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.
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
19-6441; Rev 2; 10/13
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part, refer to www.maximintegrated.com/MAX31911.related.
EVALUATION KIT AVAILABLE
SOUT
CS
MODESEL
SIN
DB1
DB0
FAULTB
5VOUT
VCC24V
RIREF
GND
RT1
IN1
RT8
IN8
VREF
INPUT CHANNEL 0
VREF
SENSORS
24V
OR
CRC GEN.
µCONTROLLER
OR
ISOLATION
5V
5V REGULATOR
INPUT CHANNEL 7
SUPPLY
MONITOR
TEMP
MONITOR
CURRENT
LIMITER
LP
FILTER
CLK
VOLTAGE
COMPARATOR
SERIALIZER
MAX31911
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.
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
2Maxim Integrated
(Voltages relative to GND.)
Voltage Range on VCC24V ............................. -0.3V to +45V
Voltage Range on IN1–IN8 ............................ -0.3V to +45V
Voltage Range on IN1–IN8
(through 2.2kω resistors) ............................. -45V to +45V
Voltage Range on DB0/DB1, CLK, SIN,
CS, MODESEL ............................... -0.3V to (VDD + 0.3V)
Continuous Power Dissipation (TA = +70NC)
TSSOP (derate 27mW/NC above +70NC) .......... 2162.2mW
Operating Temperature Range
Ambient Temperature .............................. -40NC to +125NC
Junction Temperature..............................-40NC to +150NC
Storage Temperature Range ......................-55NC to +125NC
Lead Temperature (soldering, 10s) .........................+300NC
Soldering Temperature (reflow) ...............................+260NC
TSSOP
Junction-to-Ambient Thermal Resistance (qJA) ..........37°C/W
Junction-to-Case Thermal Resistance (qJC) .................2°C/W
ABSOLUTE MAXIMUM RATINGS
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
RECOMMENDED OPERATING CONDITIONS (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Field Supply Voltage VCC24V 7 36 V
Field Inputs Voltage VINn (Note 3) -0.3 36 V
Logic Inputs Voltage VLOGIC 0 5.5 V
Current-Limit Setting Resistor RREF 15 kI
Field Input Data Rate fIN (Note 4) 200 kHz
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
3Maxim Integrated
DC ELECTRICAL CHARACTERISTICS
(VCC24V = 7V to 36V, TJ = -40NC to +150NC, unless otherwise noted.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Field-Supply Current ICC24V IN1–IN8 = 24V, 5VOUT = open,
RT1–RT8 = GND, all logic inputs open 1.4 2.0 mA
Field-Supply UVLO Off/On VONUVLO 9 10 V
Field-Supply UVLO On/Off VOFFUVLO 7 8 V
Field Input Threshold High-
to-Low VIN-(INF) 2.2kI external series resistor 6 7.5 V
Field Input Threshold Low-to-
High VIN+(INF) 2.2kI external series resistor 8.5 10 V
Field Input Hysteresis VHYS(INF) 2.2kI external series resistor 1 V
Input Threshold High-to-Low
(at IC pin) VTH-(INP) 2 2.5 V
Input Threshold Low-to-High
(at IC pin) VTH+(INP) 3.5 4 V
Input Threshold Hysteresis
(at IC pin) VHYS(INP) 1 V
Field Input Pin Resistance RINP 0.8 kI
Field Input Current Limit IINLIM RREF = 15kI, VCC24V = 18V to 30V
(Note 5) 2.2 2.4 2.6 mA
Filter Time Constant tFILTER
DB1/DB0 = 0/0: no filtering 0
ms
DB1/DB0 = 0/1 0.008 0.025 0.038
DB1/DB0 = 1/0 0.25 0.75 1.1
DB1/DB0 = 1/1 1.0 3 4.5
Linear Regulator Output V5VOUT Max ILOAD = 50mA 4.75 5.0 5.25 V
Regulator Line Regulation dVREGLINE ILOAD = 50mA 10 20 mV
Regulator Load Regulation dVREGLOAD ILOAD = 1mA to 50mA 20 50 mV
Logic-Low Output Voltage VOL IOL = 4mA 0.4 1.0 V
Logic-High Output Voltage VOH IOH = -4mA 4.0 V
Logic-Input Trip Point VIH-IL 0.3 x
V5VOUT
0.5 x
V5VOUT
0.7 x
V5VOUT V
Logic-Input Leakage Current IIL -50 -30 -15 FA
Overtemperature Alarm TALRM 135 NC
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
4Maxim Integrated
Note 2: Limits are 100% production tested at TA = +25°C and/or TA = +125°C. Limits over the operating temperature range and
relevant supply voltage range are guaranteed by design and characterization. Typical values are not guaranteed.
Note 3: When using suggested external 2.2kω series resistors, limits of -3V to +36V apply.
Note 4: fIN refers to the maximum pulse frequency (1/fIN = shortest pulse width) that can be detected from the field sensors and
switches.
Note 5: External resistor RREF can be adjusted to set any desired current limit between 0.5mA and 6mA.
Note 6: See Figure 8.
Note 7: See Figure 5.
Note 8: See Figure 7.
Note 9: See Figure 6.
Note 10: This is the maximum bit transfer rate through the serializer interface.
AC ELECTRICAL CHARACTERISTICS: SPI INTERFACE
(VCC24V = 7V to 36V, TJ = -40NC to +150NC, unless otherwise noted.) (Note 2)
AC ELECTRICAL CHARACTERISTICS
(VCC24V = 7V to 36V, TJ = -40NC to +150NC, unless otherwise noted.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CLK Pulse Duration tCLKPW (Note 6) 20 ns
CS Pulse Duration tCSPW (Note 7) 20 ns
SIN to CLK Setup Time tSU1 (Note 8) 5 ns
SIN to CLK Hold Time tH1 (Note 8) 8 ns
CS to CLK Setup Time tSU2 (Note 9) 8 ns
CS to CLK Recovery Time tREC (Note 9) 12 ns
Clock Pulse Frequency fCLK (Notes 6, 10) DC 25 MHz
Propagation Delay, CLK to SOUT tP1 (Note 6) 20 ns
Propagation Delay, CS to SOUT tP2 (Note 7) 20 ns
Rise/Fall Time SOUT/FAULT tR/F (Note 6) 40 ns
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Field Input Pulse Width tPW No external capacitors on pins IN1-
IN8 1µs
ESD HBM, all pins ±2kV
HBM, IN1-IN8 with respect to GND ±15
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
5Maxim Integrated
Typical Operating Characteristics
(TA = +25°C, RREF = 15kω, unless otherwise noted.)
POWER-SUPPLY CURRENT
vs. VCC24V FIELD SUPPLY
MAX31911 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
1.35
1.40
1.45
1.50
1.55
1.60
1.30
5152
53
5
SUPPLY CURRENT vs. TEMPERATURE
MAX31911 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
6010
1.45
1.50
1.55
1.60
1.40
-40
CURRENT LIMIT vs. RREF
MAX31911 toc03
RREF (kI)
CURRENT LIMIT (mA)
40302010
5.5
0.5
1.5
2.5
3.5
4.5
0
INPUT CURRENT LIMIT
vs. TEMPERATURE
MAX31911 toc04
AMBIENT TEMPERATURE (°C)
CURRENT LIMIT (mA)
1106010
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
2.0
-40
VINn = 24V
INPUT CURRENT LIMIT
vs. FIELD INPUT VOLTAGE
MAX31911 toc05
FIELD INPUT VOLTAGE (V)
CURRENT LIMIT (mA)
352515
0.5
1.0
1.5
2.0
2.5
3.0
0
5
VINn = 24V
INPUT VOLTAGE HYSTERESIS
vs. TEMPERATURE
MAX31911 toc06
TEMPERATURE (°C)
THRESHOLD VOLTAGE (V)
1106010
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
2.0
-40
OFF-ON THRESHOLD
ON-OFF THRESHOLD
RIN = 0I
INPUT VOLTAGE HYSTERESIS
vs. TEMPERATURE
MAX31911 toc07
TEMPERATURE (°C)
THRESHOLD VOLTAGE (V)
1106010
7.2
7.4
7.6
7.8
7.0
8.2
8.4
8.6
8.8
9.0
7.0
-40
OFF-ON THRESHOLD
ON-OFF THRESHOLD
RIN = 2.2I
LDO LOAD REGULATION
MAX31911 toc08
5VOUT OUTPUT CURRENT (mA)
5VOUT VOLTAGE (V)
4.92
4.94
4.96
4.98
5.00
5.02
5.04
5.06
5.08
5.10
4.90
040 50302010
LDO LINE REGULATION
MAX31911 toc09
SUPPLY VOLTAGE (V)
5VOUT VOLTAGE (V)
4.92
4.94
4.96
4.98
5.00
5.02
5.04
5.06
5.08
5.10
4.90
6363126211611
I5VOUT = 5mA
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
6Maxim Integrated
Typical Operating Characteristics (continued)
(TA = +25°C, RREF = 15kω, unless otherwise noted.)
LDO LINE REGULATION
MAX31911 toc10
SUPPLY VOLTAGE (V)
5VOUT VOLTAGE (V)
4.92
4.94
4.96
4.98
5.00
5.02
5.04
5.06
5.08
5.10
4.90
6 363126211611
I5VOUT = 50mA
LDO OUTPUT VOLTAGE
vs. TEMPERATURE
MAX31911 toc12
AMBIENT TEMPERATURE (°C)
5VOUT VOLTAGE (V)
4.92
4.94
4.96
4.98
5.00
5.02
5.04
5.06
5.08
5.10
4.90
-40 1106010
I5VOUT = 0mA
LDO OUTPUT
vs. VCC24V FIELD SUPPLY
MAX31911 toc11
SUPPLY VOLTAGE (V)
5VOUT OTPUT VOLTAGE (V)
4.6
4.7
4.8
4.9
5.0
5.1
5.2
5.3
5.4
5.5
4.5
4342414
I5VOUT = 50mA
LDO OUTPUT VOLTAGE
vs. TEMPERATURE
MAX31911 toc13
AMBIENT TEMPERATURE (°C)
5VOUT VOLTAGE (V)
4.92
4.94
4.96
4.98
5.00
5.02
5.04
5.06
5.08
5.10
4.90
-40 1106010
I5VOUT = 5mA
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
7Maxim Integrated
Pin Description
Pin Configuration
PIN NAME FUNCTION
1, 2 DB0, DB1 Debounce (Filtering) Time Select Inputs
3, 5, 7, 9, 11, 18,
20, 22 IN1–IN8 Field Inputs
4, 6, 8, 10, 12,
17, 19, 21 RT1–RT8 Connect directly to GND. These pins are reserved for energy-less LED drives in future
versions of the device.
13 RIREF Current-Limiter Reference Resistor
14 VCC24V Field-Supply Voltage
15 5VOUT 5V Regulator Output
16 FAULT Active-Low Overtemperature or Undervoltage Alarm
23 SOUT Serial-Data Out
24 CS Active-Low Chip-Select Input
25 CLK Serial-Clock Input
26 MODESEL
Mode-Select Input
MODESEL = 1: Selects 8-bit shift register
MODESEL = 0: Selects 16-bit shift register
27 SIN Serial-Data Input
28 GND Field Ground
— EP Exposed Pad. Must be connected to the PCB ground plane.
TOP VIEW
MAX31911
254CLKRT1
263 MODESELIN1
272 SIN
DB1
281 +GNDDB0
227 IN8
IN3
236 SOUTRT2
218 RT8RT3
209 IN7IN4
1910 RT7RT4
1811 IN6IN5
1712 RT6RT5
1613 FAULTRIREF
245 CS
IN2
1514 5VOUTVCC24V
EP
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
8Maxim Integrated
Basic Application Circuit
Detailed Description
Input Current Clamp
The MAX31911 industrial interface serializer inputs
(IN1–IN8) sense the state (on vs. off) of field sen-
sors by monitoring both voltage and current flowing
through the sensor output. The current sinking through
these input pins rises linearly with input voltage until
the limit set by the current clamp is reached. Any volt-
age increase beyond this point does not increase the
input current any further.
The value of the current clamp is adjustable through
an external resistor connected between the RIREF pin
and GND. Pins RT1–RT8 must be connected directly
to GND to provide a return path for the input current.
The voltage and current at the IN1–IN8 input pins are
compared against internally set references to deter-
mine whether the sensor is on (logic 1) or off (logic
0). The trip points determining the on/off status of the
sensor satisfy the requirements of IEC 61131-2 Type
1 and 3 switches. The device can also be configured
to work as a Type 2 switch.
Glitch Filter
A digital glitch filter provides debouncing and filtering
of noisy sensor signals. The time constant of this filter
is programmable from 0ms to 3ms through the DB0
and DB1 pins. See Table 1 for debounce settings.
To provide the digital glitch filter, the device checks
that an input is stable for at least three clock cycles.
The duration of a clock cycle is 1/3 of the selected
debounce time. If the input is not stable for at least
three clock cycles, the input change is not sent to the
internal shift register.
GND
MODESEL
DB1
DB0
5VOUT
SIN
CLK
CS
SOUT
FAULT
CLK
CS
SOUT
FAULT
ISOLATION
JUMPERS TO
5VOUT
AND GND
C4
VDD_LOGIC
RREF
RINX
R1
24V
fIN1–8
RIREF
C1
IN1–8
RT1–8
VCC24V
MAX31911
NOTE: SEE FIGURE 1 FOR ADDITIONAL
COMPONENTS NEEDED FOR EMC.
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
9Maxim Integrated
Table 1. Debounce Settings
Reading Serial Data
The filtered outputs of the input comparators are
latched into a shift register at the falling edge of CS.
Clocking the CLK pin, while CS is held low, shifts the
latched data out of SOUT 1 bit at a time.
The internal data serializer comprises a 16-bit shift
register, containing 8 bits of data corresponding to
the eight field inputs, as well as an 8-bit status byte
containing supplementary status and CRC informa-
tion. The status byte contains 1 bit representing the
status of the field-supply voltage (UV), 1 bit represent-
ing the status of the internal temperature monitor (OT),
a 5-bit CRC code internally calculated and generated,
and a trailing 1 as a STOP bit.
The undervoltage (UV) bit is normally 0. If the supply
voltage falls below VOFFUVLO, the UV becomes a 1.
The UV bit returns to 0 once the supply voltage has
returned above VONUVLO.
The overtemperature (OT) bit is also normally 0. If the
junction temperature increases to above TALRM, the
OT bit becomes a 1. The bit returns to 0 once the junc-
tion temperature has returned below TALRM.
The CRC code can be used to check data integrity during
transfer from the device to an external microcontroller. In
applications where the integrity of data transferred is not
of concern, the CRC bits can be ignored. The CRC uses
the following polynomial:
P(x) = x5 + x4 + x2 + x0
The number of bits in the internal serializer can be
selected between 8 bits or 16 bits. The MODESEL
pin is used to configure the serializer as an 8-bit
(disabling the status byte) or 16-bit shift register.
In 8-bit mode, only the eight field input states are
transferred through the SPI port and the status byte is
ignored. Therefore, in multiple IC applications (input
channels greater than 8), if desired, only a single
status byte can be generated and transmitted for any
number of input channels.
The shift register contents are read only (no write
capability exists) through the SPI-compatible
interface.
For higher input counts than 8, multiple devices can
be cascaded. In this case, the SOUT pin of one device
should be connected to the SIN pin of the next device,
effectively cascading the internal shift registers. The
CLK and CS pins of all the devices should be con-
nected together in this configuration. See the Serial-
Port Operation section for more detailed information
on operating the SPI interface.
Temperature Monitoring
The internal junction temperature of the device is con-
stantly monitored. An alarm is raised, by asserting the
FAULT pin, if the temperature rises above TALRM. In addi-
tion to asserting FAULT, the device sets the OT bit to a 1.
Supply Voltage Monitoring
A supply voltage monitor circuit constantly monitors
the field-supply voltage. If this voltage falls below a
threshold (VOFFUVLO), an alarm is raised by asserting
the FAULT pin, indicating that the part is experiencing
a fault condition and the data in the serializer is not
to be trusted. In addition, the device sets the UV bit
to a 1. Once the field-supply voltage has recovered
and goes above VONUVLO, the FAULT pin is released,
indicating normal operation of the part.
DB1 DB0 BINARY VALUE DEBOUNCE TIME
0000
01125Fs
1 0 2 0.75ms
1 1 3 3ms
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
10Maxim Integrated
Table 2. Recommended Components
Applications Information
EMC Standards Compliance
The external components shown in Figure 1 allow the
device to operate in harsh industrial environments.
Components were chosen to assist in suppression
of voltage burst and surge transients, allowing the
system to meet or exceed international EMC require-
ments. Table 2 lists an example device for each com-
ponent in Figure 1. The system shown in Figure 1,
using the components shown in Table 2, is designed
to be robust against IEC fast transient burst, surge,
conducted RFI specifications, and ESD specifica-
tions (IEC 61000-4-4, -5, -6, and -2).
Figure 1. Typical EMC Protection Circuitry
COMPONENT DESCRIPTION REQUIRED/RECOMMENDED/OPTIONAL
C0 4.7nF, 2kV polypropylene capacitor Recommended
C1 10FF, 60V ceramic capacitor Required
C3 100nF, 10V ceramic capacitor Recommended
C4 4.7µF, 10V low ESR ceramic capacitor Required
C5 100nF, 100V ceramic capacitor Recommended
D0 36V fast zener diode (ZSMB36) Recommended
D1 General-purpose rectifier (IN4007)
Optional: For reverse polarity protection.
This diode alternatively can be placed in
series with the field supply (24V).
R1 150I, 1/3W MELF resistor Recommended
RINX 2.2kI, 1/4W MELF resistor Required
RREF 15kI, 1/8W resistor Required
GND
MODESEL
DB1
DB0
5VOUT
SIN
CLK
CS
SOUT
FAULT
CLK
CS
SOUT
FAULT
ISOLATION
JUMPERS TO
5VOUT
AND GND
C4C3
VDD_LOGIC
RREF
0V
RINX
fIN1–8
RIREF
IN1–8
RT1–8
D1
VCC24V
MAX31911
R1
24V
D0 C1
C0
C0 C5
EARTH
EARTH
Note: For higher EMC performance, a 1nF, 1000V capacitor can be added from nodes fIN1–IN8 to earth. Alternatively, a 270nF,
100V capacitor can be added from pins IN1–IN8 to device ground.
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
11Maxim Integrated
Serial-Port Operation
Serial output of the device functions in one of two
modes, depending on the MODESEL setting (Table 3).
With MODESEL = 0, the device output includes a 5-bit
CRC, an undervoltage alarm, and an overtemperature
alarm. See the Detailed Description for CRC, undervolt-
age, and overtemperature functional descriptions. With
MODESEL = 1, the device outputs only the state of the
IN1–IN8 inputs and omits the CRC, undervoltage alarm,
and overtemperature alarm.
Daisy-Chain Operation
For systems with more than eight sensor inputs, multiple
devices can be daisy-chained to allow access to all data
inputs through a single serial port. When using a daisy-
chain configuration, connect SOUT of one of the devices
to the SIN input of another upstream device. CS and SCK
of all devices in the chain should be connected together
in parallel (see Figure 2). In a daisy-chain configuration,
external components used to enhance EMC robustness
do not need to be duplicated for each device of a circuit
board. Figure 3 illustrates a 16-input application.
SPI Waveforms
The serial output of the device adheres to the SPI proto-
col, running with CPHA = 0 and CPOL = 0. Input states
on IN1–IN8 are latched in on the falling edge of CS. The
transfer of data out of the slave output, SOUT, starts
immediately when CS is asserted (i.e., MSB is output
onto SOUT independent of CLK). The remaining data bits
are shifted out on the falling edge of CLK. The data bits
are written to the output SOUT with MSB first. When CS
is high, SOUT is high impedance. The resultant timing is
shown in Figure 4. Note that all bits after IN1 are invalid
if 8-bit operation mode is selected with the MODESEL
input. Figure 5, Figure 6, Figure 7, and Figure 8 illustrate
SPI timing specifications.
Figure 2. Daisy-Chain Operation
Table 3. MODESEL Settings
MODESEL SETTING FUNCTIONALITY
0 16-bit output; [IN8–IN1][CRC (5 bit)][UV][OT][X]
1 8-bit output; [IN8–IN1]
MAX31911 MAX31911MAX31911
SIN
SOUT
SIN
SOUT
SIN
SOUT
TO µCONTROLLER
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
12Maxim Integrated
Figure 3. 16-Input Application Circuit
MODESEL
DB1
DB0
5VOUT
CLK
CS
SOUT
FAULT
CLK
CS
SOUT
FAULT
ISOLATION
SIN
JUMPERS TO
5VOUT
AND GND
JUMPERS TO
5VOUT
AND GND
C4C3
C4C3
VDD_LOGIC
RREF
0V
D1
RINX
fIN1–8
RIREF GND
IN1–8
RT1–8
VCC24V
MAX31911
R1
24V
D0 C1
C0
C0
GND
FAULT
SOUT
CS
CLK
SIN
MODESEL
DB1
DB0
5VOUT
RREF
RINX
fIN1–8
RIREF
C1
IN1–8
RT1–8
VCC24V
MAX31911
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
13Maxim Integrated
Figure 5. SPI Timing Diagram 1
Figure 6. SPI Timing Diagram 2
Figure 7. SPI Timing Diagram 3
Figure 8. SPI Timing Diagram 4
Figure 4. SPI Communication Example
SOUT
tCSPW tP2
CS CLK
SIN
tSU1 tH1
SIN VALID
CLK
tSU2 tREC
CS
tCLKPW
1/fCLK
tR/F
tR/F
tP1
SOUT
CLK
CLK
SOUT
IN8 –IN1
IN8 IN7 IN6 IN5 IN4 IN3 IN2 IN1 CRC4 CRC3 CRC2 CRC1 CRC0 UV OT RES
VALID
CS
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
14Maxim Integrated
Ordering Information
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Chip Information
PROCESS: S45JRS
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character,
but the drawing pertains to the package regardless of RoHS status.
PART TEMP RANGE PIN-
PACKAGE CARRIER
MAX31911AUI+ -40NC to +125NC28 TSSOP Bulk
MAX31911AUI+T -40NC to +125NC28 TSSOP Tape
and Reel
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
28 TSSOP-EP U28E+4 21-0108 90-0146
MAX31911
Industrial, Octal, Digital Input
Translator/Serializer
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and
max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000 15
© 2013 Maxim Integrated Products, Inc. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 8/12 Initial release —
1 9/12
Changed the supply voltage minimum from 10V to 7V; changed the current
limits in the EC table Note 5; added the CRC polynomial to the Reading
Serial Data section
1-4, 9
2 10/13
Updated Block Diagram, TOCs 4, 5, 8, 9, 10, Basic Application Circuit, Input
Current Clamp section, EMC Standards Compliance section, Table 2, Figure
1, Figure 3, and Figure 4
1, 5, 6, 8, 10, 12, 13
