OP27A Datasheet, PDF (16/21 Pages) Texas Instruments – LOW-NOISE HIGH-SPEED PRECISION OPERATIONAL AMPLIFIERS

OP27A, OP27C, OP27E, OP27G
OP37A, OP37C, OP37E, OP37G
LOW-NOISE HIGH-SPEED PRECISION OPERATIONAL AMPLIFIERS
SLOS100B – FEBRUARY 1989 – REVISED AUGUST 1994
TYPICAL CHARACTERISTICS
OP37
VOLTAGE-FOLLOWER
SMALL-SIGNAL PULSE RESPONSE
80
OP37
VOLTAGE-FOLLOWER
LARGE-SIGNAL PULSE RESPONSE
8
60
6
40
4
20
2
0
0
– 20
–2
– 40
VCC _± = ± 15 V
AV = 5
– 60
CL = 15 pF
TA = 25°C
– 80
0 0.2 0.4 0.6 0.8 1 1.2
t – Time – µs
Figure 32
–4
VCC _± = ± 15 V
–6
AV = 5
TA = 25°C
–8
0123456
t – Time – µs
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.
2–16
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265
• POST OFFICE BOX 1443 HOUSTON, TEXAS 77251–1443