RAIL-TO-RAIL CMOS OPERATIONAL AMPLIFIER
ADVANCED
LINEAR
DEVICES, INC.
ALD1704A/ALD1704B
ALD1704/ALD1704G
GENERAL DESCRIPTION
The ALD1704 is a CMOS monolithic operational amplifier with MOSFET
input that has rail-to-rail input and output voltage ranges. The input voltage
range and output voltage range are very close to the positive and negative
power supply voltages. Typically 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.
This device is designed as an alternative to the popular JFET 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 of 30mW. Since the ALD1704
is designed and manufactured with Advanced Linear Devices' standard
enhanced ACMOS silicon gate CMOS process, it also offers low unit cost
and exceptional reliability.
The rail-to-rail input and output feature of the ALD1704 allows a lower
operating supply voltage for a given signal voltage range and allows
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 1.5K Ω resistive loads at unity gain and up to
4000 pF at a gain of 5. Short circuit protection to either ground or the power
supply rails is at approximately 15mA clamp current. Due to complemen-
tary output stage design, 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.
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 ultra high 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.
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
FEATURES
• Rail-to-rail input and output voltage ranges
• 5.0V/µs slew rate
• Output settles to 2mV of supply rails
• High capacitive load capability -- up to 4000pF
• Symmetrical push-pull output drives
• No frequency compensation required --
unity gain stable
• Extremely low input bias currents -- 1.0pA
typical (20pAMax)
• Ideal for high source impedance applications
• High voltage gain -- typically 150V/mV
• Output short circuit protected
• Unity gain bandwidth of 2.1MHz
ORDERING INFORMATION
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 Package (SOIC) Package
ALD1704A DA ALD1704A SA ALD1704A PA
ALD1704B DA ALD1704B SA ALD1704B PA
ALD1704 DA ALD1704 SA ALD1704 PA
ALD1704G DA ALD1704G SA ALD1704G PA
* Contact factory for industrial temperature range
PIN CONFIGURATION
* N/C Pin is internally connected. Do not connect externally.
1
2
3
4
8
7
6
5
TOP VIEW
DA, PA, SA PACKAGE
N/C
-IN
+IN
N/C
OUT
N/CV-
V+
© 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
ALD1704A/ALD1704B Advanced Linear Devices 2
ALD1704/ALD1704G
Supply VS±3.25 ±6.0 ±3.25 ±6.0 ±3.25 ±6.0 ±3.25 ±6.0 V Dual Supply
Voltage V+6.5 12.0 6.5 12.0 6.5 12.0 6.5 12.0 V Single Supply
Input Offset VOS 0.9 2.0 4.5 10.0 mV RS ≤ 100KΩ
Voltage 1.7 2.8 5.3 11.0 mV 0°C ≤ TA ≤ +70°C
Input Offset IOS 1.0 15 1.0 15 1.0 15 1.0 25 pA TA = 25°C
Current 240 240 240 240 pA 0°C ≤ TA ≤ +70°C
Input Bias IB1.0 20 1.0 20 1.0 20 1.0 30 pA TA = 25°C
Current 300 300 300 300 pA 0°C ≤ TA ≤ +70°C
Input Voltage VIR -5.3 +5.3 -5.3 +5.3 -5.3 +5.3 ±5.0 V
Range
Input RIN 1012 1012 1012 1012 Ω
Resistance
Input Offset TCVOS 5557µV/°CR
S
≤ 100KΩ
Voltage Drift
Power Supply PSRR 70 80 65 80 65 80 60 80 dB RS ≤ 100KΩ
Rejection Ratio 0°C ≤ TA ≤ +70°C
Common Mode CMRR 70 83 65 83 65 83 60 83 dB RS ≤ 100KΩ
Rejection Ratio 0°C ≤ TA ≤ +70°C
Large Signal AV50 150 50 150 50 150 32 150 V/ mV RL = 10KΩ
Voltage Gain 150 150 150 150 V/ mV No Load
40 40 40 20 V/ mV 0°C ≤ TA ≤ +70°C
Output VO low -4.96 -4.90 -4.96 -4.90 -4.96 -4.90 -4.96 -4.90 V RL = 10KΩ
Voltage VO high 4.90 4.95 4.90 4.95 4.90 4.95 4.90 4.95 0°C ≤ TA ≤ +70°C
Range VO low -4.998 -4.99 -4.998 -4.99 -4.998 -4.99 -4.998 -4.99 V RL =1MΩ
VO high 4.99 4.998 4.99 4.998 4.99 4.998 4.99 4.998 0°C ≤ TA ≤ +70°C
Output Short ISC 15 15 15 15 mA
Circuit Current
Supply Current IS3.0 4.5 3.0 4.5 3.0 4.5 3.0 5.0 mA VIN = 0V
No Load
Power PD30 45 30 45 30 45 30 50 mW VS = ±5.0
Dissipation No Load
Input CIN 1111pF
Capacitance
Bandwidth BW2.1 2.1 2.1 2.1 MHz
Slew Rate SR 5.0 5.0 5.0 5.0 V/µsA
V
= +1
RL = 2.0KΩ
Rise time t r 0.1 0.1 0.1 0.1 µsR
L
= 2.0KΩ
Overshoot 15 15 15 15 % RL = 2.0KΩ
Factor CL = 100pF
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
OPERATING ELECTRICAL CHARACTERISTICS
TA = 25°C VS = ±5.0V unless otherwise specified
1704A 1704B 1704 1704G Test
Parameter Symbol Min Typ Max Min Typ Max Min Typ Max Min Typ Max Unit Conditions
ALD1704A/ALD1704B Advanced Linear Devices 3
ALD1704/ALD1704G
Maximum Load CL400 400 400 400 pF Gain = 1
Capacitance 4000 4000 4000 4000 pF Gain = 5
Input Noise
Voltage en26 26 26 26 nV/√Hzf = 1KHZ
Input Current
Noise in0.6 0.6 0.6 0.6 fA/√HZf = 10HZ
Settling ts5.0 5.0 5.0 5.0 µs 0.01%
Time 2.0 2.0 2.0 2.0 µs 0.1% AV = -1
RL = 5KΩ
CL = 50pF
OPERATING ELECTRICAL CHARACTERISTICS (cont'd)
TA = 25°C VS = ±5.0V unless otherwise specified
1704A 1704B 1704 1704G
Parameter Symbol Min Typ Max Min Typ Max Min Typ Max Min Typ Max Unit Test Conditions
Input Offset Voltage VOS 2.0 4.0 7.0 mV RS ≤ 100KΩ
Input Offset Current IOS 8.0 8.0 8.0 nA
Input Bias Current IB10.0 10.0 10.0 nA
Power Supply PSRR 60 75 60 75 60 75 dB RS ≤ 100KΩ
Rejection Ratio
Common Mode CMRR 60 83 60 83 60 83 dB RS ≤ 100KΩ
Rejection Ratio
Large Signal AV30 125 30 125 30 125 V/mV RL = 10KΩ
Voltage Gain
Output Voltage VO low -4.9 -4.8 -4.9 -4.8 -4.9 -4.8 V RL = 10KΩ
Range VO high 4.8 4.9 4.8 4.9 4.8 4.9 V RL = 10KΩ
VS = ±5.0V -55°C ≤ TA ≤ +125°C unless otherwise specified
1704A DA 1704B DA 1704DA
Parameter Symbol Min Typ Max Min Typ Max Min Typ Max Unit Test Conditions
ALD1704A/ALD1704B Advanced Linear Devices 4
ALD1704/ALD1704G
TYPICAL PERFORMANCE CHARACTERISTICS
Design & Operating Notes:
1. The ALD1704 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 ALD1704 is internally compensated for unity
gain stability using a novel scheme that 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 ALD1704 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 ALD1704 has shown itself
to be more resistant to parasitic oscillations.
2. The ALD1704 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 compat-
ibility with other operational amplifiers, this switching point has been
selected to be about 1.5V above the negative supply voltage. Since
offset voltage trimming on the ALD1704 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 (10V
operation), where the common mode voltage does not make excur-
sions 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 applica-
tions 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 symmetrical class AB complementary
output drivers, capable of driving a low resistance load with up to 10mA
source current and 10mA sink current. 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 ALD1704 an effective analog signal buffer for medium to high source
impedance sensors, transducers, and other circuit networks.
5. The ALD1704 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.
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
V
S
= ±5.0V
10000
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
R
L
= 10KΩ
R
L
= 5KΩ
} -55°C
} +25°C
} +125°C
±8
SUPPLY CURRENT AS A FUNCTION
OF SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
5
4
3
2
1
0
SUPPLY CURRENT (mA)
0±1±2±3±4±5±6
+125°C
+80°C
+25°C
TA = -55°C
-25°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±2 ±3 ±4 ±5 ±6 ±7
T
A
= 25°C
ALD1704A/ALD1704B Advanced Linear Devices 5
ALD1704/ALD1704G
TYPICAL PERFORMANCE CHARACTERISTICS
LARGE - SIGNAL TRANSIENT
RESPONSE
V
S
= ±5.0V
T
A
= 25°C
R
L
= 1KΩ
C
L
= 50pF
5V/div
5V/div 2µs/div
SMALL - SIGNAL TRANSIENT
RESPONSE
V
S
= ± 5.0V
T
A
= 25°C
R
L
= 1.0KΩ
C
L
= 50pF
100mV/div
50mV/div 1µs/div
OPEN LOOP VOLTAGE GAIN AS A FUNCTION
OF LOAD RESISTANCE
LOAD RESISTANCE (Ω)
1K 10K 1000K100K
1000
100
10
1
OPEN LOOP VOLTAGE
GAIN (V/mV)
V
S
= ±5.0V
T
A
= 25°C
OPEN LOOP VOLTAGE 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
= ±5.0V
T
A
= 25°C
90
0
45
180
135
PHASE SHIFT IN DEGREES
INPUT OFFSET VOLTAGE AS A FUNCTION
OF COMMON MODE INPUT VOLTAGE
COMMON MODE INPUT VOLTAGE (V)
-4 -2 0 +2 +4 +6
15
10
5
0
-5
-10
-15
INPUT OFFSET VOLTAGE (mV)
V
S
= ±5.0V
T
A
= 25°C
RL = 10KΩ
OUTPUT VOLTAGE SWING AS A
FUNCTION OF SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
OUTPUT VOLTAGE SWING (V)
±3
0±1±2±3±4±5±6±7
R
L
= 2KΩ
±6
±5
±4
±2
±7
±25°C ≤ T
A
≤ 125°C
R
L
= 10KΩ
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
= ±5.0V
VOLTAGE NOISE DENSITY AS A
FUNCTION OF FREQUENCY
FREQUENCY (Hz)
10 100 1K 10K 100K
150
125
100
75
50
25
0
1000K
VOLTAGE NOISE DENSITY
(nV/ √ Hz)
V
S
= ±5.0V
T
A
= 25°C
ALD1704A/ALD1704B Advanced Linear Devices 6
ALD1704/ALD1704G
Cutoff frequency = π R1C1 = 3.2kHz
Gain = 10 Frequency roll-off 20dB/decade
1
TYPICAL APPLICATIONS
RAIL-TO-RAIL VOLTAGE FOLLOWER/BUFFER
-
+
V
IN
+10V
C
L
R
L
0.1µF
Z
IN
= 10
12
Ω
~
400pF ≥ 1.5KΩ
V
OUT
0 ≤ V
IN
≤ 10V
RAIL-TO-RAIL VOLTAGE COMPARATOR
-
+
50K
0.1µF
10M
V
IN
+12V
+12V
V
OUT
LOW OFFSET SUMMING AMPLIFIER
INPUT 1
INPUT 2
-
+
+5V 0.1µF
0.1µF
-5V
GAIN = 5 C
L
= 4000pF
* Circuit Drives Large Load
Capacitance ≤ 4000pF
10K
10K
50K
V
OUT
PHOTO DETECTOR CURRENT
TO VOLTAGE CONVERTER
WIEN BRIDGE OSCILLATOR (RAIL-TO -RAIL)
SINE WAVE GENERATOR
10K
-
+
10K
10K
+5V
-5V
.01µF
1
2πRC
f = 1.6K Hz
C = .01µFR = 10K
~=
VOUT
~
LOW PASS FILTER (RFI FILTER)
R1 = 10K C1 = 100nF
R2 = 10K C2 = 500pF
+
R
F
100K
5K5K
0.02µF
R
1
R
1
C
1
+9V
V
IN
V
OUT
-
Low Frequency
Breakpoint ƒL = 2π R1 C1 = 160Hz
High Frequency
Cutoff ƒH = 2π R2C2 = 32KHz
1
1
+
-+5V
-5V
RF = 5M
I
PHOTODIODE VOUT = I X RF
RL ≥ 1.5K
PRECISION CHARGE INTEGRATOR
+
1000pF
1MΩ+5V
-5V
V
IN
V
OUT
-
BANDPASS NETWORK
+
+5V
-5V
C
1
R
1
C
2
R
2
V
IN
V
OUT
-
