A
DVANCED
L
INEAR
D
EVICES,
I
NC.
ALD4704A/ALD4704B
ALD4704
QUAD RAIL-TO-RAIL CMOS OPERATIONAL AMPLIFIER
GENERAL DESCRIPTION
The ALD4704 is a quad CMOS monolithic operational amplifier with
MOSFET input that has rail-to-rail input and output voltage ranges. The
input voltage can be beyond positive power supply voltage V+ or the
negative power supply voltage V- by up to 300mV. The output voltage
swings to within 60mV of either positive or negative power supply voltages
at rated load.
With high impedance load, the output voltage approaches to within 1mV
of the power supply rails. This device is designed as an alternative to the
popular J-FET input operational amplifiers in applications where lower
operating voltages, such as 9V battery or
±3.25V
to
±6V
power supplies
are being used. It offers high slew rate of 5V/µs at low operating power.
The ALD4704 is designed and manufactured with Advanced Linear
Devices' standard enhanced ACMOS silicon gate CMOS process for low
unit cost and exceptional reliability.
The rail-to-rail input and output feature of the ALD4704 expand signal
voltage range for a given operating supply voltage and allow numerous
analog serial stages to be implemented without losing operating voltage
margin. The output stage is designed to drive up to 10mA into 400pF
capacitive and 1.5KΩ resistive loads at unity gain and up to 4000pF at a
gain of 5. Short circuit protection to either ground or the power supply rails
is at approximately 15mA clamp current. The output can both source and
sink 10mA into a load with symmetrical drive and is ideally suited for
applications where push-pull voltage drive is desired.
For each of the operational amplifier, the offset voltage is trimmed on-chip
to eliminate the need for external nulling in many applications. For
precision applications, the output is designed to settle to 0.1% in 2µs. For
large signal buffer applications, the operational amplifier can function as
an ultrahigh input impedance voltage follower/buffer that allows input
and output voltage swings from positive to negative supply voltages. This
feature is intended to greatly simplify systems design and eliminate higher
voltage power supplies in many applications.
FEATURES
•
•
•
•
•
•
•
•
•
•
•
•
Rail-to-rail input and output voltage ranges
5.0V/µs slew rate
Symmetrical push-pull output drive
Inputs can extend beyond supply rails by
300mV
Outputs settle to 2mV of supply rails
High capacitive load capability -- up to
4000pF
No frequency compensation required –
unity gain stable
Extremely low input bias currents -- 1.0pA
typical (20pA max.)
Ideal for high source impedance applica-
tions
High voltage gain -- typically 100V/mV
Output short circuit protected
Unity gain bandwidth of 2.1MHz
APPLICATIONS
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Voltage amplifier
Voltage follower/buffer
Charge integrator
Photodiode amplifier
Data acquisition systems
High performance portable
instruments
Signal conditioning circuits
Low leakage amplifiers
Active filters
Sample/Hold amplifier
Picoammeter
Current to voltage converter
Coaxial cable driver
Capacitive sensor amplifier
Piezoelectric transducer amplifier
PIN CONFIGURATION
OUT
A
-IN
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
Operating Temperature Range*
-55°C to +125°C
0°C to +70°C
0°C to +70°C
14-Pin
CERDIP
Package
ALD4704A DB
ALD4704B DB
ALD4704 DB
14-Pin
Small Outline
Package (SOIC)
ALD4704A SB
ALD4704B SB
ALD4704 SB
14-Pin
Plastic Dip
Package
ALD4704A PB
ALD4704B PB
ALD4704 PB
+IN
A
3
V+
4
+IN
B
5
-IN
B
OUT
B
6
7
* Contact factory for industrial temperature range
DB, PB, SB Package
© 1998 Advanced Linear Devices, Inc. 415 Tasman Drive, Sunnyvale, California 94089 -1706 Tel: (408) 747-1155 Fax: (408) 747-1286 http://www.aldinc.com
ABSOLUTE MAXIMUM RATINGS
Supply voltage, V
+
referenced to V
-
Supply voltage, V
S
referenced to V
-
Differential input voltage range
Power dissipation
Operating temperature range PB, SB package
DB package
Storage temperature range
Lead temperature, 10 seconds
-0.3V to V++13.2V
±6.6V
+ +0.3V
-0.3V to V
600 mW
0°C to +70°C
-55°C to +125°C
-65°C to +150°C
+260°C
OPERATING ELECTRICAL CHARACTERISTICS
T
A
= 25
°
C V
S
=
±
5.0V unless otherwise specified
Parameter
Supply
Voltage
Input Offset
Voltage
Input Offset
Current
Input Bias
Current
Input Voltage
Range
Input
Resistance
Input Offset
Voltage Drift
Power Supply
Rejection Ratio
Common Mode
Rejection Ratio
Large Signal
Voltage Gain
Symbol
V
S
V
+
V
OS
I
OS
I
B
V
IR
R
IN
TCV
OS
PSRR
65
-5.3
10
12
1.0
1.0
Min
±3.25
6.5
4704A
Typ
Max
Min
4704B
Typ Max
Min
4704
Typ
Max
±6.0
12.0
5.0
6.0
1.0
1.0
-5.3
10
12
15
240
20
300
5.3
Unit
V
V
mV
mV
pA
pA
pA
pA
V
Ω
µV/°C
dB
R
S
≤
100KΩ
R
S
≤
100KΩ
0°C
≤
T
A
≤
+70°C
R
S
≤
100KΩ
0°C
≤
T
A
≤
+70°C
R
L
= 100KΩ
R
L
≥
1MΩ
R
L
= 10KΩ
R
L
= 10KΩ
0°C
≤
T
A
≤
+70°C
R
L
≥
1MΩ
0°C
≤
T
A
≤
+70°C
Test Conditions
Dual Supply
Single Supply
R
S
≤
100KΩ
0°C
≤
T
A
≤
+70°C
T
A
= 25°C
0°C
≤
T
A
≤
+70°C
T
A
= 25°C
0°C
≤
T
A
≤
+70°C
±6.0 ±3.25
12.0
6.5
1.0
1.5
15
240
20
300
5.3
-5.3
10
12
1.0
1.0
±6.0 ±3.25
12.0
6.5
2.0
3.0
15
240
20
300
5.3
5
80
65
5
80
60
5
80
CMRR
65
83
65
83
60
83
dB
A
V
15
28
100
15
28
100
10
28
100
V/mV
V/mV
V/mV
-4.90
-4.99
V
V
V
V
mA
13
mA
Output
Voltage
Range
V
O
low
V
O
high
V
O
low
V
O
high
I
SC
I
S
P
D
-4.96
4.90
4.95
-4.998
4.99 4.998
15
10
-4.90
-4.99
-4.96 -4.90
4.90 4.95
-4.998 -4.99
4.99 4.998
15
-4.96
4.90 4.95
-4.998
4.99 4.998
15
Output Short
Circuit Current
Supply
Current
Power
Dissipation
Input
Capacitance
Bandwidth
Slew Rate
Rise time
Overshoot
Factor
13
10
13
10
V
IN
= -5.0V
No Load
All amplifiers, No Load
V
S
=
±5.0V
130
130
130
mW
C
IN
1
1
1
pF
B
W
S
R
t
r
2.1
5.0
0.1
15
2.1
5.0
0.1
15
2.1
5.0
0.1
15
MHz
V/µs
µs
%
A
V
= +1 R
L
= 2.0KΩ
R
L
= 10KΩ
R
L
= 10KΩ
C
L
= 100pF
ALD4704A/ALD4704B
ALD4704
Advanced Linear Devices
2
OPERATING ELECTRICAL CHARACTERISTICS (cont'd)
T
A
= 25
°
C V
S
=
±
5.0V unless otherwise specified
4704A
Parameter
Maximum Load
Capacitance
Symbol
C
L
Min
Typ
400
4000
Max
Min
4704B
Typ
400
4000
Max
Min
4704
Typ
400
4000
Max
Unit
pF
pF
Test Conditions
Gain = 1
Gain = 5
Input Noise
Voltage
e
n
26
26
26
nV/√Hz
f =1KHz
Input Current
Noise
i
n
0.6
0.6
0.6
fA/√Hz
f =10Hz
Settling
Time
t
s
5.0
2.0
5.0
2.0
5.0
2.0
µs
µs
0.01%
0.1% A
V
= -1
R
L
= 5KΩ C
L
= 50pF
V
S
=
±
5.0V -55
°
C
≤
T
A
≤
+125
°
C unless otherwise specified
Parameter
Input Offset
Voltage
Input Offset
Current
Input Bias
Current
Power Supply
Rejection Ratio
Common Mode
Rejection Ratio
Large Signal
Voltage Gain
Output Voltage
Range
Symbol
V
OS
4704A DB
Min
Typ Max
2.0
4704B DB
Min Typ Max
4.0
Min
4704DB
Typ
Max
7.0
Unit
mV
Test Conditions
R
S
≤
100KΩ
I
OS
8.0
8.0
8.0
nA
I
B
10.0
10.0
10.0
nA
PSRR
60
75
60
75
60
75
dB
R
S
≤
100KΩ
CMRR
60
83
60
83
60
83
dB
R
S
≤
100KΩ
AV
10
25
10
25
10
25
V/mV
R
L
=10KΩ
V
O
low
V
O
high
4.8
-4.9
4.9
-4.8
4.8
-4.9
4.9
-4.8
4.8
-4.9
4.9
-4.8
V
V
R
L
=10KΩ
R
L
=10KΩ
ALD4704A/ALD4704B
ALD4704
Advanced Linear Devices
3
Design & Operating Notes:
1. The ALD4704 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. The ALD4704 is internally compensated for unity
gain stability using a novel scheme. This design 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 ALD4704 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 ALD4704 is much more
resistant to parasitic oscillations.
2. The ALD4704 has complementary p-channel and n-channel input
differential stages connected in parallel to accomplish rail to rail input
common mode voltage range. With the common mode input voltage
close to the power supplies, one of the two differential stages is
switched off internally. To maintain compatibility with other opera-
tional amplifiers, this switching point has been selected to be about
1.5V above the negative supply voltage. As offset voltage trimming on
the ALD4704 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 greater than 2.5 (5V operation), where the common mode
voltage does not make excursions below this switching point.
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. For
applications where source impedance is very high, it may be neces-
sary 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 the ALD4704 an effective analog signal buffer for medium to
high source impedance sensors, transducers, and other circuit net-
works.
5. The ALD4704 operational amplifier has been designed with static
discharge protection and to minimize latch up. However, care must be
exercised when handling the device to avoid strong static fields. 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. Alternatively, a 100KΩ or higher value resistor at the input
terminals will limit input currents to acceptable levels while causing
very small or negligible accuracy effects.
TYPICAL PERFORMANCE CHARACTERISTICS
COMMON MODE INPUT VOLTAGE RANGE
AS A FUNCTION OF SUPPLY VOLTAGE
±7
T
A
= 25°C
OPEN LOOP VOLTAGE GAIN AS A FUNCTION
OF SUPPLY VOLTAGE AND TEMPERATURE
1000
} -55°C
COMMON MODE INPUT
VOLTAGE RANGE (V)
OPEN LOOP VOLTAGE
GAIN (V/mV)
±6
±5
±4
±3
±2
±2
±3
±4
±5
±6
±7
SUPPLY VOLTAGE (V)
} +25°C
100
} +125°C
10
R
L
= 10KΩ
R
L
= 5KΩ
1
0
±2
±4
SUPPLY VOLTAGE (V)
±6
±8
INPUT BIAS CURRENT AS A FUNCTION
OF AMBIENT TEMPERATURE
10000
16
SUPPLY CURRENT AS A FUNCTION
OF SUPPLY VOLTAGE
14
12
10
8
6
4
2
T
A
= -55°C
-25°C
+25°C
+80°C
+125°C
INPUTS GROUNDED
OUTPUT UNLOADED
INPUT BIAS CURRENT (pA)
1000
100
10
1.0
0.1
-50
-25
0
25
50
75
100
125
SUPPLY CURRENT (mA)
V
S
=
±5.0V
0
0
±1
±2
±3
±4
±5
±6
±7
AMBIENT TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
ALD4704A/ALD4704B
ALD4704
Advanced Linear Devices
4
TYPICAL PERFORMANCE CHARACTERISTICS
OUTPUT VOLTAGE SWING AS A
FUNCTION OF SUPPLY VOLTAGE
120
±25°C ≤
T
A
≤
125°C
OPEN LOOP VOLTAGE
GAIN (dB)
RL = 10KΩ
R
L
= 10KΩ
OPEN LOOP VOLTAGE AS A
FUNCTION OF FREQUENCY
100
80
60
40
20
0
-20
V
S
=
±5.0V
T
A
= 25°C
0
45
90
135
180
1
10
100
1K
10K
100K
1M
10M
±7
OUTPUT VOLTAGE SWING (V)
±6
±5
±4
±3
±2
0
PHASE SHIFT IN DEGREES
R
L
= 2KΩ
±1
±2
±3
±4
±5
±6
±7
SUPPLY VOLTAGE (V)
FREQUENCY (Hz)
INPUT OFFSET VOLTAGE AS A FUNCTION
OF AMBIENT TEMPERATURE
REPRESENTATIVE UNITS
INPUT OFFSET VOLTAGE (mV)
V
S
=
±5.0V
INPUT OFFSET VOLTAGE AS A FUNCTION
OF COMMON MODE INPUT VOLTAGE
15
INPUT OFFSET VOLTAGE (mV)
+5
+4
+3
+2
+1
0
-1
-2
-3
-4
-5
-50
-25
0
+25
+50
10
5
0
-5
-10
-15
V
S
=
±5.0V
T
A
= 25°C
+75
+100 +125
-4
-2
0
+2
+4
+6
AMBIENT TEMPERATURE (°C)
COMMON MODE INPUT VOLTAGE (V)
OPEN LOOP VOLTAGE GAIN AS A
FUNCTION OF LOAD RESISTANCE
1000
150
VOLTAGE NOISE DENSITY AS A
FUNCTION OF FREQUENCY
VOLTAGE NOISE DENSITY
(nV/
√
Hz)
125
100
75
50
25
0
V
S
=
±5.0V
T
A
= 25°C
OPEN LOOP VOLTAGE
GAIN (V/mV)
100
V
S
=
±5.0V
T
A
= 25°C
10
1
1K
10K
100K
1000K
10
100
1K
10K
100K
1000K
LOAD RESISTANCE (Ω)
FREQUENCY (Hz)
LARGE - SIGNAL TRANSIENT
RESPONSE
5V/div
V
S
=
±5.0V
T
A
= 25°C
R
L
= 1KΩ
C
L
= 50pF
SMALL - SIGNAL TRANSIENT
RESPONSE
100mV/div
V
S
=
±
5.0V
T
A
= 25°C
R
L
= 1.0KΩ
C
L
= 50pF
5V/div
2µs/div
50mV/div
1µs/div
ALD4704A/ALD4704B
ALD4704
Advanced Linear Devices
5
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