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Microcontroller-Interface, 4.5-/3.5-Digit Panel Meters with 4-20mA Output

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • Microcontroller (µC)-Interface, Digital Panel Meter
    • 20-Bit Sigma-Delta ADC
      • 4.5-Digit Resolution (±19,999 Count, MAX1366)
      • 3.5-Digit Resolution (±1999 Count, MAX1368)
    • No Integrating/Autozeroing Capacitors
    • 100MΩ Input Impedance
    • ±200mV or ±2.000V Input Range
  • LED Display
    • Common-Cathode 7-Segment LED Driver
    • Programmable LED Current (0 to 20mA)
    • 2.5Hz Update Rate
  • Output DAC and Current Driver
    • ±15-Bit DAC with 14-Bit Linear V/I Converter
    • Selectable 0 to 16mA or 4–20mA Current Output
    • Unipolar/Bipolar Modes
    • ±50µA Zero Scale, ±40ppmFS/°C (typ)
    • ±0.5% Gain Error, ±25ppmFS/°C (typ)
    • Separate 7V to 30V Supply for Current-Loop Output
  • 2.7V to 5.25V ADC/DAC Supply
  • 4.75V to 5.25V V/I Converter Supply
  • Internal 2.048V Reference or External Reference
  • SPI™-/QSPI™-/MICROWIRE™-Compatible Serial Interface
  • 48-Pin, 7mm x 7mm TQFP Package

Applications/Uses

  • Automated Test Equipment (ATE)
  • Data Acquisition Systems
  • Digital Multimeters
  • Digital Panel Meters
  • Digital Voltmeters
  • Industrial Process Control

Description

The MAX1366/MAX1368 low-power, 4.5- and 3.5-digit, panel meters feature an integrated sigma-delta analog-to-digital converter (ADC), LED display drivers, voltage digital-to-analog converter (DAC), and a 4–20mA (or 0 to 16mA) current driver.

The MAX1366/MAX1368's analog input voltage range is programmable to either ±2V or ±200mV. The MAX1368 drives a 3.5-digit (±1999 count) display and the MAX1366 drives a 4.5-digit (±19,999 count) display. The ADC output directly drives the LED display as well as the voltage DAC, which, in turn, drives the 4–20mA (or 0 to 16mA) current-loop output.

In normal operation, the 0 to 16mA/4–20mA current-loop output follows the ±2V or ±200mV analog input to drive remote panel-meter displays, data loggers, and other industrial controllers. For added flexibility, the MAX1366/MAX1368 allow direct access to the ADC result, DAC output, and the V/I converter input.

The sigma-delta ADC does not require external precision integrating capacitors, autozero capacitors, crystal oscillators, charge pumps, or other circuitry commonly required in dual-slope ADC panel-meter circuits. On-chip analog input and reference buffers allow direct interface with high-impedance signal sources. Excellent common-mode rejection and digital filtering provides greater than 100dB rejection of simultaneous 50Hz and 60Hz line noise. Other features include data hold and peak detection and overrange/underrange detection.

The MAX1366/MAX1368 require a 2.7V to 5.25V supply, a 4.75V to 5.75V V/I supply, and a 7V to 30V loop supply. They are available in a space-saving (7mm x 7mm), 48-pin TQFP package and operate over the extended (-40°C to +85°C) temperature range.

Simplified Block Diagram

MAX1366, MAX1368: Typical Operating Circuit MAX1366, MAX1368: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .