Analog Devices AD549SH-883B, AD549SH, AD549LH, AD549KH, AD549JH Datasheet
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CONNECTION DIAGRAM
AD549
OFFSET NULL
OUTPUT
NC
V–
OFFSET
NULL
NONINVERTING
INPUT
6
7
1
3
4
5
2
8
V+
GUARD PIN, CONNECTED TO CASE
INVERTING
INPUT
1
4
5
VOS TRIM
–15V
10kΩ
NC = NO CONNECTION
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
a
Ultralow Input Bias Current
Operational Amplifier
AD549*
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 Fax: 617/326-8703
FEATURES
Ultralow Bias Current: 60 fA max (AD549L)
250 fA max (AD549J)
Input Bias Current Guaranteed Over Common-Mode
Voltage Range
Low Offset Voltage: 0.25 mV max (AD549K)
1.00 mV max (AD549J)
Low Offset Drift: 5 mV/8C max (AD549K)
20 mV/8C max (AD549J)
Low Power: 700 mA max Supply Current
Low Input Voltage Noise: 4 mV p-p 0.1 Hz to 10 Hz
MIL-STD-883B Parts Available
APPLICATIONS
Electrometer Amplifiers
Photodiode Preamp
pH Electrode Buffer
Vacuum lon Gage Measurement
PRODUCT DESCRIPTION
The AD549 is a monolithic electrometer operational amplifier
with very low input bias current. Input offset voltage and input
offset voltage drift are laser trimmed for precision performance.
The AD549’s ultralow input current is achieved with “Topgate”
JFET technology, a process development exclusive to Analog
Devices. This technology allows the fabrication of extremely low
input current JFETs compatible with a standard junctionisolated bipolar process. The 10
15
Ω common-mode impedance,
a result of the bootstrapped input stage, insures that the input
current is essentially independent of common-mode voltage.
The AD549 is suited for applications requiring very low input
current and low input offset voltage. It excels as a preamp for a
wide variety of current output transducers such as photodiodes,
photomultiplier tubes, or oxygen sensors. The AD549 can also
be used as a precision integrator or low droop sample and hold.
The AD549 is pin compatible with standard FET and electrometer op amps, allowing designers to upgrade the performance of
present systems at little additional cost.
The AD549 is available in a TO-99 hermetic package. The case
is connected to Pin 8 so that the metal case can be independently
connected to a point at the same potential as the input terminals, minimizing stray leakage to the case.
*Protected by Patent No. 4,639,683.
The AD549 is available in four performance grades. The J, K,
and L versions are rated over the commercial temperature range
0°C to +70°C. The S grade is specified over the military temperature range of –55°C to +125°C and is available processed to
MIL-STD-883B, Rev C. Extended reliability PLUS screening is
also available. Plus screening includes 168-hour burn-in, as
well as other environmental and physical tests derived from
MIL-STD-883B, Rev C.
PRODUCT HIGHLIGHTS
1. The AD549’s input currents are specified, 100% tested and
guaranteed after the device is warmed up. Input current is
guaranteed over the entire common-mode input voltage
range.
2. The AD549’s input offset voltage and drift are laser trimmed
to 0.25 mV and 5 µV/°C (AD549K), 1 mV and 20 µV/°C
(AD549J).
3. A maximum quiescent supply current of 700 µA minimizes
heating effects on input current and offset voltage.
4. AC specifications include 1 MHz unity gain bandwidth and
3 V/µs slew rate. Settling time for a 10 V input step is 5 µs to
0.01%.
5. The AD549 is an improved replacement for the AD515,
OPA104, and 3528.
AD549–SPECIFICATIONS
Model AD549J AD549K AD549L AD549S
Min Typ Max Min Typ Max Min Typ Max Min Typ Max Units
INPUT BIAS CURRENT
1
Either Input, VCM = 0 V 150 250 75 100 40 60 75 100 fA
Either Input, VCM = ± 10 V 150 250 75 100 40 60 75 100 fA
Either Input at T
MAX
,
VCM = 0 V 11 4.2 2.8 420 pA
Offset Current 50 30 20 30 fA
Offset Current at T
MAX
2.2 1.3 0.85 125 pA
INPUT OFFSET VOLTAGE
2
Initial Offset 0.5 1.0 0.15 0.25 0.3 0.5 0.3 0.5 mV
Offset at T
MAX
1.9 0.4 0.9 2.0 mV
vs. Temperature 10 20 2 5 5 10 10 15 µV/°C
vs. Supply 32 100 10 32 10 32 10 32 µV/V
vs. Supply, T
MIN
to T
MAX
32 100 10 32 10 32 32 50 µV/V
Long-Term Offset Stability 15 15 15 15 µV/Month
INPUT VOLTAGE NOISE
f = 0.1 Hz to 10 Hz 4 4 6 44µV p-p
f = 10 Hz 90 90 90 90 nV/√Hz
f = 100 Hz 60 60 60 60 nV/√Hz
f = 1 kHz 35 35 35 35 nV/√Hz
f = 10 kHz 35 35 35 35 nV/√Hz
INPUT CURRENT NOISE
f = 0.1 Hz to 10 Hz 0.7 0.5 0.36 0.5 fA rms
f = 1 kHz 0.22 0.16 0.11 0.16 fA/√Hz
INPUT IMPEDANCE
Differential
V
DIFF
= ±110
13
i110
13
i110
13
i110
13
i1 ΩipF
Common Mode
V
CM
= ± 10 1015i0.8 1015i0.8 1015i0.8 1015i0.8 ΩipF
OPEN-LOOP GAIN
VO @ ±10 V, RL = 10 k 300 1000 300 1000 300 1000 300 1000 V/mV
VO @ ±10 V, RL = 10 k,
T
MIN
to T
MAX
300 800 300 800 300 800 300 800 V/mV
VO = ±10 V, RL = 2 k 100 250 100 250 100 250 100 250 V/mV
VO = ±10 V, RL = 2 k,
T
MIN
to T
MAX
80 200 80 200 80 200 25 150 V/mV
INPUT VOLTAGE RANGE
Differential
3
±20 ±20 ±20 ±20 V
Common-Mode Voltage –10 +10 –10 +10 –10 +10 –10 +10 V
Common-Mode Rejection Ratio
V = +10 V, –10 V 80 90 90 100 90 100 90 100 dB
T
MIN
to T
MAX
76 80 80 90 80 90 80 90 dB
OUTPUT CHARACTERISTICS
Voltage @ RL = 10 k,
T
MIN
to T
MAX
–12 +12 –12 +12 –12 +12 –12 +12 V
Voltage @ RL = 2 k,
T
MIN
to T
MAX
–10 +10 –10 +10 –10 +10 –10 +10 V
Short Circuit Current 15 20 35 15 20 35 15 20 35 15 20 35 mA
T
MIN
to T
MAX
9996mA
Load Capacitance Stability
G = +1 4000 4000 4000 4000 pF
FREQUENCY RESPONSE
Unity Gain, Small Signal 0.7 1.0 0.7 1.0 0.7 1.0 0.7 1.0 MHz
Full Power Response 50 50 50 50 kHz
Slew Rate 2 3 2 3 2 3 2 3 V/µs
Settling Time, 0.1% 4.5 4.5 4.5 4.5 µs
0.01%5555µs
Overload Recovery,
50% Overdrive, G = –1 2222µs
(@ +258C and VS = +15 V dc, unless otherwise noted)
REV. A
–2–
Model AD549J AD549K AD549L AD549S
Min Typ Max Min Typ Max Min Typ Max Min Typ Max Units
POWER SUPPLY
Rated Performance ±15 ±15 ±15 ±15 V
Operating 65 618 65 618 65 618 65 618 V
Quiescent Current 0.60 0.70 0.60 0.70 0.60 0.70 0.60 0.70 mA
TEMPERATURE RANGE
Operating, Rated Performance 0 +70 0 +70 0 +70 –55 +125 °C
Storage –65 +150 –65 +150 –65 +150 –65 +150 °C
PACKAGE OPTION
TO-99 (H-08A) AD549JH AD549KH AD549LH AD549SH, AD549SH/883B
Chips AD549JChips
NOTES
1
Bias current specifications are guaranteed after 5 minutes of operation at TA = +25°C. Bias current increases by a factor of 2.3 for every 10°C rise in temperature.
2
Input offset voltage specifications are guaranteed after 5 minutes of operation at TA = +25°C.
3
Defined as max continuous voltage between the inputs such that neither input exceeds ±10 V from ground.
Specifications subject to change without notice.
All min and max specifications are guaranteed. Specifications in boldface are tested on all production units at final electrical test. Results from those tests are used to
calculate outgoing quality levels.
METALIZATION PHOTOGRAPH
Dimensions shown in inches and (mm).
Contact factory for latest dimensions.
ABSOLUTE MAXIMUM RATINGS
1
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±18 V
Internal Power Dissipation . . . . . . . . . . . . . . . . . . . . . .500 mW
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±18 V
2
Output Short Circuit Duration . . . . . . . . . . . . . . . . . Indefinite
Differential Input Voltage . . . . . . . . . . . . . . . . . . +V
S
and –V
S
Storage Temperature Range (H) . . . . . . . . . .–65°C to +125°C
Operating Temperature Range
AD549J (K, L) . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C
AD549S . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C
Lead Temperature Range (Soldering 60 sec) . . . . . . . . +300°C
NOTES
1
Stresses above those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. This is a stress rating only and functional
operation of the device at these or any other conditions above those indicated in the
operational section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
2
For supply voltages less than ±18 V, the absolute maximum input voltage is equal
to the supply voltage.
AD549
REV. A
–3–
WARNING!
ESD SENSITIVE DEVICE
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD549 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
AD549–Typical Characteristics
SUPPLY VOLTAGE ± V
INPUT VOLTAGE ± V
20
15
10
5
0
0 5 10 15 20
+V
IN
–V
IN
Figure 1. Input Voltage Range
vs. Supply Voltage
SUPPLY VOLTAGE ± V
800
700
600
500
400
AMPLIFIER QUIESCENT CURRENT – µA
0 5 10 15 20
Figure 4. Quiescent Current
vs. Supply Voltage
TEMPERATURE – °C
3000
OPEN-LOOP GAIN – V/mV
–55 –25 5 35 65 95 125
1000
300
100
Figure 7. Open-Loop Gain vs.
Temperature
SUPPLY VOLTAGE ± V
20
15
10
5
0
OUTPUT VOLTAGE SWING ± V
0 5 10 15 20
+V
OUT
–V
OUT
+25°C
R
L
= 10k
Figure 2. Output Voltage
Swing vs. Supply Voltage
INPUT COMMON-MODE VOLTAGE – V
120
100
90
80
70
COMMON-MODE REJECTION RATIO – dB
–15 –10 0 +10 +15
110
Figure 5. CMRR vs. Input
Common-Mode Voltage
WARM-UP TIME – Minutes
30
∆ |V
OS
| – µV
0 1 2 3 4 5 6 7
25
20
15
10
5
0
Figure 8. Change in Offset
Voltage vs. Warm-Up Time
LOAD RESISTANCE – Ω
30
25
20
10
0
10 100 1k 10k 100k
5
15
OUTPUT VOLTAGE SWING – Volts p-p
VS = ±15 VOLTS
Figure 3. Output Voltage
Swing vs. Load Resistance
SUPPLY VOLTAGE ± V
3000
OPEN-LOOP GAIN – V/mV
0 5 10 15 20
1000
300
100
Figure 6. Open-Loop Gain vs.
Supply Voltage
COMMON-MODE VOLTAGE ± V
50
INPUT CURRENT – fA
–10 –5 0 5 10
40
35
20
30
25
45
Figure 9. Input Bias Current
vs. Common-Mode Voltage
REV. A
–4–
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