MAX1365/MAX1367 low-power, 4.5- and 3.5-bit panel meters, features 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 MAX1365/MAX1367 is ±2V or ±200mV programmable. MAX1367-driven 3.5-bit (±1999 count) display and MAX1365-driven 4.5-bit (±19,999 count) display. The ADC output directly drives the LED display, as well as the DAC for voltage, which in turn drives 4-20mA (or 0 to 16 mA), the 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, MAX1365/MAX1367 allows direct access to 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.
MAX1365/MAX1367 requires a 2.7V to 5.25V supply, 4.75V to 5.75VV/my, 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.