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 420mA 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 PackageApplication·Industrial Process Control
·Automated Test Equipment
·Data-Acquisition Systems
·Digital Panel Meters
·Digital Voltmeters
·Digital MultimetersPinout
Specifications(With reference to GND, unless otherwise specified.)
AVDD, DVDD ............................................................-0.3V to +6.0V
AIN+, AIN-, REF+, REF-.............................VNEGV to (AVDD + 0.3V)
REG_FORCE, CMP, DAC_VDD, DACVOUT,
CONV_IN, 4-20OUT....................................-0.3V to (AVDD + 0.3V)
EN_BPM, EN_I, REFSELE, DACDATA_SEL,
CLK, EOC, CS_DAC, SCLK, DIN
DOUT........................................................-0.3V to (DVDD + 0.3V)
NEGV ........................................................-2.6V to (AVDD + 0.3V)
LED_EN.....................................................-0.3V to (DVDD + 0.3V)
SET............................................................-0.3V to (AVDD + 0.3V)
REG_AMP, REG_VDD ..............................................-0.3V to +6.0V
LEDG......................................................................-0.3V to +0.3V
GND_DAC ..............................................................-0.3V to +0.3V
GND_V/I.................................................................-0.3V to +0.3V
SEG_ to LEDG..........................................-0.3V to (VLEDV + 0.3V)
DIG_ to LEDG...........................................-0.3V to (VLEDV + 0.3V)
LOWBATT .................................................-0.3V to (AVDD + 0.3V)
REF_DAC ..................................................-0.3V to (AVDD + 0.3V)
DACVOUT.................................................-0.3V to (AVDD + 0.3V)
DIG_ Sink Current .............................................................300mA
DIG_ Source Current...........................................................50mA
SEG_ Sink Current ..............................................................50mA
SEG_ Source Current..........................................................50mA
Maximum Current Input into Any Other Pin ........................50mA
Continuous Power Dissipation (TA = +70°C)
48-Pin TQFP (derate 22.7mW/°C above +70°C)......1818.2mW
Operating Temperature Range ........................-40°C to +85°C
Storage Temperature Range .........................-60°C to +150°C
Lead Temperature (soldering, 10s) ...............................+300°CDescriptionThe MAX1366/MAX1368 low-power, 4.5- and 3.5-digit, panel meters feature an integrated sigma-delta analogto- digital converter (ADC), LED display drivers, voltage digital-to-analog converter (DAC), and a 420mA (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 420mA (or 0 to 16mA) current-loop output.
In normal operation, the 0 to 16mA/420mA currentloop 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. Onchip 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.
MAX1368 Data Sheet
