KAD/ADC/141 16 channel ¼-bridge ADC

16 channel, ¼-bridge ADC (current excitation, RTD temp. sensors, 3.125kHz b/w) - 16ch at 12.5ksps

The KAD/ADC/141 provides independent excitation for up to 16 channels and is intended for RTD type sensors. Each channel has a separate programmable digital filter and A/D converter.

At the heart of the KAD/ADC/141 is a hard-wired state-machine that oversamples all channels at a rate between 50ksps and 100ksps and digitally filters any noise above the user-programmable cutoff frequency. This is achieved using cascaded, half-band, finite-impulse-response filters followed by an 8th order Butterworth infinite-impulse-response filter with a default cutoff point set at one quarter of the sampling frequency (fc = fs / 4).

All signals are sampled simultaneously. Thus, when several channels are sampled at different sampling rates, at the start of an acquisition cycle, all channels are aligned.

The excitation current through the RTD is kept constant. As the resistance changes, the voltage across the RTD (and hence as seen by the amplifier) changes linearly.

A linearization table for each channel can be used to compensate for non-linear sensors or to fine-tune gain and offset.