply voltage levels.
6. The ALD2706, with its micropower operation, offers numerous
benefits in reduced power supply requirements, less noise coupling
and current spikes, less thermally induced drift, better overall
reliability due to lower self heating, and lower input bias current. It
requires practically no warm up time as the chip junction heats up
to only 0.1°C above ambient temperature under most operating
conditions.
TYPICAL PERFORMANCE CHARACTERISTICS
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 1255025-50
10000
V
S
= ±2.5V
OPEN LOOP VOLTAGE GAIN AS A
FUNCTION OF LOAD RESISTANCE
10M
LOAD RESISTANCE (Ω)
10K 100K 1M
1000
100
10
1
OPEN LOOP VOLTAGE
GAIN (V/mV)
V
S
= ±2.5V
T
A
= 25°C
SUPPLY CURRENT AS A FUNCTION
OF SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
160
120
40
80
0
SUPPLY CURRENT (µA)
0±1±2±3±4±5±6
T
A
= -55°C -25°C
+25°C
+70°C+125°C
INPUTS GROUNDED
OUTPUT UNLOADED
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
±1
00 ±1 ±2 ±3 ±4 ±5 ±6 ±7
T
A
= 25°C
ALD2706A/ALD2706B Advanced Linear Devices 5
ALD2706
TYPICAL PERFORMANCE CHARACTERISTICS
OUTPUT VOLTAGE SWING AS A FUNCTION
OF SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
0±1±2±3±4±7±6±5
±6
±5
±4
±3
±2
±1
OUTPUT VOLTAGE SWING (V)
±25°C ≤ T
A
≤ +125°C
R
L
= 100KΩ
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
= ±2.5V
INPUT OFFSET VOLTAGE AS A FUNCTION
OF COMMON MODE INPUT VOLTAGE
COMMON MODE INPUT VOLTAGE (V)
-2 -1 0 +1 +3+2
15
10
5
-5
-10
0
-15
INPUT OFFSET VOLTAGE (mV)
V
S
= ±2.5V
T
A
= 25°C
SMALL - SIGNAL TRANSIENT
RESPONSE
100mV/div
50mV/div 10µs/div
V
S
= ±2.5V
T
A
= 25°C
R
L
= 100KΩ
C
L
= 25pF
OPEN LOOP VOLTAGE GAIN AS
A FUNCTION OF FREQUENCY
FREQUENCY (Hz)
1 10 100 1K 10K 1M 10M100K
120
100
80
60
40
20
0
-20
OPEN LOOP VOLTAGE
GAIN (dB)
V
S
= ±2.5V
T
A
= 25°C
90
0
45
180
135
PHASE SHIFT IN DEGREES
LARGE - SIGNAL TRANSIENT
RESPONSE
V
S
= ±1.0V
T
A
= 25°C
R
L
= 100KΩ
C
L
= 25pF
2V/div
500mV/div 10µs/div
LARGE - SIGNAL TRANSIENT
RESPONSE
2V/div 10µs/div
5V/div V
S
= ±2.5V
T
A
= 25°C
R
L
= 100KΩ
C
L
= 25pF
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
±55°C ≤ T
A
≤ +125°C
R
L
= 100KΩ
±8
ALD2706A/ALD2706B Advanced Linear Devices 6
ALD2706
TYPICAL APPLICATIONS
RAIL-TO-RAIL VOLTAGE FOLLOWER/BUFFER
HIGH INPUT IMPEDANCE RAIL-TO-RAIL PRECISION
DC SUMMING AMPLIFIER
LOW VOLTAGE INSTRUMENTATION AMPLIFIER
RAIL-TO-RAIL WINDOW COMPARATOR
RAIL-TO-RAIL WAVEFORM
Performance waveforms.
Upper trace is the output of a
Wien Bridge Oscillator. Lower
trace is the output of Rail-to-Rail
voltage follower.
0V
+5V
OUTPUT
0V
+5V
INPUT
PHOTO DETECTOR CURRENT TO
VOLTAGE CONVERTER
+
-+2.5V
-2.5V
R
F
= 5M
I
PHOTODIODE
V
OUT
= 1 X R
F
R
L
= 100K
1/2 ALD2706
HIGH IMPEDANCE NON-INVERTING AMPLIFIER
+
+1V
-1V
900K
100K
V
OUT
V
IN
1/2 ALD2706
-
+
OUTPUT
5V
0.1µF
* See Rail to Rail Waveform
0≤ V
IN
≤ 5V
V
IN
Z
IN
= 10
12
Ω
~
1/2 ALD2706
V- = - 2.5V
10M
10M
10M
10M
10M
10M
RIN = 10MΩ Accuracy limited by resistor tolerances and input offset voltage
V+ = +2.5V
-
+
0.1µF
0.1µFVOUT
V- ≤ VOUT ≤ V+
V1
V4
V3
V2
VOUT = V1 + V2 - V3 - V4
R1
50K
100K
R3
100K
f max = 20KHz
-40mV ≤ V
IN
≤ 40mV
0.1µF
0.1µF
V+
V-
-
+
-
+
R2
100K
100K
-
R4
500K
0.1µF V+
V+ 1M
+
1M V-
V- 0.1µF
V
OUT
1/2 ALD2706
1/2 ALD2706
1/2 ALD2706 V+ = +1.0V
V- = -1.0V
V- ≤ V
OUT
≤ V+
All resistors are 1%.
R1 R3
V
OUT
= V
IN
( 1+ 2R2 ) (R4)
= 25 V
IN
+5V
+
-
+
-
V
IN
100K
V
REF
(HIGH)
V
REF
(LOW)
3
2
5
6
8
4
1
7
1/4 74 C00
1/2 ALD2706
V
OUT
V
OUT (LOW)
FOR V
REF (LOW)
<
V
IN
< V
REF(HIGH)
100K
1/2 ALD2706
