Linear Technology: A/D converter tops all for accuracy, speed

The LTC2378-20 from Linear Technology is a real 20-bit A/D converter, with industry-leading 0.5-ppm integral nonlinearity. Yes, that's in PPM ¯ otherwise called 0.00005%. And, in an industry first, this exceptional linearity comes in a SAR-type A/D with 1 Msample/s speeds. And yes, the INL spec is at full speed. This is a breakthrough device for many applications.

Worst-case INL is 2 ppm over the -40° to 85°C temperature range. The 16-lead DFN- or MSOP-packaged IC yields a 104-dB SNR and requires just 21 mW at 1 Msample/s and only 21 μW at 1 ksamples/s.

A number of medical and industrial applications currently use multiple A/Ds to get the combination of speed and accuracy they need. This IC is so fast they can go to a single A/D — and it is so very accurate that they probably don't have to do any time-consuming calibration on the assembly line anymore. Think about that. At $29.50 each, the A/D is not a low-cost item, but it certainly might be well worth it.