OP297GP现货热卖使用介绍供应商报价哪里找芯片批发报价-中国IC网-芯三七

8/21/97 4:00 PM

Dual Low Bias Current

Precision Operational Amplifier

a

OP297

FEATURES

PIN CONNECTIONS

Precision Performance in Standard SO-8 Pinout

Low Offset Voltage: 50 ␮V max

Low Offset Voltage Drift: 0.6 ␮V/؇C max

Very Low Bias Current:

Plastic Epoxy-DIP (P Suffix)

8-Pin Cerdip (Z Suffix)

8-Pin Narrow Body SOIC (S Suffix)

␣ ␣ +25؇C (100 pA max)

␣␣␣55؇C to +125؇C (450 pA max)

Very High Open-Loop Gain (2000 V/mV min)

Low Supply Current (Per Amplifier): 625 ␮A max

Operates From 62 V to 620 V Supplies

High Common-Mode Rejection: 120 dB min

Pin Compatible to LT1013, AD706, AD708, OP221,

␣ ␣ LM158, and MC1458/1558 with Improved Performance

OUT A 1

8 V+

B

A

–

–IN A

+IN A

V–

2

3

4

7 OUT B

6 –IN B

–

5

+IN B

APPLICATIONS

Strain Gauge and Bridge Amplifiers

High Stability Thermocouple Amplifiers

Instrumentation Amplifiers

Photo-Current Monitors

High-Gain Linearity Amplifiers

Long-Term Integrators/Filters

Sample-and-Hold Amplifiers

Peak Detectors

Errors due to common-mode signals are eliminated by the

OP297’s common-mode rejection of over 120 dB. The

OP297’s power supply rejection of over 120 dB minimizes

offset voltage changes experienced in battery powered systems.

Supply current of the OP297 is under 625 µA per amplifier and

it can operate with supply voltages as low as ±2 V.

The OP297 utilizes a super-beta input stage with bias current

cancellation to maintain picoamp bias currents at all tempera-

tures. This is in contrast to FET input op amps whose bias

currents start in the picoamp range at 25°C, but double for

every 10°C rise in temperature, to reach the nanoamp range

above 85°C. Input bias current of the OP 297 is under 100 pA

at 25°C and is under 450 pA over the military temperature

range.

Logarithmic Amplifiers

Battery-Powered Systems

GENERAL DESCRIPTION

The OP297 is the first dual op amp to pack precision perfor-

mance into the space-saving, industry standard 8-pin SO pack-

age. Its combination of precision with low power and extremely

low input bias current makes the dual OP297 useful in a wide

variety of applications.

Combining precision, low power and low bias current, the

OP297 is ideal for a number of applications including instru-

mentation amplifiers, log amplifiers, photodiode preamplifiers

and long-term integrators. For a single device, see the OP97;

for a quad, see the OP497.

Precision performance of the OP297 includes very low offset,

under 50 µV, and low drift, below 0.6 µV/°C. Open-loop gain

exceeds 2000 V/mV insuring high linearity in every application.

400

60

I

–

B

1200 UNITS

V

= ±15V

T

V

= +25°C

= ±15V

S

A

= 0V

CM

S

40

20

= 0V

CM

300

200

100

0

I

+

B

0

I

OS

20

–40

–60

–100 –80 –60 –40 –20

0

20 40 60 80 100

–75 –50 –25

0

25 50 75 100 125

INPUT OFFSET VOLTAGE (µV)

TEMPERATURE (°C)

Figure 1. Low Bias Current Over Temperature

REV. D

Figure 2. Very Low Offset

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.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 617/329-4700

Fax: 617/326-8703

World Wide Web Site: http://www.analog.com

8/21/97 4:00 PM

OP297–SPECIFICATIONS

(@ V_S= ؎15 V, T_A= +25؇C, unless otherwise noted.)

ELECTRICAL CHARACTERISTICS

OP297A/E

OP297F

OP297G

Parameter

Symbol Conditions

Min Typ Max Min Typ Max Min Typ Max

Units

Input Offset Voltage

Long-Term Input

Voltage Stability

Input Offset Current

Input Bias Current

Input Noise Voltage

Input Noise

Voltage Density

Input Noise Current Density

Input Resistance

V_OS

25

50

100

80

200

µV

0.1

20

0.5

20

17

20

0.1

35

0.5

20

17

20

0.1

50

0.5

20

17

20

µV/mo

pA

µV p-p

nV/√Hz

fA√Hz

I_OS

I_B

e_np-p

e_n

i_n

V_CM= 0 V

0.1 Hz to 10 Hz

f_O= 10 Hz

f_O= 1000 Hz

f_O= 10 Hz

100

±100

150

±150

200

±200

Differential Mode

Input Resistance

Common-Mode

R_IN

30

MΩ

GΩ

R_INCM

500

Large-Signal

V_O= ±10 V

Voltage Gain

A_VO

IVR

CMR

PSR

V_O

R_L= 2 kΩ

(Note 1)

V_CM= ±13 V

V_S= ±2 V to ±20 V 120

R_L= 10 kΩ

R_L= 2 kΩ

2000 4000

±13 ±14

1500 3200

±13 ±14

1200 3200

±13 ±14

V/mV

V

dB

V

µA

V

Input Voltage Range

Common-Mode Rejection

Power Supply Rejection

Output Voltage Swing

120

140

130

114

135

125

114

135

125

±13 ±14

±13 ±13.7

525

±13 ±14

±13 ±13.7

525

±13 ±14

±13 ±13.7

525

V_O

Supply Current Per Amplifier I_SY

Supply Voltage

Slew Rate

Gain Bandwidth Product

Channel Separation

No Load

Operating Range

625

±20

V_S

SR

±2

±20 ±2

0.05 0.15

±20 ±2

0.05 0.15

500

V/µs

kHz

dB

GBWP A_V= +1

CS

500

150

500

150

V

_O= 20 V p–p

150

f_O= 10 Hz

Input Capacitance

C_IN

3

pF

NOTES

¹Guaranteed by CMR test.

Specifications subject to change without notice.

(@ V_S= ؎15 V, –55؇C ≤ T_A≤ +125؇C for OP297A, unless otherwise noted.)

ELECTRICAL CHARACTERISTICS

OP297A

Parameter

Symbol

Conditions

Min

Typ

Max

Units

Input Offset Voltage

Average Input Offset Voltage Drift

Input Offset Current

Input Bias Current

Large-Signal Voltage Gain

Input Voltage Range

Common-Mode Rejection

Power Supply Rejection

Output Voltage Swing

Supply Current Per Amplifier

Supply Voltage

V_OS

TCV_OS

I_OS

45

0.2

60

2700

±13.5

130

125

±13.4

575

100

0.6

450

±450

µV

µV/°C

pA

V/mV

V

dB

V

V_CM= 0 V

V_O= ±10 V, R_L= 2 kΩ

(Note 1)

V_CM= ±13

V_S= ±2.5 V to ±20 V

R_L= 10 kΩ

No Load

I_B

A_VO

IVR

CMR

PSR

V_O

I_SY

V_S

1200

±13

114

±13

750

±20

µA

V

Operating Range

±2.5

NOTES

¹Guaranteed by CMR test.

Specifications subject to change without notice.

–2–

REV. D

8/21/97 4:00 PM

OP297

(@ V = ؎15 V, –40؇C ≤ T ≤ +85؇C for OP297E/F/G, unless otherwise noted.)

ELECTRICAL CHARACTERISTICS

S

A

OP297E

Min Typ Max

OP297F

Min Typ

OP297G

Max Min Typ Max

Parameter

Symbol

Conditions

Units

Input Offset Voltage

Average Input Offset

Voltage Drift

Input Offset Current

Input Bias Current

Large-Signal Voltage Gain

V_OS

35

100

80

300

110

400

µV

TCV_OS

I_OS

I_B

0.2

50

0.6

450

±450

0.5

80

2.0

750

±750

0.6

80

2.0

750

±750 pA

µV/°C

pA

V_CM= 0 V

V_O= ±10 V,

R_L= 2 kΩ

(Note 1)

V_CM= ±13

V_S= ±2.5 V

to ±20 V

A_VO

1200 3200

1000 2500

±13 ±13.5

700

±13

108

2500

±13.5

130

V/mV

V

dB

Input Voltage Range

Common-Mode Rejection

Power Supply Rejection

IVR

CMR

PSR

±13

114

±13.5

130

108

130

114

±13

0.15

±13.4

550

108

0.15

±13 ±13.4

550

108

±13

0.3

±13.4

550

dB

V

µA

V

Output Voltage Swing

Supply Current Per Amplifier I_SY

Supply Voltage

V_O

R_L= 10 kΩ

No Load

Operating Range ±2.5

750

±20

750

±20

750

±20

V_S

±2.5

NOTES

¹Guaranteed by CMR test.

Specifications subject to change without notice.

(@ V_S= ؎15 V, T_A= +25؇C, unless otherwise noted.)

Wafer Test Limits

Parameter

Symbol

Conditions

Limit

Units

Input Offset Voltage

Input Offset Current

V_OS

I_OS

200

µV max

pA max

V_CM= 0 V

V_O= ±10 V, R_L= 2 kΩ

(Note 1)

Input Bias Current

I_B

±200

1200

±13

114

±13

625

pA max

V/mV min

V min

dB min

V min

Large-Signal Voltage Gain

Input Voltage Range

Common-Mode Rejection

Power Supply

Output Voltage Swing

Supply Current Per Amplifier

A_VO

IVR

CMR

PSR

V_O

V_CM= ±13 V

V_S= ±2 V to ±l 8 V

R_L= 2 kΩ

No Load

I_SY

µA max

NOTES

1. Guaranteed by CMR test.

Electrical tests are performed at wafer probe to the limits shown. Due to variations in assembly methods and normal yield loss, yield after packaging is not guaranteed

for standard product dice. Consult factory to negotiate specifications based on dice lot qualifications through sample lot assembly and testing.

DICE CHARACTERISTICS

Dimension shown in inches and (mm).

Contact factory for latest dimensions

+V

OUTPUT A

S

0.118 (3.00)

–INPUT A

+INPUT A

OUTPUT B

–INPUT B

+INPUT B

–V

S

0.074 (1.88)

REV. D

–3–

8/21/97 4:00 PM

OP297

ABSOLUTE MAXIMUM RATINGS¹

3

Package Type

␪

Units

JA

JC

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 V

Input Voltage². . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 V

Differential Input Voltage². . . . . . . . . . . . . . . . . . . . . . . . 40 V

Output Short-Circuit Duration . . . . . . . . . . . . . . . . Indefinite

Storage Temperature Range

Z Package . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to +175°C

P, S Package . . . . . . . . . . . . . . . . . . . . . . . –65°C to +150°C

Operating Temperature Range

OP297A (Z) . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C

OP297E, F (Z) . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C

OP297F, G (P, S) . . . . . . . . . . . . . . . . . . . –40°C to +85°C

Junction Temperature

8-Pin Cerdip (Z)

8-Pin Plastic DIP (P)

8-Pin SO (S)

134

96

150

12

37

41

°C/W

NOTES

¹Absolute maximum ratings apply to both DICE and packaged parts, unless

otherwise noted.

²For supply voltages less than ±20 V, the absolute maximum input voltage is equal

to the supply voltage.

³θ_JAis specified for worst case mounting conditions, i.e., θ_JAis specified for device in

socket for cerdip and P-DIP, packages; θ_JAis specified for device soldered to printed

circuit board for SO package.

Z Package . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to +175°C

P, S Package . . . . . . . . . . . . . . . . . . . . . . . –65°C to +150°C

Lead Temperature Range (Soldering, 60 sec) . . . . . . .+300°C

ORDERING GUIDE¹

Temperature Package

Range

Package

Option¹

Model

Description

OP297AZ

OP297EZ

OP297EP

OP297FP

–55°C to +125°C

–40°C to +85°C

8-Pin Cerdip

8-Pin Plastic DIP

8-Pin SO

8-Pin Plastic DIP

8-Pin SO

Q-8

N-8

SO-8

N-8

SO-8

OP297FS

OP297FS-REEL

OP297FS-REEL7

OP297GP

OP297GS

OP297GS-REEL

OP297GS-REEL7²

8-Pin SO

NOTES

¹Burn-in is available on extended industrial temperature range parts in cerdip, and plastic DIP

packages. For outline information see Package Information section.

²For availability and burn-in information on SO packages, contact your local sales office.

–

1/2

OP-297

V

20V @ 10Hz

p-p

1

+

2kΩ

50kΩ

50Ω

–

1/2

V

2

OP-297

+

V

1

CHANNEL SEPARATION = 20 log

)

V /10000

2

Figure 3. Channel Separation Test Circuit

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 OP297 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.

WARNING!

ESD SENSITIVE DEVICE

–4–

REV. D

8/21/97 4:00 PM

Typical Performance Characteristics–

OP297

400

250

200

150

100

50

400

1200 UNITS

T

V

= +25°C

= ±15V

= 0V

1200

UNITS

T

V

= +25°C

= ±15V

= 0V

A

1200 UNITS

A

T

V

= +25°C

= ±15V

A

S

CM

= 0V

CM

300

200

100

300

200

100

0

–100 –80 –60 –40 –20

0

20 40 60 80 100

–100 –80 –60 –40 –20

0

20 40 60 80 100

–100 –80 –60 –40 –20

0

20 40 60 80 100

INPUT OFFSET VOLTAGE (µV)

INPUT OFFSET CURRENT (pA)

INPUT BIAS CURRENT (pA)

Figure 6. Typical Distribution of In-

put Offset Current

Figure 5. Typical Distribution of Input

Bias Current

Figure 4. Typical Distribution of Input

Offset Voltage

±3

60

T

A

= +25°C

= ±15V

= 0V

I –

T

V

= +25°C

= ±15V

B

A

V

= ±15V

S

V

S

= 0V

CM

40

20

40

20

I –

B

CM

I +

B

I +

B

±2

±1

0

I

OS

I

OS

–20

–40

–60

20

–40

–60

0

1

2

3

4

5

–15 –10

–5

0

5

10

15

–75 –50 –25

0

25 50 75 100 125

TIME AFTER POWER APPLIED (MINUTES)

COMMON-MODE VOLTAGE (VOLTS)

TEMPERATURE (°C)

Figure 9. Input Offset Voltage Warm-

Up Drift

Figure 8. Input Bias, Offset Current

vs. Common-Mode Voltage

Figure 7. Input Bias, Offset Current

vs. Temperature

100

10000

35

BALANCED OR UNBALANCED

30

25

T

= –55°C

= +25°C

A

V

= ±15V

V

= ±15V

S

= 0V

CM

T

A

20

15

10

1

T

= +125°C

1000

100

10

A

10

5

V

S

= ±15V

OUTPUT SHORTED

TO GROUND

0

–5

–10

–15

–20

–25

–30

–35

T

= +125°C

A

–55°C

≤ T ≤ 125°C

A

T

= +25°C

= –55°C

A

T

A

= +25°C

T

0.1

10

100

1k

10k

100k 1M 10M

100

1k

10k 100k

1M

10M 100M

0

1

2

3

4

SOURCE RESISTANCE (Ω)

TIME FROM OUTPUT SHORT (MINUTES)

SOURCE RESISTANCE (Ω)

Figure 10. Effective Offset Voltage

vs. Source Resistance

Figure 11. Effective TCV_OSvs. Source

Resistance

Figure 12. Short Circuit Current vs.

Time, Temperature

REV. D

–5–

8/21/97 4:00 PM

–Typical Performance Characteristics

OP297

1300

1200

1100

1000

900

160

140

120

100

80

140

120

100

80

NO LOAD

T

V

= +25°C

= ±15V

T

V

= +25°C

= ±15V

A

S

T

= +125°C

A

∆V = 10V

S

p-p

T

= +25°C

A

60

–PSR

60

+PSR

100

T

A

= –55°C

±15

40

20

800

0

20

0.1

1

10

1k 10k 100k 1M

1

10

100

1k

10k

100k 1M

0

±5

±10

±20

FREQUENCY (Hz)

SUPPLY VOLTAGE (VOLTS)

Figure 13. Total Supply Current vs.

Supply Voltage

Figure 14. Noise Density vs.

Frequency

Figure 15. Open Loop Gain Linearity

10000

10

100

1000

100

10

T

V

= +25°C

= ±2V TO ±15V

T

= –55°C

A

T

V

= +25°C

= ±2V TO ±20V

A

S

T

= +25°C

S

A

1

0.1

0

= +125°C

CURRENT

NOISE

A

10Hz

1kHz

1000

VOLTAGE

NOISE

100

10

V

= ±15V

= ±10V

S

1kHz

O

10Hz

100

0.01

1

3

1

2

5

10

20

2

10

3

10

4

10

5

10

6

10

7

10

1

10

100

1000

LOAD RESISTANCE (kΩ)

SOURCE RESISTANCE (Ω)

FREQUENCY (Hz)

Figure 17. Total Noise Density vs.

Source Resistance

Figure 18. Maximum Output Swing

vs. Load Resistance

Figure 16. Common-Mode Rejection

vs. Frequency

35

R

V

= 10kΩ

= ±15V

= 0V

T

V

A

= +25°C

= ±15V

= +1

VCL

T

V

A

= +25°C

= ±15V

= +1

L

A

30

25

20

15

10

5

30

25

20

15

10

5

S

V

CM

VCL

T

A

T

A

T

A

= +125°C

= +25°C

= –55°C

1%THD

= 10kΩ

1%THD

= 1kHz

R

f

L

o

0

10

1k

100

LOAD RESISTANCE (Ω)

10k

100

10k

1k

FREQUENCY (Hz)

100k

–15

–10

–5

0

5

10

15

OUTPUT VOLTAGE (VOLTS)

Figure 21. Maximum Output Swing

vs. Frequency

Figure 20. Open Loop Gain vs. Load

Resistance

Figure 19. Power Supply Rejection

vs. Frequency

–6–

REV. D

8/21/97 4:00 PM

OP297

100

1000

100

10

70

60

50

40

30

20

10

0

T

= +25°C

V = ±15V

S

V

C

R

= ±15V

= 30pF

= 1MΩ

T

= +25°C

= ±15V

–EDGE

A

S

A

80

V

A

V

L

S

GAIN

= +1

= 100mV

VCL

OUT

60

p-p

+EDGE

PHASE

40

90

T

= –55°C

A

1

20

0

135

180

225

0.1

0.01

0.001

–20

–40

T

= +125°C

A

10

100

1k

10k

100k

100

1M

1k

10k

100

1M

10M

10

1000

100

10000

FREQUENCY (Hz)

LOAD CAPACITANCE (pF)

FREQUENCY (Hz)

Figure 23. Small Signal Overshoot

vs. Capacitance Load

Figure 24. Open Loop Output

Impedance vs Frequency

Figure 22. Open Loop Gain,

Phase vs. Frequency

APPLICATIONS INFORMATION

Extremely low bias current over the full military temperature

range makes the OP297 attractive for use in sample-and-hold

amplifiers, peak detectors, and log amplifiers that must operate

over a wide temperature range. Balancing input resistances is

not necessary with the OP297 Offset voltage and TCV_OSare

degraded only minimally by high source resistance, even when

unbalanced.

100

90

The input pins of the OP297 are protected against large differ-

ential voltage by back-to-back diodes and current-limiting resis-

tors. Common-mode voltages at the inputs are not restricted,

and may vary over the full range of the supply voltages used.

10

0%

20mV

5µs

The OP297 requires very little operating headroom about the

supply rails, and is specified for operation with supplies as low

as +2 V. Typically, the common-mode range extends to within

one volt of either rail. The output typically swings to within one

volt of the rails when using a 10 kΩ load.

Figure 26. Small-Signal Transient Response

(C_LOAD= 1000 pF, A_VCL= +1)

100

90

AC PERFORMANCE

The OP297’S AC characteristics are highly stable over its full

operating temperature range. Unity-gain small-signal response is

shown in Figure 25. Extremely tolerant of capacitive loading on

the output, the OP297 displays excellent response even with

1000 pF loads (Figure 26).

10

0%

20mV

5µs

100

90

Figure 27. Large-Signal Transient Response

(A_VCL= +1)

GUARDING AND SHIELDING

To maintain the extremely high input impedances of the

OP297, care must be taken in circuit board layout and manu-

10

0%

facturing. Board surfaces must be kept scrupulously clean and

free of moisture. Conformal coating is recommended to provide

20mV

5µs

Figure 25. Small-Signal Transient Response

(C_LOAD= 100 pF, A_VCL= +1)

REV. D

–7–

8/21/97 4:00 PM

OP297

UNITY-GAIN FOLLOWER

NONINVERTING AMPLIFIER

–

1/2

OP-297

+

INVERTING AMPLIFIER

MINI-DIP

BOTTOM VIEW

8

1

–

1/2

OP-297

A

+

B

Figure 28. Guard Ring Layout and Connections

APPLICATIONS

a humidity barrier. Even a clean PC board can have 100 pA of

leakage currents between adjacent traces, so guard rings should

be used around the inputs. Guard traces are operated at a volt-

age close to that on the inputs, as shown in Figure 28, so that

leakage currents become minimal. In noninverting applications,

the guard ring should be connected to the common-mode volt-

age at the inverting input. In inverting applications, both inputs

remain at ground, so the guard trace should be grounded. Guard

traces should be on both sides of the circuit board.

PRECISION ABSOLUTE VALUE AMPLIFIER

The circuit of Figure 30 is a precision absolute value amplifier

with an input impedance of 30 MΩ. The high gain and low

TCV_OSof the OP297 insure accurate operation with microvolt

input signals. In this circuit, the input always appears as a

common-mode signal to the op amps. The CMR of the OP297

exceeds 120 dB, yielding an error of less than 2 ppm.

+15V

C

2

OPEN-LOOP GAIN LINEARITY

0.1µF

The OP297 has both an extremely high gain of 2000 V/mV

minimum and constant gain linearity. This enhances the preci-

sion of the OP297 and provides for very high accuracy in high

closed loop gain applications. Figure 29 illustrates the typical

open-loop gain linearity of the OP297 over the military tempera-

ture range.

R

3

1

1kΩ

D

C

30pF

1

6

5

–

1N4148

8

1/2

OP-297

2

3

7

–

D

2

1/2

OP-297

1

0V < V

< 10V

OUT

+

V

+

IN

1N4148

C

3

4

R

2

R

= 10kΩ

= ±15V

= 0V

L

2kΩ

V

S

0.1µF

CM

T

= +125°C

= +25°C

= –55°C

A

–15V

Figure 30. Precision Absolute Value Amplifier

PRECISION CURRENT PUMP

Maximum output current of the precision current pump shown

in Figure 31 is ±10 mA. Voltage compliance is ± 10 V with

±15 V supplies. Output impedance of the current transmitter

exceeds 3 MΩ with linearity better than 16 bits.

–15

–10

–5

0

5

10

15

OUTPUT VOLTAGE (VOLTS)

Figure 29. Open-Loop Linearity of the OP297

–8–

REV. D

8/21/97 4:00 PM

OP297

PRECISION POSITIVE PEAK DETECTOR

In Figure 32, the C_Hmust be of polystyrene, Teflon^®*, or poly-

ethylene to minimize dielectric absorption and leakage. The

droop rate is determined by the size of C_Hand the bias current

of the OP297.

SIMPLE BRIDGE CONDITIONING AMPLIFIER

Figure 33 shows a simple bridge conditioning amplifier using

the OP297. The transfer function is:

∆R R_F

V_OUT=V_REF

R + ∆R

R

3

The REF43 provides an accurate and stable reference voltage

for the bridge. To maintain the highest circuit accuracy, R_F

should be 0.1% or better with a low temperature coefficient.

10kΩ

R

1

2

3

–

+

–

R

5

10kΩ

R

2

1/2

1

I

OUT

V

IN

OP-297

1kΩ

±10mA

100Ω

+

+15V

8

10kΩ

+15V

1N4148

0.1µF

2

5

6

–

+

1/2

6

5

1

8

–

2N930

R

4

OP-297

+

1kΩ

1/2

OP-297

7

3

1/2

OP-297

7

V

OUT

IN

1kΩ

+

4

10kΩ

0.1µF

–

C

H

4

–15V

RESET

1kΩ

V

IN

100Ω

IN

I

=

= 10mA/V

OUT

R

–15V

5

Figure 32. Precision Positive Peak Detector

Figure 31. Precision Current Pump

+5V

2

V

REF

2.5V

R

6

R

F

REF-43

4

R

2

3

–

1

1/2

OP-297

V

OUT

R

R + ∆R

+

+5V

∆R

R

F

V

REF

=

OUT

(

R + ∆R

R

6

5

8

–

1/2

OP-297

7

+

4

–5V

Figure 33. A Simple Bridge Conditioning Amplifier Using the OP297

*Teflon is a registered trademark of the Dupont Company

REV. D

–9–

8/21/97 4:00 PM

OP297

Exponentiating both sides of the equation leads to:

NONLINEAR CIRCUITS

Due to its low input bias currents, the OP297 is an ideal log

amplifier in nonlinear circuits such as the square and square-

root circuits shown in Figures 34 and 35. Using the squaring

circuit of Figure 34 as an example, the analysis begins by writing

a voltage loop equation across transistors Q₁, Q₂, Q₃and Q₄.

2

(I_IN

)

I_O

=

I_REF

Op amp A₂forms a current-to-voltage converter which gives

_OUT= R2 × 10. Substituting (V_IN/R1) for I_INand the above

V

equation for I_Oyields:

I_IN

I_S1

I_IN

I_S2

I_O

I_S3

I_REF

I_S4

V_T1ln

+V_T2ln

=V_T3ln

+V_T4ln

2

R2 V_IN

I_REFR1

V_OUT

=

All the transistors of the MAT04 are precisely matched and at

the same temperature, so the I_Sand V_Tterms cancel, giving:

A similar analysis made for the square-root circuit of Figure 35

leads to its transfer function:

2 ln I_IN= ln I_O+ ln I_REF= ln (I_O× I_REF

)

(V_IN)(I_REF

R1

)

V_OUT= R2

C

2

100pF

R

2

33kΩ

6

5

–

1/2

OP-297

2

7

V

OUT

I

O

A

+

1

2

Q

1

7

3

6

Q

2

5

MAT-04E

C

1

14

Q

13

8

Q

I

4

REF

9

100pF

3

V+

8

12

10

R

1

I

IN

2

3

–

V

IN

R

3

1/2

33kΩ

1

OP-297

A

+

50kΩ

1

R

4

50kΩ

–15V

V–

Figure 34. Squaring Amplifier

–10–

REV. D

8/21/97 4:00 PM

OP297

R

2

33kΩ

C

2

100pF

6

5

–

7

1/2

OP-297

V

OUT

I

O

+

MAT-04E

Q

1

3

1

I

IN

REF

2

6

C

1

14

13

9

Q

4

100pF

V+

12

7

8

Q

3

2

R

10

5

1

2

8

–

V

IN

R

3

5

33kΩ

1

1/2

OP-297

3

50kΩ

2kΩ

R

4

+

4

50kΩ

–15V

V–

Figure 35. Square-Root Amplifier

In these circuits, I_REFis a function of the negative power supply.

To maintain accuracy, the negative supply should be well regu-

lated. For applications where very high accuracy is required, a

voltage reference may be used to set I_REF. An important consid-

eration for the squaring circuit is that a sufficiently large input

voltage can force the output beyond the operating range of the

output op amp. Resistor R4 can be changed to scale I_REF, or R1,

and R2 can be varied to keep the output voltage within the

usable range.

OP297 SPICE MACRO-MODEL

Figures 36 and 37 show the node end net list for a SPICE

macro model of the OP297. The model is a simplified version of

the actual device and simulates important dc parameters such as

V_OS, I_OS, I_B, A_VO, CMR, V_Oand I_SY. AC parameters such as

slew rate, gain and phase response and CMR change with fre-

quency are also simulated by the model.

The model uses typical parameters for the OP297. The poles

and zeros in the model were determined from the actual open

and closed-loop gain and phase response of the OP297. In this

way, the model presents an accurate ac representation of the

actual device. The model assumes an ambient temperature

of 25°C.

Unadjusted accuracy of the square-root circuit is better than

0.1% over an input voltage range of 100 mV to 10 V. For a

similar input voltage range, the accuracy of the squaring circuit

is better than 0.5%.

REV. D

–11–

8/21/97 4:00 PM

OP297

99

R

6

V

3

4

2

–

13

C

R

4

C

2

D

3

5

12

8

15

16

R

2

1

IN2

8

Q

R

7

G

–IN

1

C

3

2

E

1

9

1

–

R

3

1

11

R

10

R

I

D

2

D

1

C

IN

OS

98

5

4

6

E

REF

D

4

R

–

2

R

IN1

+IN

14

– +

9

7

E

OS

V

I

3

1

–

50

C

6

C

7

R

11

R

13

22

17

R

15

R

10

G

3

R

12

R

14

G

C

8

C

5

E

2

E

3

2

–

98

99

D

7

D

8

G

R

18

R

16

6

I

SY

D

5

V

4

26

27

+

–

22

25

L

1

23

D

6

V

5

–

+

28

29

R

19

R

17

G

5

D

9

D

7

4

10

50

Figure 36. OP297 Macro-Model

–12–

REV. D

8/21/97 4:00 PM

OP297

Table I. SPICE Net-List

• POLE AT 1.8 MHz

OP297 SPICE MACRO-MODEL

•

• NODE ASSIGNMENTS

•

R10

C5

G2

•

17 98 1E6

17 98 88 4E-15

98 17 16 23 1 E-6

•NONINVERTING INPUT

INVERTING INPUT

OUTPUT

• COMMON-MODE GAIN NETWORK WITH ZERO AT 50 HZ

•

POSITIVE SUPPLY

NEGATIVE SUPPLY

R11

C6

R12

E2

•

18 19 1E6

18 19 3.183E-9

•

SUBCKT OP297 1 2 30 99 50

19 98

1

INPUT STAGE & POLE AT 6 MHz

•

18 98 3 23 100E-3

RIN1

RIN2

R1

R2

R3

1

2

8

7

5

6

7

8

3

2500

5E11

• POLE AT 6 MHz

•

R15

C8

G3

•

22 98 1E6

22 98 26.53E-15

98 22 17 23 1 E-6

99 612

R4

CIN

C2

7

5

8

6

3E-12

21.67E-12

• OUTPUT STAGE

•

I1

4

7

9

5

50 0.1E-3

R16

R17

ISY

R18

R19

L1

G4

G5

G6

G7

V4

23 99 160K

23 50 160K

99 50 331 E-6

25 99 200

IOS

EOS

Q1

Q2

R5

8

7

8

9

4

9

8

20E-12

POLY(1) 19 23 25E-6

10 QX

11 QX

96

1

6

25 50 200

10

11

8

25 30 1 E-7

28 50 22 25 5E-3

29 50 25 22 5E-3

25 99 99 22 5E-3

50 25 22 50 5E-3

26 25 1.8

R6

96

DX

D1

D2

•

EREF 98

•

9

0

23

0

1

V5

25 27 1.3

GAIN STAGE & DOMINANT POLE AT 0.13 HZ

•

D5

D6

D7

D8

D9

D10

•

22 26 DX

27 22 DX

99 28 DX

99 29 DX

50 28 DY

50 29 DY

R7

C3

G1

12 98 2.45E9

12 98 500E-12

98 12 5 6 1.634E-3

V2

V3

D3

D4

•

99 13 1.5

14 50 1.5

12 13 DX

14 12 DX

• MODELS USED

•

• MODEL QX NPN BF=2.5E6)

• MODEL DX D IS = 1 E-15)

• MODEL DY D IS = 1 E-15 BV = 50)

• ENDS OP297

• NEGATIVE ZERO AT -1 8 MHz

•

R8

C4

R9

E1

•

15 16 1E6

15 16 –88.4E-15

16 98

1

15 98 12 23 1E6

REV. D

–13–

8/21/97 4:00 PM

OP297

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

8-Lead Plastic DIP

(N-8)

0.430 (10.92)

0.348 (8.84)

8

5

4

0.280 (7.11)

0.240 (6.10)

1

0.325 (8.25)

0.300 (7.62)

0.060 (1.52)

0.015 (0.38)

PIN 1

0.195 (4.95)

0.115 (2.93)

0.210 (5.33)

MAX

0.130

(3.30)

MIN

0.160 (4.06)

0.115 (2.93)

0.015 (0.381)

SEATING

PLANE

0.100

(2.54)

BSC

0.022 (0.558)

0.014 (0.356)

0.070 (1.77)

0.045 (1.15)

0.008 (0.204)

8-Lead Cerdip

(Q-8)

0.055 (1.4)

MAX

0.005 (0.13)

MIN

8

5

0.310 (7.87)

0.220 (5.59)

1

4

PIN 1

0.320 (8.13)

0.290 (7.37)

0.405 (10.29)

MAX

0.060 (1.52)

0.015 (0.38)

0.200 (5.08)

MAX

0.150

(3.81)

MIN

0.200 (5.08)

0.125 (3.18)

0.015 (0.38)

0.008 (0.20)

SEATING

0.070 (1.78)

0.023 (0.58)

0.100

(2.54)

BSC

15°

0°

PLANE

0.014 (0.36)

0.030 (0.76)

8-Lead Narrow Body (SOIC)

(SO-8)

0.1968 (5.00)

0.1890 (4.80)

8

1

5

4

0.1574 (4.00)

0.1497 (3.80)

0.2440 (6.20)

0.2284 (5.80)

PIN 1

0.0688 (1.75)

0.0532 (1.35)

0.0196 (0.50)

x 45°

0.0098 (0.25)

0.0040 (0.10)

0.0099 (0.25)

8°

0°

0.0500

(1.27)

BSC

0.0192 (0.49)

0.0138 (0.35)

SEATING

PLANE

0.0098 (0.25)

0.0075 (0.19)

0.0500 (1.27)

0.0160 (0.41)

–14–

REV. D

–15–

8/21/97 4:00 PM

OP297

–16–

REV. D

型号:	OP297GP
是否Rohs认证：	不符合
生命周期：	Transferred
Reach Compliance Code：	unknown
风险等级：	5.67
放大器类型：	OPERATIONAL AMPLIFIER
架构：	VOLTAGE-FEEDBACK
25C 时的最大偏置电流 (IIB)：	0.0002 µA
频率补偿：	YES
最大输入失调电压：	400 µV
JESD-30 代码：	R-PDIP-T8
JESD-609代码：	e0
低-偏置：	YES
低-失调：	YES
标称负供电电压 (Vsup)：	-15 V
功能数量：	2
端子数量：	8
最高工作温度：	85 °C
最低工作温度：	-40 °C
封装主体材料：	PLASTIC/EPOXY
封装代码：	DIP
封装等效代码：	DIP8,.3
封装形状：	RECTANGULAR
封装形式：	IN-LINE
电源：	+-15 V
认证状态：	Not Qualified
最小摆率：	0.05 V/us
子类别：	Operational Amplifiers
最大压摆率：	1.5 mA
供电电压上限：	20 V
标称供电电压 (Vsup)：	15 V
表面贴装：	NO
技术：	BIPOLAR
温度等级：	INDUSTRIAL
端子面层：	Tin/Lead (Sn/Pb)
端子形式：	THROUGH-HOLE
端子节距：	2.54 mm
端子位置：	DUAL
最小电压增益：	800000
Base Number Matches：	1

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