MAX14001AAP+ Isolated ADC

By Maxim Integrated 553

MAX14001AAP+ Isolated ADC

Maxim's MAX14001AAP+ is an isolated, single-channel analog-to-digital converter (ADC). This ADC has programmable voltage comparators and inrush current control optimized for configurable binary input applications. There is 3.75 kVRMS of integrated isolation provided between the binary input side (field-side) and the comparator output/SPI-side (logic-side) of the ICs. An integrated, isolated, DC-DC converter powers all field-side circuitry, and this allows running field-side diagnostics even when no input signal is present.

This device 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 device where the magnitude of the input voltage is compared to programmable thresholds. Response time of the comparator to an input change is less than 150 μs with filtering disabled. With filtering enabled, the comparator uses the moving average of the last two, four, or eight ADC readings. Both filtered and unfiltered ADC readings are available through the 5 MHz SPI port.

MAX14001AAP+ controls the current of a binary input through an external, high-voltage FET. This current cleans relay contacts and attenuates input noise. An inrush comparator monitoring the ADC reading triggers the inrush current or wetting pulse. The inrush trigger threshold, current magnitude, and current duration are all programmable in the MAX14001AAP+. When the high-voltage FET is not providing inrush current, it switches to bias mode. Bias mode places a small current load on the binary input to attenuate capacitively coupled noise. The level of bias current is programmable between 50 μA and 3.75 mA. This allows optimization of the tradeoff between noise attenuation and power dissipation.

Features
  • Enables robust detection of binary inputs
    • Programmable input bias current rejects line noise
    • 3.75 kVRMS of isolation for 60 seconds
    • 5.5 mm of creepage and clearance
    • Group II CTI package material
  • Provides unparalleled flexibility
    • Programmable upper and lower input thresholds
    • Programmable inrush current activation threshold, magnitude, and duration
    • Daisy-chainable SPI interface
  • Reduces BOM and board space through high integration
    • 10-bit, 10 ksps ADC
    • Binary threshold comparators
    • Control circuit for driving a depletion mode FET
    • Isolation for both data and DC-DC supply
    • 20-SSOP package
  • Increases equipment "up time" and simplifies system maintenance
    • Enables field-side diagnostics
    • Automatic self-diagnostics

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