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 JFET's. Total Harmonic Distortion plus Noise equals that of previous audio amplifiers, but at much lower supply currents.
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 1kHz, it is only 6 nV/(root)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 22 V/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 5mA of supply current, lower than any standard audio amplifier.
Improved dc performance is also provided with bias and offset currents greatly reduced over purely bipolar designs. Input offset voltage is guaranteed at 1mV and is typically less than 200µV. This allows the OP275 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 os 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 OP275 is specified over the extended industrial (-40°C to +85°C) temperature range. OP275s are availale in both plastic 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.
|Title||Content Type||File Type|
|OP275: Dual Bipolar/JFET, Audio Operational Amplifier Data Sheet (Rev C, 02/2004) (pdf, 416 kB)||Data Sheets|
|AN-940: Low Noise Amplifier Selection Guide for Optimal Noise Performance (pdf, 199 kB)||Application Notes|
|AN-649: Using the Analog Devices Active Filter Design Tool (pdf, 5301 kB)||Application Notes|
|AN-356: User's Guide to Applying and Measuring Operational Amplifier Specifications (pdf, 538 kB)||Application Notes|
|AN-211: The Alexander Current-Feedback Audio Power Amplifier (pdf, 1154 kB)||Application Notes|
Ask The Applications Engineer-25
Op Amps Driving Capacitive Loads
(Analog Dialogue, Vol. 31, No. 2, 1997)
Ask The Applications Engineer-13
Confused About Amplifier Distortion Specs?
(Analog Dialogue, 30th Anniversary Reader Bonus)
|RAQs index||Rarely Asked Questions||HTML|
|Glossary of EE Terms||Glossary||HTML|
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Analog Filter Wizard 2.0
The Analog Filter Wizard™ helps you design a low-pass, high-pass, band-pass or band-stop filter with actual op amps. It then simulates the filter’s performance with these op amps in real time. You can ask the tool to optimize for power, noise, or voltage range, and it will pick op amps and passive components appropriately. Or you can adjust the components manually yourself.
|ADIsim Design/Simulation Tools||HTML|
|OP275 SPICE Macro-Model||SPICE Models||HTML|
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.