A
DVANCED
L
INEAR
D
EVICES,
I
NC.
ALD4706A/ALD4706B
ALD4706
DUAL ULTRA MICROPOWER RAIL-TO-RAIL CMOS OPERATIONAL AMPLIFIER
GENERAL DESCRIPTION
The ALD4706A/ALD4706B/ALD4706 is a quad monolithic CMOS ultra
micropower 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. Total supply current for four operational amplifiers is 200µA
maximum at 5V supply voltage. It is manufactured with Advanced Linear
Devices' enhanced ACMOS silicon gate CMOS process.
The ALD4706A/ALD4706B/ALD4706 is designed to offer a trade-off of
performance parameters providing a wide range of desired specifications.
It has been developed specifically for the +5V single supply or
±1V
to
±5V
dual supply user and offers the popular industry standard pin
configuration of LM324 types and ICL7641 types.
Several important characteristics of the device make application easier
to implement at these 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 or near to 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 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 0.17V/µs, low power dissipation of 0.5mW,
low offset voltage and temperature drift, make the ALD4706A/ALD4706B/
ALD4706 a versatile, ultra micropower quad operational amplifier.
The ALD4706A/ALD4706B/ALD4706, designed and fabricated with
silicon gate CMOS technology, offers 0.1pA typical input bias current.
Due to low voltage and low power operation, reliability and operating
characteristics, such as input bias currents and warm up time, are greatly
improved. Additionally, robust design and rigorous screening make this
device especially suitable for operation in temperature-extreme
environments and rugged conditions.
FEATURES
• 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
±5.0V
• Single power supply +2V to +10V
• High voltage gain
• Output short circuit protected
• Unity gain bandwidth of 0.2MHz
• Slew rate of 0.17V/µs
• Power dissipation of 20µA per op amp
• Symmetrical 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
OUT
A
1
2
14
13
12
11
10
9
8
OUT
D
-IN
D
+IN
D
V-
+IN
C
-IN
C
OUT
C
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
14-Pin
Small Outline
Package (SOIC)
ALD4706ASBL
ALD4706BSBL
ALD4706SBL
14-Pin
Plastic Dip
Package
ALD4706APBL
ALD4706BPBL
ALD4706PBL
14-Pin
CERDIP
Package
ALD4706ADB
ALD4706BDB
ALD4706DB
-IN
A
+IN
A
3
V+
4
+IN
B
5
-IN
B
OUT
B
6
7
* Contact factory for leaded (non-RoHS) or high temperature versions.
TOP VIEW
SBL, PBL, DB PACKAGES
Rev 2.0 ©2010 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 ALD4706A/ALD4706B/ALD4706 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 ALD4706A/ALD4706B/
ALD4706 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 ALD4706A/ALD4706B/ALD4706 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 ALD4706A/
ALD4706B/ALD4706 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 0.1pA
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
13
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 ALD4706A/ALD4706B/ALD4706 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 ALD4706A/ALD4706B/ALD4706, with its ultra 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
SUPPLY CURRENT AS A FUNCTION
OF SUPPLY VOLTAGE
INPUTS GROUNDED
OUTPUT UNLOADED
320
-25°C
240
160
80
0
0
±1
+70°C
±2
±3
±4
SUPPLY VOLTAGE (V)
+125°C
0
±7
±6
±5
±4
±3
±2
±1
T
A
= 25°C
COMMON MODE INPUT VOLTAGE RANGE
AS A FUNCTION OF SUPPLY VOLTAGE
SUPPLY CURRENT (µA)
T
A
= -55°C
COMMON MODE INPUT
VOLTAGE RANGE (V)
+25°C
±5
±6
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
10000
INPUT BIAS CURRENT (pA)
1000
100
OPEN LOOP VOLTAGE
GAIN (V/mV)
V
S
=
±2.5V
100
10
10
V
S
=
±2.5V
T
A
= 25°C
1
10K
100K
1M
10M
1.0
0.1
-50
-25
0
25
50
75
100
125
LOAD RESISTANCE (Ω)
AMBIENT TEMPERATURE (°C)
ALD4706A/ALD4706B
ALD4706
Advanced Linear Devices
4 of 9
Embedded System
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