Dual Bipolar/JFET, Audio
Operational Amplifier
OP275*
FEATURES
PIN CONNECTIONS
Excellent Sonic Characteristics
Low Noise: 6 nV/ Hz
8-Lead Narrow-Body SOIC
(S Suffix)
8-Lead PDIP
(P Suffix)
Low Distortion: 0.0006%
High Slew Rate: 22V/s
Wide Bandwidth: 9 MHz
Low Supply Current: 5 mA
Low OffsetVoltage: 1 mV
Low Offset Current: 2 nA
Unity Gain Stable
1
8
7
6
5
OUT A
–IN A
+IN A
V–
V+
OP275
8
V+
1
2
3
4
OUT A
–IN A
+IN A
V–
2
3
4
OUT B
–IN B
+IN B
OP275
7
6
5
OUT B
–IN B
+IN B
SOIC-8 Package
PDIP-8 Package
APPLICATIONS
High Performance Audio
Active Filters
Fast Amplifiers
Integrators
GENERAL DESCRIPTION
Improved dc performance is also provided with bias and offset
currents greatly reduced over purely bipolar designs. Input offset
voltage is guaranteed at 1 mV and is typically less than 200 µV.
This allows the OP275 to be used in many dc-coupled or sum-
ming applications without the need for special selections or the
added noise of additional offset adjustment circuitry.
The OP275 is the first amplifier to feature the Butler Amplifier
front end.This new front end design combines both bipolar
and JFET transistors to attain amplifiers with the accuracy and
low noise performance of bipolar transistors, and the speed and
sound quality of JFETs. Total Harmonic Distortion plus Noise
equals that of previous audio amplifiers, but at much lower
supply currents.
The output is capable of driving 600 loads to 10V rms while
maintaining low distortion.THD + Noise at 3V rms is a low
0.0006%.
A very low l/f corner of below 6 Hz maintains a flat noise density
response.Whether noise is measured at either 30 Hz or 1 kHz,
The OP275 is specified over the extended industrial (–40°C to
+85°C) temperature range. OP275s are available in both plas-
tic DIP and SOIC-8 packages. SOIC-8 packages are available
in 2500-piece reels. Many audio amplifiers are not offered
in SOIC-8 surface-mount packages for a variety of reasons;
however, the OP275 was designed so that it would offer full
performance in surface-mount packaging.
it is only 6 nV Hz.The JFET portion of the input stage gives
the OP275 its high slew rates to keep distortion low, even when
large output swings are required, and the 22V/µs slew rate of the
OP275 is the fastest of any standard audio amplifier. Best of all,
this low noise and high speed are accomplished using less than
5 mA of supply current, lower than any standard audio amplifier.
*Protected by U.S. Patent No. 5,101,126.
REV.C
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