Overview

The MAX22530–MAX22532 are galvanically isolated, 4-channel, multiplexed, 12-bit, analog-to-digital converters (ADC) in the MAXSafe™ family product line. An integrated, isolated, DC-DC converter powers all field-side circuitry, and this allows field-side diagnostics even when no input signal is present.

The MAX22530–MAX22532 family continually digitizes the input voltage on the field-side of an isolation barrier and transmits the data across the isolation barrier to the logic-side of the devices where the magnitude of the input voltage is compared to programmable thresholds. The 12-bit ADC core has a sample rate of 20ksps (typ) per-channel. ADC data is available through the SPI interface either directly or filtered. Filtering averages the most recent 4 readings depending on the setting.

Each input has a comparator with programmable high and low thresholds, and an interrupt is asserted when any input crosses its programmed level based on the mode setting. The comparator output pin (COUT_) is high when the input voltage is above the upper threshold and low when it is below the lower threshold in digital input mode. Typical response time of the comparator to an input change is less than 75µs with filtering disabled. With filtering enabled, the comparator uses the moving average of the last 4 ADC readings.

The MAX22530 in a 16-pin wide SOIC package provides 8mm of creepage and clearance, and 5kVRMS isolation. The MAX22531 in a 20-pin SSOP package and the MAX22532 in a 28-pin SSOP package, both provide 5.5mm of creepage and clearance, and 3.5kVRMS isolation. All package material has a minimum comparative tracking index (CTI) of 400, which gives it a group II rating in creepage tables.

All devices are rated for operation at ambient temperatures between -40°C to +125°C.