Analog Devices AD797BR-REEL7, AD797BR-REEL, AD797BR, AD797BN, AD797AR-REEL7 Datasheet

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2

3

4

8

7
6

5

AD797

DECOMPENSATION &
DISTORTION
NEUTRALIZATION

OUTPUT

OFFSET NULL

–IN
+IN

+V

S

–V

S

OFFSET NULL

TOP VIEW

Ultralow Distortion,

a

FEATURES
Low Noise

0.9 nV/√Hz typ (1.2 nV/√Hz max) Input Voltage

Noise at 1 kHz

50 nV p-p Input Voltage Noise, 0.1 Hz to 10 Hz

Low Distortion

–120 dB Total Harmonic Distortion at 20 kHz

Excellent AC Characteristics

800 ns Settling Time to 16 Bits (10 V Step)
110 MHz Gain Bandwidth (G = 1000)
8 MHz Bandwidth (G = 10)
280 kHz Full Power Bandwidth at 20 V p-p
20 V/ms Slew Rate

Excellent DC Precision

80 mV max Input Offset Voltage

1.0 mV/8C V
Specified for 65 V and 615 V Power Supplies
High Output Drive Current of 50 mA

APPLICATIONS
Professional Audio Preamplifiers
IR, CCD, and Sonar Imaging Systems
Spectrum Analyzers
Ultrasound Preamplifiers
Seismic Detectors
SD ADC/DAC Buffers

PRODUCT DESCRIPTION

The AD797 is a very low noise, low distortion operational
amplifier ideal for use as a preamplifier. The low noise of

0.9 nV/√

Hz and low total harmonic distortion of –120 dB at

audio bandwidths give the AD797 the wide dynamic range

OS

Drift

Ultralow Noise Op Amp

AD797*

CONNECTION DIAGRAM

8-Pin Plastic Mini-DIP (N),

Cerdip (Q) and SOIC (R) Packages

necessary for preamps in microphones and mixing consoles.
Furthermore, the AD797’s excellent slew rate of 20 V/µs and
110 MHz gain bandwidth make it highly suitable for low fre­quency ultrasound applications.

The AD797 is also useful in IR and Sonar Imaging applications
where the widest dynamic range is necessary. The low distor­tion and 16-bit settling time of the AD797 make it ideal for
buffering the inputs to Σ∆ ADCs or the outputs of high resolu­tion DACs especially when they are used in critical applications
such as seismic detection and spectrum analyzers. Key features
such as a 50 mA output current drive and the specified power
supply voltage range of ±5 to ±15 volts make the AD797 an
excellent general purpose amplifier.

5

Hz

4

3

2

1

INPUT VOLTAGE NOISE – nV/

0

100

10

FREQUENCY – Hz

1M100k10k1k

AD797 Voltage Noise Spectral Density

*Patent pending.

REV. C

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.

10M

–90

–100

–110

THD – dB

–120

–130

MEASUREMENT
LIMIT

300100

FREQUENCY – Hz

100k30k10k3k1k

0.001

0.0003

0.0001

300k

THD vs. Frequency

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] Fax: [phone]

THD – %

AD797–SPECIFICATIONS

(@ TA = +258C and VS = 615 V dc, unless otherwise noted)

1

AD797B

Model Conditions V

AD797A/S

S

Min Typ Max Min Typ Max Units

INPUT OFFSET VOLTAGE ±5 V, ±15 V 25 80 10 40 µV

T

MIN

to T

MAX

50 125/180 30 60 µV

Offset Voltage Drift ±5 V, ±15 V 0.2 1.0 0.2 0.6 µV/°C

INPUT BIAS CURRENT ±5 V, ±15 V 0.25 1.5 0.25 0.9 µA

T

MIN

to T

MAX

0.5 3.0 0.25 2.0 µA

INPUT OFFSET CURRENT ±5 V, ±15 V 100 400 80 200 nA

T

OPEN-LOOP GAIN V

to T

MIN

MAX

= ±10 V ±15 V

OUT

R

= 2 kΩ 120 220 V/µV

LOAD

T

to T

MIN

R
T
@ 20 kHz

MAX

= 600 Ω 115 215 V/µV

LOAD

to T

MIN

MAX
2

16 210 V/µV

15 27 V/µV
14000 20000 14000 20000 V/V

120 600/700 120 300 nA

DYNAMIC PERFORMANCE

Gain Bandwidth Product G = 1000 ±15 V 110 110 MHz

G = 1000
–3 dB Bandwidth G = 10 ±15 V 8 8 MHz
Full Power Bandwidth

3

VO = 20 V p-p,

R
Slew Rate R

2

= 1 kΩ±15 V 280 280 kHz

LOAD

= 1 kΩ±15 V 12.5 20 12.5 20 V/µs

LOAD

±15 V 450 450 MHz

Settling Time to 0.0015% 10 V Step ±15 V 800 1200 800 1200 ns

COMMON-MODE REJECTION V

POWER SUPPLY REJECTION V

= CMVR ±5 V, ±15 V 114 130 120 130 dB

CM

T

to T

MIN

MAX

= ±5 V to ±18 V 114 130 120 130 dB

S

T

to T

MIN

MAX

110 120 114 120 dB

110 120 114 120 dB

INPUT VOLTAGE NOISE f = 0. 1 Hz to 10 Hz ±15 V 50 50 nV p-p

f = 10 Hz ±15 V 1.7 1.7 2.5 nV/√

f = 1 kHz ±15 V 0.9 1.2 0.9 1.2 nV/√

Hz
Hz

f = 10 Hz–1 MHz ±15 V 1.0 1.3 1.0 1.2 µV rms

INPUT CURRENT NOISE f = 1 kHz ±15 V 2.0 2.0 pA/√Hz
INPUT COMMON-MODE ±15 V ±11 ±12 ±11 ±12 V

VOLTAGE RANGE ±5 V ±2.5 ±3 ±2.5 ±3V

OUTPUT VOLTAGE SWING R

Short-Circuit Current ±5 V, ±15 V 80 80 mA
Output Current

4

TOTAL HARMONIC DISTORTION R

= 2 kΩ±15 V ±12 ±13 ±12 ±13 V

LOAD

R

= 600 Ω±15 V ±11 ±13 ±11 ±13 V

LOAD

R

= 600 Ω±5 V ±2.5 ±3 ±2.5 ±3V

LOAD

±5 V, ±15 V 30 50 30 50 mA

= 1 kΩ, CN = 50 pF ±15 V –98 –90 –98 –90 dB

LOAD

f = 250 kHz, 3 V rms

R

= 1 kΩ±15 V –120 –110 –120 –110 dB

LOAD

f = 20 kHz, 3 V rms

INPUT CHARACTERISTICS

Input Resistance (Differential) 7.5 7.5 kΩ
Input Resistance (Common Mode) 100 100 MΩ
Input Capacitance (Differential)

5

20 20 pF

Input Capacitance (Common Mode) 5 5 pF

OUTPUT RESISTANCE AV = +1, f = 1 kHz 3 3 mΩ
POWER SUPPLY

Operating Range ±5 ±18 ±5 ±18 V
Quiescent Current ±5 V, ±15 V 8.2 10.5 8.2 10.5 mA

NOTES

1

See standard military drawing for 883B specifications.

2

Specified using external decompensation capacitor, see Applications section.

3

Full Power Bandwidth = Slew Rate/2 π V

4

Output Current for |VS – V

5

Differential input capacitance consists of 1.5 pF package capacitance and 18.5 pF from the input differential pair.

Specifications subject to change without notice.

| >4 V, AOL > 200 kΩ.

OUT

PEAK

.

–2–

REV. C

AD797

ABSOLUTE MAXIMUM RATINGS

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±18 V

Internal Power Dissipation @ +25°C

Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .±V

1

2

S

Differential Input Voltage3 . . . . . . . . . . . . . . . . . . . . . . ±0.7 V

Output Short Circuit Duration . . . . . . .Indefinite Within max

Internal Power Dissipation

Storage Temperature Range (Cerdip) . . . . . . –65°C to +150°C

Storage Temperature Range (N, R Suffix) . . –65 °C to +125°C
Operating Temperature Range

AD797A/B . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C

AD797S . . . . . . . . . . . . . . . . . . . . . . . . . . –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

Internal Power Dissipation:
8-Pin SOIC = 0.9 Watts (TA–25°C)/θ
8-Pin Plastic DIP and Cerdip = 1.3 Watts – (TA–25°C)/θ
Thermal Characteristics
8-Pin Plastic DIP Package: θJA = 95°C/W
8-Pin Cerdip Package: θJA = 110°C/W
8-Pin Small Outline Package: θJA = 155°C/W

JA

JA

3

The AD797’s inputs are protected by back-to-back diodes. To achieve low noise,
internal current limiting resistors are not incorporated into the design of this
amplifier. If the differential input voltage exceeds ±0.7 V, the input current should
be limited to less than 25 mA by series protection resistors. Note, however, that this
will degrade the low noise performance of the device.

ESD SUSCEPTIBILITY

ESD (electrostatic discharge) sensitive device. Electrostatic
charges as high as 4000 volts, which readily accumulate on the
human body and on test equipment, can discharge without
detection. Although the AD797 features proprietary ESD pro­tection circuitry, permanent damage may still occur on these
devices if they are subjected to high energy electrostatic dis­charges. Therefore, proper ESD precautions are recommended
to avoid any performance degradation or loss of functionality.

ORDERING GUIDE

Model Range Description Option

AD797AN –40°C to +85°C 8-Pin Plastic DIP N-8
AD797BN –40°C to +85°C 8-Pin Plastic DIP N-8
AD797BR –40°C to +85°C 8-Pin Plastic SOIC SO-8
AD797BR-REEL –40°C to +85°C 8-Pin Plastic SOIC SO-8
AD797BR-REEL7 –40°C to +85°C 8-Pin Plastic SOIC SO-8
AD797AR –40°C to +85°C 8-Pin Plastic SOIC SO-8
AD797AR-REEL –40°C to +85°C 8-Pin Plastic SOIC SO-8
AD797AR-REEL7 –40°C to +85°C 8-Pin Plastic SOIC SO-8
5962-9313301MPA –55°C to +125°C 8-Pin Cerdip Q-8

Temperature Package Package

METALIZATION PHOTO

Contact factory for latest dimensions.

Dimensions shown in inches and (mm).

REV. C

NOTE
The AD797 has double layer metal. Only one layer is shown here for clarity.

–3–

AD797–Typical Characteristics

HORIZONTAL SCALE – 5 sec/DIV

VERTICAL SCALE – 0.01µV/DIV

–60 140–40 100 120806040200–20

–2.0

–1.5

–1.0

–0.5

0.0

INPUT BIAS CURRENT – µA

TEMPERATURE – °C

140

140

100

60

–40

80

–60

120

120100

80

6040200–20

40

TEMPERATURE – °C

SHORT CIRCUIT CURRENT – mA

SOURCE CURRENT

SINK CURRENT

20

15

10

5

INPUT COMMON-MODE RANGE – ±Volts

0

0

5

SUPPLY VOLTAGE – ±Volts

10

15

20

Figure 1. Common-Mode Voltage Range vs. Supply

20

15

10

–V

OUT

5

OUTPUT VOLTAGE SWING – ±Volts

0

0

5

SUPPLY VOLTAGE – ±Volts

+V

OUT

10

15

20

Figure 2. Output Voltage Swing vs. Supply

30

V = ±15V

S

Figure 4. 0.1 Hz to 10 Hz Noise

Figure 5. Input Bias Current vs. Temperature

20

10

OUTPUT VOLTAGE SWING – Volts p-p

0

10 100 10k1k

Figure 3. Output Voltage Swing vs. Load Resistance

LOAD RESISTANCE –

V = ±5V

S

Ω

Figure 6. Short Circuit Current vs. Temperature

–4–

REV. C

AD797

0

±5V SUPPLIES

±15V SUPPLIES

R

L

= 600Ω

11

10

9

8

7

QUIESCENT SUPPLY CURRENT – mA

6

+125°C

+25°C

–55°C

10

SUPPLY VOLTAGE – ±Volts

205015

Figure 7. Quiescent Supply Current vs. Supply Voltage

12

FREQ = 1kHz

= 600Ω

R

L

G = +10

9

6

3

OUTPUT VOLTAGE – Volts rms

140

120

100

80

60

POWER SUPPLY REJECTION – dB

40

20

10

1

PSR

–SUPPLY

FREQUENCY – Hz

PSR
+SUPPLY

CMR

150

125

100

75

50

100k10k1k100

1M

Figure 10. Power Supply and Common-Mode Rejection
vs. Frequency

–60

RL = 600

Ω

G = +10
FREQ = 10kHz
NOISE BW = 100kHz

–80

V

= ±5V

S

THD + NOISE – dB

–100

V

= ±15V

S

COMMON MODE REJECTION – dB

0

0

±5

SUPPLY VOLTAGE – Volts

±10

±15

Figure 8. Output Voltage vs. Supply for 0.01% Distortion

1.0

0.8

0.0015%

0.6

0.01%

0.4

SETTLING TIME – µs

0.2

0.0
0

Figure 9. Settling Time vs. Step Size (±)

2

STEP SIZE – Volts

864

±20

–120

0.01 0.1 101.0
OUTPUT LEVEL – Volts

Figure 11. Total Harmonic Distortion (THD) + Noise vs.
Output Level

10

Figure 12. Large Signal Frequency Response

REV. C

–5–