Bipolar/JFET, Audio Operational Amplifier

The OP176 is a low noise, high output drive op amp that features 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 previous audio amplifiers, but at much lower supply currents.

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 OP176 to be used in many dc coupled or summing applications without the need for special selections or the added noise of additional offset adjustment circuitry.

The output is capable of driving 600 Ohm loads to 10 V rms while maintaining low distortion. THD + Noise at 3 V rms is a low 0.0006%.

The OP176 is specified over the extended industrial (-40°C to +85°C) temperature range. OP176s are available in both plastic DIP and SO-8 packages. SO-8 packages are available in 2500 piece reels. Many audio amplifiers are not offered in SO-8 surface mount packages for a variety of reasons, however, the OP176 was designed so that it would offer full performance in surface mount packaging.