A circuit diagram for channel monitoring using AD5380 multi-channel DAC

In multi-channel DAC systems, being able to monitor all outputs from a single point is very beneficial for troubleshooting and diagnostic analysis. The circuit described in this article utilizes a single-channel SAR type ADC to implement output channel monitoring of a multi-channel DAC.

The AD5380 is a complete 40-channel, 14-bit DAC powered by a single power supply. All 40 channels feature a rail-to-rail on-chip output amplifier. The AD5380 has a built-in channel monitoring function, which is implemented by a multiplexer addressed through the serial interface. Any channel output can be routed to the monitoring output (MON_OUT) pin for monitoring with an external ADC. For any channel to be routed to MON_OUT, the channel monitoring function must first be enabled in the control register. The microcontroller or processor can select the output channel to be monitored through its serial output port and then read the ADC converted data through its serial input port.

The circuit diagram shown below utilizes the internal multiplexer of the 40-channel, 14-bit DACAD5380 to allow all 40 output channels to be individually routed to a single output (MON_OUT) pin, which is then routed through an external ADC (AD7476). monitor. This approach utilizes far less circuitry than would be required to monitor each channel individually.