MAX1366Interface of microcontroller, 4.5-/3.5-Digit panel meter 4-20mA output
description
The MAX1366/MAX1368 low-power, 4.5- and 3.5-bit panel meters feature an integrated sigma-delta analog-to-digital converter (ADC), LED display driver, voltage digital-to-analog converter (DAC), and 4-20mA (or 0 to 16 mA) current driver.
The MAX1366/MAX1368 have a programmable analog input voltage range of ±2V or ±200mV. The MAX1368 drives a 3.5-bit (±1999 count) display and the MAX1366 drives a 4.5-bit (±19,999 count) display. The ADC output drives the LED display directly, as well as the voltage DAC, which in turn, drives a 4-20mA (or 0 to 16 mA), current loop output.
In normal operation, the 0 to 16mA/4-20mA current loop output ±2V or ±200mV analog inputs drive remote panel meter displays, data loggers, and other industrial controllers. For added flexibility, the MAX1366/MAX1368 allow direct access to the ADC results and the V/I converter input of the DAC output.
Σ-ΔADCs do not require external precision integrating capacitors, autozero capacitors, crystal oscillators, charge pumps, or other dual-slope ADC panel meter circuits commonly used in circuits. On-chip analog inputs and reference buffers allow direct interfacing with high impedance signal sources. Excellent common-mode rejection and digital filtering provide greater than 100dB of simultaneous 50Hz and 60Hz power supply noise rejection. Other features include data hold, peak detection, and overrange/underrange detection.
The MAX1366/MAX1368 require a 2.7V to 5.25V supply at 4.75V/me at 5.75VV and a 7V to 30V loop. 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.
Key features
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Microcontroller (μC) interface, digital panel table
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20-bit Σ-Δ ADC
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4.5-Bit Resolution (±19,999 Count, MAX1366)
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3.5-bit resolution (± 1999 count, MAX1368)
- There is no integrated/auto-zero capacitor
- 100MΩ input impedance
- ± 200mV or ±2.000V input range
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LED display
- Common cathode 7-segment LED driver
- Programmable LED Current (0 to 20mA)
- 2.5 Hz renewal rate
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Output DAC and current driver
- ± 15-bit DAC, 14-bit linear V/I conversion
- A selectable 0 to 16 mA or 4-20mA current output is available
- Unipolar/bipolar mode
- ±50μA Zero Scale, ±40ppmFS/°C (typical)
- ± 0.5% Gain Error ±25ppmFS/°C (typical)
- Separate 7V to 30V supply current loop output
- 2.7V to 5.25V ADC/DAC power supply
- 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
Application/Purpose
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Automatic 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