Low Noise OP amp

Low noise and moderate cost are subjective terms. What constitutes low noise for your application? Are you looking for voltage offsets in the microvolt or milivolt range, current offsets in the pico amp, nanoamp, or miliamp range? What is the required bandwidth and slew rate? These are some of the factor that need to be considered in proper part selection.

Unless you have a solid understanding of your noise (margin) requirments, it is impossible not only to suggest a part that will meet your needs, but for you to be sure that it does. Often times, the critical parameters depend on the circuit implementation. The only likely effect of simply inserting precision components without this understanding is an increase in cost without a performance gain.

Right. For example, the NE5532A mentioned in this thread is a classic "quiet", "low-distortion" opamp, but for some uses it's very noisy (8nV and 2.7pA per root Hz at 30Hz), and for other uses it's not a low-distortion opamp. Many wouldn't consider it a low-cost opamp, 84-cents for TI's miniDIP version at Digikey.

It depends, you havent stated source impedance, frequency range etc. but if it is for audio, NE5534 is cheap and good

see a rundown here

martin

My current favorite (well, voltage favorite) is the LT1677. A rail-to- rail OP27.

-- jm

------------------------------------------------------

------------------------------------------------------

NE5532

Ian

The answer depends entirely on the bandwidth, the frequency, and the source impedance.

But Linear Systems is a good starting place.

-- Many thanks,

Don Lancaster voice phone: (928)428-4073 Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552 rss:

Please visit my GURU's LAIR web site at

Most people asking this question are starting with an input whose signal to noise ratio is already terrible.

For these folks, a low noise op amp makes no difference whatsoever.

LT1028 or AD797

AD797 is not exactly low cost

martin

........... Phil

"Ian Bell"

The f****it OP asked for one.

......... Phil ;-)

True but the OP was after a "moderate cost" one. Since "moderate" isn't well defined, I thought it worth suggesting the AD797