MAX1366 Microcontroller interface, 4.5-/3.5-Digit panel meter 4-20mA output
description
MAX1366/MAX1368 low-power, 4.5 and 3.5-bit panel meters, featuring an integrated sigma-delta analog-to-digital converter (ADC), LED display driver, voltage digital-to-analog converter (DAC), and a 4-20mA (or 0 to 16 mA), current driver.
The analog input voltage range of MAX1366/MAX1368 is ±2V or ±200mV programmable. MAX1368-driven 3.5-bit (±1999 count) display and MAX1366-driven 4.5-bit (±19,999 count) display. The ADC output directly drives the LED display, as well as the voltage DAC, which in turn drives 4-20mA (or 0 to 16 mA) with a current loop output.
In normal operation, the 2V or ±200mV analog input drives remote panel table displays, data loggers, and other industrial controllers at 0 to 16mA/4-20mA current loop outputs± or 200mV analog inputs. For added flexibility, the MAX1366/MAX1368 allows direct access to the ADC results, the V/I converter input of the DAC output.
Sigma-ΔADC does not require external precision integral capacitors, auto-zeroing capacitors, crystal oscillators, charge pumps, or other requirements of the dual-slope ADC panel meter circuit commonly used in other circuits. Analog inputs and reference buffers on the chip, allowing direct interface with high-impedance sources. Excellent common-mode rejection and digital filtering provide greater than 100dB of simultaneous 50Hz and 60Hz supply noise rejection. Other features include data hold, peak detection, and over/under range detection.
MAX1366/MAX1368 requires a 2.7V to 5.25V supply at 5.75VV 4.75V/my supply and power on a 7V to 30V loop. They are available in a space-saving (7mm x 7mm), 48-pin TQFP package and operate over an extended (-40°C to +85°C) temperature range.
Key features:
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Microcontroller (μC) interface, digital panel table
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20-position Sigma-Δ type ADC
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4.5-bit resolution (± 19,999 counts, MAX1366)
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3.5-bit resolution (±1999 count, MAX1368)
- No integrated/auto-zeroing capacitors
- 100MΩ input impedance
- ± input range of 200mV or ±2.000V
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LED display
- Common cathode 7-segment LED driver
- Programmable LED Current (0 to 20mA)
- 2.5 Hz refresh rate
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Output DAC and current driver
- ± 15-bit DAC, 14-bit linear V/I conversion
- Selectable from 0 to 16 mA or 4-20mA current output
- Unipolar/bipolar mode
- ± 50μA zero scale, ±40ppmFS/°C (typical)
- ± 0.5% gain error ± 25ppmFS/°C (typical)
- Separate 7V to 30V supply current loop output
- Power supply from 2.7V to 5.25V ADC/DAC
- 4.75V to 5.25VV/I converter supply
- 2.048V internal reference or external reference
- SPI™-/QSPI™-/MICROWIRE™ compatible serial interface
- 48-pin, 7mm x 7mm TQFP package
Applications/Uses:
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Automated Test Equipment (ATE)
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Data acquisition system
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Digital multimeter
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Digital panel table
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Digital voltmeter
- Industrial process control