MAX31911_13 Datasheet, PDF (1/15 Pages) Maxim Integrated Products – Industrial, Octal, Digital Input Translator/Serializer

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MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
General Description
The MAX31911 industrial interface serializer translates,
conditions, and serializes the 24V digital output of sen-
sors and switches used in industrial, process, and build-
ing automation to 5V CMOS-compatible signals required
by microcontrollers. It provides the front-end interface cir-
cuit of a programmable logic controller (PLC) digital input
module. The device features integrated current limiting,
lowpass filtering, and channel serialization. Input current
limiting allows a significant reduction in power consumed
from the field voltage supply as compared to traditional
discrete resistor-divider implementations. Selectable on-
chip lowpass filters allow flexible debouncing and filter-
ing of sensor outputs based on the application. On-chip
serialization allows a drastic reduction in the number of
optocouplers used for isolation. The device serializer is
stackable so that any number of input channels can be
serialized and output through only one SPI-compatible
port. This reduces the number of optocouplers needed
to only three, regardless of the number of input channels.
For enhanced robustness with respect to high-frequency
noise and fast electrical transients, a multibit CRC code
is generated and transmitted through the SPI port for
each 8 bits of data. The on-chip 5V voltage regulator can
be used to power external optocouplers, digital isolators,
or other external 5V circuitry.
For ultra-low-power applications, Maxim Integrated offers
a pin-compatible version of this device, the MAX31910.
The MAX31910 uses patent-pending circuit techniques to
achieve further reduction of power beyond what is pos-
sible by input current limiting alone.
The future generation version of the MAX31910 and
MAX31911 will include energy-less LED drivers while
maintaining pin compatibility.
Ordering Information appears at end of data sheet.
Features
S Eight High-Voltage Input Channels (36V max)
S Configurable for IEC 61131-2 Input Types 1, 2, 3
S Wide Operating Supply Range of 7V to 36V
S Optional Configuration Allows 5V Supply
S Selectable Input Filtering and Debouncing from
0ms to 3ms
S Configurable Input Current Limiting from 0.5mA
to 6mA
S High HBM ESD Immunity on All Field Input Pins
S On-Chip 8-to-1 Serialization with SPI Interface
S On-Chip 5V Regulator
S Overtemperature Indicator
S On-Chip 24V Field Supply Voltage Monitor
S Low Quiescent Current and Power Dissipation
S Multibit CRC Code Generation and
Transmission for Error Detection and More
Reliable Data Transmission to an External Micro
Applications
Digital Input Modules for PLCs
Industrial, Building, and Process Automation
Motor Control
Block Diagram
24V
VCC24V
SENSORS
RIREF
RT1
IN1
RT8
IN8
GND
5V REGULATOR
VREF
SUPPLY
MONITOR
TEMP
MONITOR
MAX31911
OR
CURRENT
LIMITER
VOLTAGE
VREF COMPARATOR
LP
FILTER
INPUT CHANNEL 0
CRC GEN.
SERIALIZER
5V
5VOUT
FAULTB
DB0
DB1
SIN
MODESEL
CLK
CS
µCONTROLLER
OR
ISOLATION
INPUT CHANNEL 7
SOUT
For related parts and recommended products to use with this part, refer to www.maximintegrated.com/MAX31911.related.
For pricing, delivery, and ordering information, please contact Maxim Direct at
1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
19-6441; Rev 2; 10/13