OP270GS(RevA) データシートの表示（PDF） - Analog Devices

部品番号

コンポーネント説明

メーカー

OP270GS
(Rev.:RevA)

Dual Very Low Noise Precision Operational Amplifier

Analog Devices 

OP270

100

10 OP200

OP270

RESISTOR

NOISE ONLY

1

100

1k

10k

RS – SOURCE RESISTANCE (⍀)

100k

Figure 4. Total Noise vs Source Resistance (In-

cluding Resistor Noise) at 10Hz

1000

OP200

100

OP270

RESISTOR

NOISE ONLY

10

100

1k

10k

RS – SOURCE RESISTANCE (⍀)

100k

Figure 5. Peak-To-Peak Noise (0.1Hz To 10Hz)

vs Source Resistance (Includes Resistor Noise)

Figure 5 shows peak-to-peak noise versus source resistance over the

0.1 Hz to 10Hz range. Once again, at low values of RS, the voltage

noise of the OP270 is the major contributor to peak-to-peak

noise with current noise the major contributor as RS increases.

The crossover point between the OP270 and the OP200 for

peak-to-peak noise is at RS = 17 kW.

The OP271 is a higher speed version of the OP270, with a slew

rate of 8V/ms. Noise of the OP271 is slightly higher than the

OP270. Like the OP270, the OP271 is unity-gain stable.

For reference, typical source resistances of some signal sources

are listed in Table I.

TABLE I

DEVICE

Strain gauge

Magnetic

tapehead,

microphone

SOURCE

IMPEDANCE

<500W

<1500W

Magnetic

phonograph

cartridge

<1500W

Linear variable <1500W

differential

transformer

COMMENTS

Typically used in low

frequency applications.

Low IB very important to

reduce self-magnetization

problems when direct

coupling is used. OP270 IB

can be neglected.

Similar need for low IB in

direct coupled applications.

OP270 will not introduce any

self-magnetization problem.

Used in rugged servo-feedback

applications. Bandwidth of

interest is 400 Hz to 5 kHz.

For further information regarding noise calculations, see “Minimi-

zation of Noise in Op-Amp Applications”, Application Note AN15.

R3

1.24k⍀

R1

5⍀

–

R2

5⍀

OP270

DUT

+

+

OP27E

– R5

909⍀

R4

200⍀

C1

2␮F

R6

600⍀

D1, D2

1N4148

R8

10k⍀

+

OP27E

– R9

306k⍀

C2

0.032␮F

C4

0.22␮F

R10

65.4k⍀

R11

65.4k⍀

C3

0.22␮F

+

OP42E

–

R13

5.9k⍀

R12

10k⍀

R14

4.99k⍀

eOUT

C5

1␮F

GAIN = 50,000

VS = ؎15V

Figure 6. Peak-To-Peak Voltage Noise Test Circuit (0.1 Hz To 10Hz)

–10–

REV. A

Share Link: