ZHCSID7 June 2018 ADS8688AT
PRODUCTION DATA.
The ADS8688AT features an integrated 8-channel analog multiplexer. For each analog input channel, the voltage difference between the positive analog input AIN_nP and the negative ground input AIN_nGND is conditioned by the analog front-end circuitry before being fed into the multiplexer. The output of the multiplexer is directly sampled by the ADC. The multiplexer in the device can scan these analog inputs in either manual or auto-scan mode, as explained in the Channel Sequencing Modes section. In manual mode (MAN_Ch_n), the channel is selected for every sample via a register write; in auto-scan mode (AUTO_RST), the channel number is incremented automatically on every CS falling edge after the present channel is sampled. The analog inputs can be selected for an auto scan with register settings (see the auto-scan sequencing control registers). The device automatically scans only the selected analog inputs in ascending order.
The maximum overall throughput for the ADS8688AT is specified at 500 kSPS across all channels. The per channel throughput is dependent on the number of channels selected in the multiplexer scanning sequence. For example, the throughput per channel is equal to 250 kSPS if only two channels are selected, but is equal to 125 kSPS per channel if four channels are selected, and so forth.
See Table 7 for command register settings to switch between the auto-scan mode and manual mode for individual analog channels.