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ALD1701A/ALD1701B
ALD1701/ALD1701G
MICROPOWER RAIL-TO-RAIL CMOS OPERATIONAL AMPLIFIER
GENERAL DESCRIPTION
The ALD1701 is a 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 250µA maximum at 5V
supply voltage. It is manufactured with Advanced Linear Devices' en-
hanced ACMOS silicon gate CMOS process.
The ALD1701 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 of
µA741
and ICL7611 types.
The ALD1701 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, the 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, the 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 50pF capacitive
and 10KΩ resistive loads.
These features, combined with extremely low input currents, high open
loop voltage gain of 100V/mV, useful bandwidth of 700KHz, a slew rate of
0.7V/µs, low power dissipation of 0.5mW, low offset voltage and tempera-
ture drift, make the ALD1701 a versatile, micropower operational amplifier.
The ALD1701, designed and fabricated with silicon gate CMOS techno-
logy, offers 1pA typical input bias current. On chip offset voltage trimming
allows the device to be used without nulling in most applications.
FEATURES
• All parameters specified for +5V single
supply or
±2.5V
dual supply systems
• Rail to rail input and output voltage ranges
• No frequency compensation required --
unity gain stable
• Extremely low input bias currents --
1.0pA typical (30pA max.)
• Ideal for high source impedance
applications
• Dual power supply
±1.0V
to
±6.0V
operation
• Single power supply +2V to +12V operation
• High voltage gain -- typically 100V/mV
@
±2.5V(100dB)
• Drive as low as 10KΩ load
• Output short circuit protected
• Unity gain bandwidth of 0.7MHz
• Slew rate of 0.7V/µs
• Low power dissipation
APPLICATIONS
•
•
•
•
•
•
•
•
•
•
•
•
•
Voltage amplifier
Voltage follower/buffer
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
ORDERING INFORMATION
Operating Temperature Range
-55°C to +125°C
0°C to +70°C
0°C to +70°C
8-Pin
CERDIP
Package
ALD1701A DA
ALD1701B DA
ALD1701 DA
ALD1701G DA
8-Pin
Small Outline
Package (SOIC)
ALD1701A SA
ALD1701B SA
ALD1701 SA
ALD1701G SA
8-Pin
Plastic Dip
Package
ALD1701A PA
ALD1701B PA
ALD1701 PA
ALD1701G PA
N/C
-IN
+IN
V-
1
2
3
4
TOP VIEW
DA, PA, SA PACKAGE
* N/C Pin is internally connected. Do not connect externally.
8
2
7
6
5
N/C
V+
OUT
N/C
* 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
Design & Operating Notes:
1. The ALD1701 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 opera-
tional amplifier. The ALD1701 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 ALD1701 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 compa-
tibility 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 ALD1701 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 excur-
sions 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 transis-
tors 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 ALD1701 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.
6. The ALD1701, with its micropower operation, offers numerous
benefits in reduced power supply requirements, less noise coupling
and current spikes, less thermally induced drift, better overall reli-
ability 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 condi-
tions.
TYPICAL PERFORMANCE CHARACTERISTICS
SUPPLY CURRENT AS A FUNCTION
OF SUPPLY VOLTAGE
±500
COMMON MODE INPUT VOLTAGE RANGE
AS A FUNCTION OF SUPPLY VOLTAGE
±7
±6
±5
±4
±3
±2
±1
0
T
A
= 25°C
SUPPLY CURRENT (µA)
±400
±300
±200
T
A
= -55°C
+70°C
±100
0
0
±1
±2
±3
±4
±5
±6
SUPPLY VOLTAGE (V)
+125°C
COMMON MODE INPUT
VOLTAGE RANGE (V)
INPUTS GROUNDED
OUTPUT UNLOADED
+25°C
-25°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
10000
INPUT BIAS CURRENT (pA)
OPEN LOOP VOLTAGE
GAIN (V/mV)
1000
100
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)
ALD1701A/ALD1701B
ALD1701/ALD1701G
Advanced Linear Devices
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