OP27A, OP27C, OP27E, OP27G

OP37A, OP37C, OP37E, OP37G

LOW-NOISE HIGH-SPEED PRECISION OPERATIONAL AMPLIFIERS

SLOS100B – FEBRUARY 1989 – REVISED AUGUST 1994

2–16

POST OFFICE BOX 655303

POST OFFICE BOX 1443

TYPICAL CHARACTERISTICS

OP37

VOLTAGE-FOLLOWER

SMALL-SIGNAL PULSE RESPONSE

80

60

40

20

0

– 20

– 40

– 60

– 80

t – Time –

µs

0

0.2

0.4

0.6

0.8

1

1.2

VCC

± = ±15 V

AV = 5

CL = 15 pF

TA = 25°C

OP37

VOLTAGE-FOLLOWER

LARGE-SIGNAL PULSE RESPONSE

8

6

4

0

– 2

– 4

– 6

– 8

2

t – Time –

µs

012

345

6

VCC

± = ±15 V

AV = 5

TA = 25°C

Figure 32

Figure 33

APPLICATION INFORMATION

general

The OP27 and OP37 series devices can be inserted directly onto OP07, OP05,

µA725, and SE5534 sockets

with or without removing external compensation or nulling components. In addition, the OP27 and OP37 can

be fitted to

µA741 sockets by removing or modifying external nulling components.

noise testing

Figure 34 shows a test circuit for 0.1-Hz to 10-Hz peak-to-peak noise measurement of the OP27 and OP37. The

frequency response of this noise tester indicates that the 0.1-Hz corner is defined by only one zero. Because

the time limit acts as an additional zero to eliminate noise contributions from the frequency band below 0.1 Hz,

the test time to measure 0.1-Hz to 10-Hz noise should not exceed 10 seconds.

Measuring the typical 80-nV peak-to-peak noise performance of the OP27 and OP37 requires the following

special test precautions:

1.

The device should be warmed up for at least five minutes. As the operational amplifier warms up, the

offset voltage typically changes 4

µV due to the chip temperature increasing from 10°C to 20°C starting

from the moment the power supplies are turned on. In the 10-s measurement interval, these

temperature-induced effects can easily exceed tens of nanovolts.

2.

For similar reasons, the device should be well shielded from air currents to eliminate the possibility of

thermoelectric effects in excess of a few nanovolts, which would invalidate the measurements.

3.

Sudden motion in the vicinity of the device should be avoided, as it produces a feedthrough effect that

increases observed noise.