Demonstration circuit 742B features the LTC2449, an 8-/16-channel, high speed, 24-bit ΔΣ ADC with ten selectable speed/resolution modes from 6.9Hz/200nVRMS to 3.5kHz/25μVRMS (4kHz with external oscillator). Key DC specifications include 5ppm INL, 5μV offset, 10ppm fullscale error and 20nV/°C offset drift. In the 6.9Hz/200nVRMS mode, input normal mode rejection of 50Hz and 60Hz noise is better than 87dB. The accuracy (offset, full-scale, linearity, drift) and power dissipation are independent of the speed selected. The LTC2449 performs auto-zeroing of the ADC by reversing the inputs through the multiplexer output/ADC input connections. This allows an external dual buffer amplifier to isolate the signal inputs from the sampling current of the ADC.