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INEAR
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ALD2711A/ALD2711B
ALD2711
DUAL MICROPOWER PRECISION RAIL-TO-RAIL CMOS OPERATIONAL AMPLIFIER
GENERAL DESCRIPTION
The ALD2711A/ALD2711B/ALD2711 is a dual monolithic CMOS
micropower precision high slew rate operational amplifier intended for
a broad range of analog applications using
±1V
to
±5V
dual power
supply systems, as well as +2V to +10V battery operated systems. All
device characteristics are specified for +5V single supply or
±2.5V
dual supply systems. Typical supply current is 200µA at 5V supply
voltage. It is manufactured with Advanced Linear Devices' enhanced
ACMOS silicon gate CMOS process.
The ALD2711A/ALD2711B/ALD2711 has been developed specifically
for the +5V single supply or
±1V
to
±5V
dual supply user and has an
input stage that operates to +300mV above and -300mV below the
supply voltages with no adverse effects and/or phase reversals.
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 at the positive and
negative supply voltages. This feature allows numerous analog serial
stages and flexibility in input signal bias levels. Second, each device
was designed to accommodate mixed applications where digital and
analog circuits may operate off the same power supply or battery.
Third, the output stage can typically drive up to 50pF capacitive and
10KΩ resistive loads.
These features, combined with extremely low input currents, high open
loop voltage gain, high useful bandwidth, and slew rate make the
LD2711A/ALD2711B/ALD2711 a versatile, micropower operational
amplifier.
The ALD2711A/ALD2711B/ALD2711 with on-chip offset voltage trimming
allows the device to be used without nulling in most applications.
Additionally, robust design and rigorous screening make this device
especially suitable for operation in temperature-extreme environments and
rugged conditions.
The unique characteristics of the ALD2711A/ALD2711B/ALD2711 are
modeled in an available macromodel.
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)
ALD2711ASAL
ALD2711BSAL
ALD2711SAL
8-Pin
Plastic Dip
Package
ALD2711APAL
ALD2711BPAL
ALD2711PAL
8-Pin
CERDIP
Package
ALD2711ADA
ALD2711BDA
ALD2711DA
FEATURES
• Designed and characterized for 5V operation
• Linear mode operation with input voltages
300mV beyond supply rails
• Output voltages to within 2mV of power supply
rails when driving a high impedance load
• Unity gain stable
• Extremely low input bias currents -- 0.01pA
• Dual power supply
±1.0V
to
±5.0V
• Single power supply +2V to +10V
• High voltage gain
• Output short circuit protected
• Unity gain bandwidth of 0.7MHz
• Slew rate of 0.7V/µs
• Low power dissipation
• Symmetrical complementary output drive
• Suitable for rugged, temperature-extreme
environments
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
V+
OUT
B
-IN
B
+IN
B
OUT
A
-IN
A
+IN
A
V-
1
2
3
4
TOP VIEW
SAL, PAL, DA PACKAGES
8
7
6
5
* Contact factory for leaded (non-RoHS) or high temperature versions.
Rev 2.1 ©2011 Advanced Linear Devices, Inc. 415 Tasman Drive, Sunnyvale, CA 94089-1706 Tel: (408) 747-1155 Fax: (408) 747-1286
www.aldinc.com
Design & Operating Notes:
1. The ALD2711A/ALD2711B/ALD2711 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 ALD2711A/ALD2711B/
ALD2711 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 ALD2711A/ALD2711B/ALD2711 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 ALD2711A/
ALD2711B/ALD2711 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 10
12
Ω
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 ALD2711A/ALD2711B/ALD2711 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 ALD2711A/ALD2711B/ALD2711, 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 0.2°C above ambient temperature under most operating
conditions.
TYPICAL PERFORMANCE CHARACTERISTICS
SUPPLY CURRENT AS A FUNCTION
OF SUPPLY VOLTAGE
INPUTS GROUNDED
OUTPUT UNLOADED
±7
COMMON MODE INPUT VOLTAGE RANGE
AS A FUNCTION OF SUPPLY VOLTAGE
±6
±5
±4
±3
±2
±1
0
T
A
= 25°C
+25°C
-25°C
COMMON MODE INPUT
VOLTAGE RANGE (V)
SUPPLY CURRENT (µA)
500
400
T
A
= -55°C
300
200
0
0
±1
±2
±3
±4
±5
±6
SUPPLY VOLTAGE (V)
+125°C
+70°C
0
±1
±2
±3
±4
±5
±6
±7
SUPPLY VOLTAGE (V)
OPEN LOOP VOLTAGE GAIN AS A
FUNCTION OF LOAD RESISTANCE
1000
INPUT BIAS CURRENT AS A FUNCTION
OF AMBIENT TEMPERATURE
1000
INPUT BIAS CURRENT (pA)
100
10
V
S
=
±2.5V
OPEN LOOP VOLTAGE
GAIN (V/mV)
100
1.0
10
V
S
=
±2.5V
T
A
= 25°C
1
10K
100K
1M
10M
0.1
0.01
-50
-25
0
25
50
75
100
125
LOAD RESISTANCE (Ω)
AMBIENT TEMPERATURE (°C)
ALD2711A/ALD2711B
ALD2711
Advanced Linear Devices
4 of 9
PCB Design
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