The MAX125/MAX126 are high-speed, multichannel,14-bit data-acquisition systems (DAS) with simultaneoustrack/holds (T/Hs). These devices contain a 14-bit, 3µs,successive-approximation analog-to-digital converter(ADC), a +2.5V reference, a buffered reference input,and a bank of four simultaneous-sampling T/H amplifiersthat preserve the relative phase information of thesampled inputs. The MAX125/MAX126 have two multiplexedinputs for each T/H, allowing a total of eightinputs. In addition, the converter is overvoltage tolerantto ±17V; a fault condition on any channel will not harmthe IC. Available input ranges are ±5V (MAX125) and±2.5V (MAX126).

An on-board sequencer converts one to four channelsper active-low CONVST pulse. In the default mode, one T/H output(CH1A) is converted. An interrupt signal (active-low INT) is providedafter the last conversion is complete. Convert two,three, or four channels by reprogramming theMAX125/MAX126 through the bidirectional parallelinterface. Once programmed, the MAX125/MAX126continue to convert the specified number of channelsper active-low CONVST pulse until they are reprogrammed.The channels are converted sequentially, beginning withCH1. The INT signal always follows the end of the lastconversion in a conversion sequence. The ADC convertseach assigned channel in 3µs and stores theresult in an internal 14x4 RAM. Upon completion of theconversions, data can be accessed by applying successivepulses to the active-low RD pin. Four successive readsaccess four data words sequentially.

The parallel interface's data-access and bus-releasetiming specifications are compatible with most populardigital signal processors and 16-bit/32-bit microprocessors,so the MAX125/MAX126 conversion results can beaccessed without resorting to wait states.