rsdio writes: These are potentially overkill for most DIY, but if you really need small size, low noise, and/or rail-to-rail performance, then they might be just the ticket. Probably a great choice for a DSO front end. With low power, particularly USB 5 V, rail-to-rail capabilities can be really important.
Low-Noise, CMOS-Input, Rail-to-Rail Op Amps Extend Battery Life in Portable Medical Applications
MAX9636–MAX9638, rail-to-rail, low-noise operational amplifiers. Offered in 6-pin SC70 (single), 8-pin SC70 (dual), and 10-pin UTQFN (dual) packages, these devices minimize board space while delivering outstanding noise performance. With 38nV/ input-voltage noise density, 0.9fA/ input-current noise density, and 0.1pA input-bias current, the MAX9636–MAX9638 facilitate interfacing to high-impedance sources such as photodiode and piezoelectric sensors. Maxim’s proprietary BiCMOS process technology and design architectures enable these devices to achieve an excellent combination of size, low-noise performance, bandwidth, and supply current.
Not such a great choice as a DSO front end: it features a “wide” (!!!) bandwidth of 1.5 MHz only.
But yes, it may be useful in other low-power designs.
I don’t consider 38 nV/sqrt(Hz) as ‘low’ voltage noise, either. It may be lower than other micropower amps, but unless power is the overriding concern, there are better choices.
The current noise spec is quite good, so it should be a good choice for high impedance sources as long as a really high dynamic range is not required.
MAX9636, avail:0
MAX9637, avail:0
MAX9638, avail:0
More Maxim “Unobtainium”…