EVALUATION KIT AVAILABLE
MAX31914
General Description
The MAX31914 translates and conditions the 24V digital output of sensors and switches used in industrial,
process, and building automation to 5V CMOS-compatible
signals required by microcontrollers. It provides the frontend interface circuit of a programmable logic controller
(PLC) digital input module.
The signal voltage translation is performed in conjunction
with input current limiting and lowpass filtering. Input
current limiting allows a significant reduction in power
consumed from the field-supply voltage, as compared
to traditional discrete resistor-divider implementations.
To achieve the lowest in-class power dissipation, the IC
uses patent-pending circuit techniques to achieve further
reduction of power dissipation beyond what is possible
by input current limiting alone. This special low-power
operating mode is automatically activated when on-chip
lowpass filtering is selected.
Selectable on-chip lowpass filters allow flexible debouncing
and filtering of sensor inputs based on the application.
When no filtering is selected, the IC is capable of detecting
pulses as short as 0.75µs at its field inputs.
All 8 input channels are translated to CMOS logic levels and
presented in parallel on the eight output pins for direct or
galvanically isolated interface with a controller ASIC or
micro.
The on-chip 5V voltage regulator can be used to power
external optocouplers, digital isolators, or other external
5V circuitry.
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Benefits and Features
●● Flexible Supply Options Enables Usage in 24V, 12V,
and 5V Supplied Systems
• 7V to 36V Wide Operating Field-Supply Range
• Device Can Be Optionally Powered from the LogicSide Using a 5V Supply
●● Low Power and Low Heat Dissipation
• Very Low Quiescent Current
• Extremely Accurate and Stable Input Current Limiters
• Special Ultra-Low-Power Operating Mode with
Switched Current Limiters
●● Configurability Enables a Wide Range of Standard
and Custom Applications
• Configurable Inputs for IEC 61131-2 Input Types 1,
2, and 3 or for Standard CMOS Logic Levels
• 0.5mA to 6mA Configurable Input Current Limiting
• Selectable Input Filtering and Debounce: 0, 25µs,
0.75ms, and 3ms Settings
●● High Integration Reduces BOM Count and Board
Space
• 8 High-Voltage Input Channels (36V Max)
• 8 CMOS Logic Outputs for High-Speed Simultaneous
Transfer of All Input States to the Controller
• On-Chip 5V Regulator
• On-Chip Overtemperature Indicator
• On-Chip Field-Supply Voltage Monitor
• High HBM ESD Immunity on all Field Input Pins
(15kV HBM)
For low-cost applications, Maxim Integrated offers a pin
compatible version of this device, the MAX31915, which
does not include the current-switching circuitry included
in the MAX31914.
Applications
●● Digital Input Modules for Programmable
Logic Controllers (PLCs)
●● Industrial Automation, Building Automation
●● Process Automation
19-7474; Rev 1; 4/15
Ordering Information appears at end of data sheet.
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Block Diagram
5V
24V
MAX31914
VCC24V
5V REGULATOR
5VOUT
VREF
SUPPLY MONITOR
SENSORS
UVFAULT
FAULT
TEMPERATURE
MONITOR
DB0
RIREF
RT1
IN1
SWITCHED
CURRENT LIMITER
LOWPASS
FILTER
VREF
GND
OP1
µCONTROLLER
OR
ISOLATION
VOLTAGE
COMP
VTSELECT
RT8
IN8
DB1
INPUT CHANNEL 0
INPUT CHANNEL 7
OP8
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Absolute Maximum Ratings
Voltage on VCC24V Relative to GND.....................-0.3V to +45V
Voltage on IN1–IN8 Relative to GND
through 2.2kΩ Resistors......................................-45V to +45V
Voltage on DB0/DB1,
VTSELECT Relative to GND...................... -0.3V to 6V + 0.3V
Ambient Temperature Range............................ -40°C to +125°C
Junction Temperature Range............................ -40°C to +150°C
Storage Temperature Range............................. -55°C to +125°C
Continuous Power Dissipation (TA = +70°C)
(derate 22.2mW/°C above +70°C)..........................1773.8mW
Soldering Temperature, Lead(Pb)-Free (reflow)................ 260°C
Lead Temperature (soldering, 10s).................................... 300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation 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)
TSSOP
Junction-to-Ambient Thermal Resistance (θJA)......45.10°C/W
Junction-to-Case Thermal Resistance (θJC)..................1°C/W
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.
Recommended Operating Conditions
PARAMETER
Field-Supply Voltage
SYMBOL
CONDITIONS
MIN
MAX
UNITS
36
V
-0.3
+36
V
-0.3
+5.5
V
VCC24V
Note 2
7
Field Inputs Voltage
VInn
Note 3
Logic Inputs Voltage
VLOGIC
Current-Limit Setting Resistor
RREF
TYP
VTSELECT = logic 1
15
VTSELECT = logic 0
150
kΩ
DC Electrical Characteristics
(TA = -40°C to +125°C, TJ ≤ 150°C, VCC24V = 7V to 36V, unless otherwise noted.)
PARAMETER
Field-Supply Curent
SYMBOL
ICC24V
Field-Supply Low Alarm Off-On
VONUVLO
Field-Supply Low Alarm On-Off
VOFFUVLO
CONDITIONS
MIN
IN1–IN8 = 24V, 5VOUT = open,
OP1–OP8 and all logic inputs = open
7
TYP
MAX
UNITS
1.6
2.3
mA
8
9
V
10
V
Field Input Threshold, High to Low
VIN1-(INF)
2.2kΩ external series resistor,
VTSELECT = logic 1, RREF = 15kΩ
Field Input Threshold, Low to High
(Note 4)
VIN1+(INF)
2.2kΩ external series resistor,
VTSELECT = logic 1, RREF = 15kΩ
9.4
Field Input Hysterisis (Note 4)
VHYS1(INF)
2.2kΩ external series resistor,
VTSELECT = logic 1, RREF = 15kΩ
1
V
VIN0-(INF)
2.2kΩ external series resistor,
VTSELECT = logic 0, RREF = 150kΩ
1.7
V
Field Input Threshold, High to Low
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7
1.5
8.4
V
10.5
V
Maxim Integrated │ 3
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
DC Electrical Characteristics (continued)
(TA = -40°C to +125°C, TJ ≤ 150°C, VCC24V = 7V to 36V, unless otherwise noted.)
PARAMETER
SYMBOL
Field Input Threshold, Low to High
VIN0+(INF)
Field Input Hysterisis (Note 4)
CONDITIONS
TYP
MAX
UNITS
2.2kΩ external series resistor,
VTSELECT = logic 0, RREF = 150kΩ
2.2
3.5
V
VHYS0(INF)
2.2kΩ external series resistor,
VTSELECT = logic 0, RREF = 150kΩ
0.5
V
Input Threshold, High to Low
(at IC Pin)
VTH1-(INP)
VTSELECT = logic 1, RREF = 15kΩ
3.4
V
Input Threshold, Low to High
(at IC Pin) (Note 4)
VTH1+(INP)
VTSELECT = logic 1, RREF = 15kΩ
4.4
Input Threshold Hysteresis
(at IC Pin) (Note 4)
VHYS1(INP)
VTSELECT = logic 1, RREF = 15kΩ
1
V
Input Threshold, High to Low
(at IC Pin)
VTH0-(INP)
VTSELECT = logic 0, RREF = 150kΩ
1.7
V
Input Threshold, Low to High
(at IC Pin)
VTH0+(INP)
VTSELECT = logic 0, RREF = 150kΩ
2.2
Input Threshold Hysteresis
(at IC Pin)
VHYS0(INP)
VTSELECT = logic 0, RREF = 150kΩ
0.5
V
Field Pin Input Resistance
RINP
0.8
kΩ
Field Input Curent Limit
IINLIM
RREF = 15 kΩ (Note 5),
VTSELECT = logic 1
MIN
3
1.5
2.26
DB1/DB0 = 0/0: no filtering
Filter Time Constant
Linear Regulator Output
tFILTER
V5VOUT
0.038
DB1/DB0 = 1/0
0.25
0.75
1.1
DB1/DB0 = 1/1
1.0
3
4.5
Max IlLOAD = 50mA
4.75
5.0
5.25
dVREGLOAD ILOAD = 1mA to 50mA
ILOAD = 50mA
Logic-Low Output Voltage
VOL
IOL = 4mA
Logic-High Output Voltage
VOH
IOH = -4mA
4.0
All inputs have internal pullups
-50
LED On-State Current
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TALRM
RREF = 15kΩ, DB0, DB1 = 0, 0
(current switching disabled)
V
V
mA
0
0.025
Regulator Load Regulation
IIL
2.72
0.008
dVREGLINE
Overtemperature Alarm
3.5
DB1/DB0 = 0/1
Regulator Line Regulation
Logic Input Leakage Curent
2.45
5
ms
V
10
mV
20
mV
0.4
1.0
V
V
-30
-15
µA
135
°C
2.2
mA
Maxim Integrated │ 4
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
AC Electrical Characteristics
(TA = -40°C to +125°C, TJ ≤ 150°C, VCC24V = 7V to 36V, unless otherwise noted.)
PARAMETER
Input Data Rate
Input Pulse Width
Interchannel Propagation-Delay
Mismatch (Interchannel Jitter)
Propagation Delay
Output Rise/Fall Times
(on OPn Pins)
ESD
SYMBOL
CONDITIONS
fIN
DB0, DB1 = 0, 0 (filters disabled)
PWIN
DB0, DB1 = 0, 0 (filters disabled)
ϕint
tPROP
tR/F
MIN
TYP
MAX
UNITS
1.3
Mbps
0.75
µs
(Note 6)
12V input applied on the field side
through external 2.2kΩ resistors,
RREF set to 15k, VTSEL = 1
(Notes 7, 8)
300
Internally slew limited
(with CLOAD = 0–50pF)
25
HBM, all pins
±2
HBM, IN1–IN8 with respect to GND
±15
25
ns
700
ns
ns
kV
Note 2: If a 24V supply is not available, the device can be powered through 5VOUT. In this mode of operation, the VCC24V
supply must be left unconnected. All other specifications remain identical. The field-supply alarms are asserted indicating
the absence of the 24V supply in this mode of operation.
Note 3: When using suggested external 2.2kΩ series resistors, limits of -36V to +36V apply.
Note 4: When input current switching is enabled (DB0/DB1 = 0), there is no input threshold hysteresis. In this case, the input
threshold for both falling and rising signals is the high to low threshold.
Note 5: External resistor RREF can be adjusted to set any desired current limit between 0.5mA and 6mA.
Note 6: INn-to-OPn propagation delay difference between two channels on the same IC.
Note 7: Propagation delay from field input (INn) to CMOS output (OPn). Tested with a 6.5V pulse applied directly to the device INn
pins. Propagation delay is measured between the 50% transitions of the rising and falling edges.
Note 8: The propagation delay limit is 1ms maximum when VTSEL = 0.
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Maxim Integrated │ 5
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Typical Operating Characteristics
(TA = +25°C, RREF = 15kω, unless otherwise noted.)
1.5
1.0
4
14
24
1.5
1.0
1.5
10
-40
60
0.5
110
0
20
30
50
40
INPUT-VOLTAGE HYSTERESIS
vs. TEMPERATURE
2.4
2.3
2.2
2.0
1.5
1.0
0.5
VCC24V = 24V
2.1
-40
10
60
15
5
110
INPUT-VOLTAGE HYSTERESIS
vs. TEMPERATURE
ON-OFF THRESHOLD
7.6
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ON-OFF THRESHOLD
3.0
-40
10
110
60
110
TEMPERATURE (°C)
LDO LINE REGULATION
5.10
MAX31914 toc08
5.08
5.06
5.02
5.00
4.98
4.96
I5VOUT = 5mA
5.08
5.06
5VOUT VOLTAGE (V)
5.04
5.04
5.02
5.00
4.98
4.96
4.94
4.94
4.92
4.92
4.90
TEMPERATURE (°C)
3.2
LDO LOAD REGULATION
5VOUT VOLTAGE (V)
OFF-ON THRESHOLD
8.8
60
3.6
3.4
35
5.10
MAX31914 toc07
RIN = 2.2I
9.6
9.4
10
3.8
FIELD-INPUT VOLTAGE (V)
TEMPERATURE (°C)
9.2
9.0
25
OFF-ON THRESHOLD
4.0
2.8
2.6
0
2.0
RIN = 0I
4.6
4.4
4.2
MAX31914 toc09
CURRENT INPUT (mA)
2.5
5.0
4.8
INPUT-VOLTAGE HYSTERESIS (V)
MAX31914 toc04
3.0
MAX31914 toc06
INPUT CURRENT LIMIT
vs. FIELD-INPUT VOLTAGE
2.5
-40
10
INPUT CURRENT LIMIT
vs. TEMPERATURE
2.6
8.0
7.8
2.5
RREF (kI)
2.7
8.6
8.4
8.2
3.5
TEMPERATURE (°C)
2.8
10.0
9.8
4.5
SUPPLY VOLTAGE (V)
VINn = 24V
2.9
CURRENT INPUT (mA)
2.0
0
34
3.0
INPUT-VOLTAGE HYSTERESIS
5.5
0.5
0.5
0
MAX31914 toc02
2.5
CURRENT LIMIT (mA)
2.0
CURRENT LIMIT vs. RREF
MAX31914 toc05
SUPPLY CURRENT (mA)
2.5
3.0
SUPPLY CURRENT (mA)
MAX31914 toc01
3.0
SUPPLY CURRENT
vs. TEMPERATURE
MAX31914 toc03
SUPPLY CURRENT
vs. VCC24V FIELD SUPPLY
4.90
0
10
20
30
40
5VOUT OUTPUT CURRENT (mA)
50
6
11
16
21
26
31
36
SUPPLY VOLTAGE (V)
Maxim Integrated │ 6
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Typical Operating Characteristics (continued)
(TA = +25°C, RREF = 15kω, unless otherwise noted.)
LDO OUTPUT
vs. VCC24V FIELD SUPPLY
5.02
5.00
4.98
4.96
5.2
5.1
5.0
4.9
4.8
5.06
5.04
5.02
5.00
4.98
4.96
4.94
4.92
4.6
4.92
4.90
4.5
11
16
21
26
31
0.35
0.30
0.25
0.20
0.15
0.05
0
4.90
60
110
AMBIENT TEMPERATURE (°C)
PROPAGATION DELAY vs. TEMPERATURE
(FIELDPROPAGATION
INPUT VOLTAGE
= 18V)
DELAY
vs. TEMPERATURE
0
2
300
250
200
150
-40
MAX31914 toc16
MAX31914 toc16
PROPAGATION DELAY (ns)
350
450
FALL TIME
400
FALL TIME
350
300
250
RISE TIME
200
150
100
RISE TIME
10
60
TEMPERATURE (°C)
-40
10
110
60
TEMPERATURE (°C)
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110
MAX31914 toc15
FALL TIME
30
25
RISE TIME
20
15
4
-40
10
FIELD INPUT VOLTAGE (V)
60
110
TEMPERATURE (°C)
(FIELD INPUT VOLTAGE = 18V)
VTSELECT = 1
15kΩ
RREF =600
VTSELECT = 1
550
RREF = 15kΩ
500
35
600
PROPAGATION DELAY vs. TEMPERATURE
(FIELD INPUT VOLTAGE = 4.5V)
MAX31914 toc17
0.10
40
OUTPUT RISE/FALL TIME (ns)
CURRENT LIMIT (mA)
0.40
4.92
10
VTSELECT = 0
RREF = 100kΩ
0.45
4.94
-40
MAX31914 toc14
0.50
MAX31914 toc13
4.96
400
110
OUTPUT RISE/FALL TIME
vs. TEMPERATURE
4.98
450
60
CURRENT LIMIT
vs. FIELD INPUT VOLTAGE
5.00
500
10
-40
LDO OUTPUT VOLTAGE
vs. TEMPERATURE
5.02
550
4.90
34
AMBIENT TEMPERATURE (°C)
5.04
100
24
SUPPLY VOLTAGE (V)
5.06
600
14
SUPPLY VOLTAGE (V)
I5VOUT = 5mA
5.08
4
36
I5VOUT = 0mA
5.08
4.7
5.10
5VOUT VOLTAGE (V)
5.3
4.94
6
PROPAGATION DELAY (ns)
5.10
5VOUT VOLTAGE (V)
5.04
I5VOUT = 50mA
5.4
PROPAGATION DELAY (ns)
5VOUT VOLTAGE (V)
5.06
5.5
MAX31914 toc11
I5VOUT = 50mA
5.08
5VOUT OTPUT VOLTAGE (V)
MAX31914 toc10
5.10
LDO OUTPUT VOLTAGE
vs. TEMPERATURE
MAX31914 toc12
LDO LINE REGULATION
VTSELECT = 0
RREF = 100kΩ
550
FALL TIME
500
450
400
350
RISE TIME
-40
10
60
110
TEMPERATURE (°C)
Maxim Integrated │ 7
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Pin Configuration
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N.C.
1
VTSELECT
38
GND
2
37
OP1
N.C.
3
36
OP2
DB0
4
35
OP3
DB1
5
34
OP4
N.C.
6
33
OP5
IN1
7
32
OP6
RT1
8
31
OP7
IN2
9
30
OP8
RT2
10
29
IN8
IN3
11
28
RT8
RT3
12
27
IN7
IN4
13
26
RT7
RT4
14
25
IN6
IN5
15
24
RT6
RT5
16
23
FAULT
RIREF
17
22
UVFAULT
N.C.
18
21
N.C.
VCC24V
19
20
5VOUT
+
MAX31914
EP
Maxim Integrated │ 8
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Pin Description
PIN
NAME
1, 3, 6, 18, 21
N.C.
2
VTSELECT
4
DB0
5
DB1
FUNCTION
No Connection
Selects input trip points to be CMOS or IEC 61131-2 compliant.
Logic 0 = CMOS compliant
Logic 1 = IEC 61131-2 compliant
Debounce (Filtering) Time Select Inputs. These inputs also determine the current switching
frequency. See also Table 1 for details.
DB1
DB0
TIME CONSTANT OF FILTER APPLIED
0
0
0 (no filtering)
0
1
0.025ms
1
0
0.75ms
1
1
3ms
7, 9, 11, 13, 15,
25, 27, 29
IN1–IN8
8, 10, 12, 14,
16, 24, 26, 28
RT1–RT8
17
RIREF
19
VCC24V
Field-Supply Voltage
20
5VOUT
5V Regulator Output
22
UVFAULT
23
FAULT
30–37
OP8–OP1
38
GND
—
EP
Field Input n. IN1 is pin 7 and IN8 is pin 29.
Energyless LED Driver Outputs. Connect to GND if LEDs are not required. RT1 is pin 8 and
RT8 is pin 28.
Current-Limiter Reference Resistor
Indicates Low Supply Voltage Alarm (Active Low)
Indicates Hot Temperature Alarm. This is OR’ed with the UVFAULT indicator (active low).
Logic Output n. OP1 is pin 37. OP8 is pin 30.
Field Ground
Exposed Pad. Must connect EP to the PCB ground plane.
Detailed Description
Principles of Operation
Input Current Clamp
The input pins (IN1–IN8) sense the state (on versus off)
of field sensors by monitoring both the voltage and the
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 voltage 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 pin RIREF and
ground. The voltage at the input pins (IN1–IN8) are
compared against internally set references to determine
if the sensor is on (logic 1) or off (logic 0). The trip points
determining the on/off status of the sensor can be selected
through pin VTSELECT as follows:
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● VTSELECT = 1 selects trip points that satisfy the
requirements of IEC 61131-2 type 1, type 2, and type 3
switches.
● VTSELECT = logic 0 selects trip points that are CMOS
logic compatible and roughly centered approximately
2.5V.
Pins RT1–RT8 must be connected directly to GND to
provide a return path for the input current if LEDs are
not required for visual indication. If VTSELECT = logic 0,
RT1–RT8 must be connected directly to GND. If visual
indication is needed when VTSELECT = logic 0, then
LEDs can be connected to pins OP1–OP8 through external
current-limiting resistors.
Glitch Filter
A digital glitch filter provides debouncing and filtering of the
noisy sensor signals. The time constant of this filter is selectable between 0 (i.e., no filtering), 25µs, 0.75ms, and 3ms.
The selection is achieved through pins DB0 and DB1. The
Maxim Integrated │ 9
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
filtered outputs of the comparators are presented to the logic
output pins, OP1–OP8.
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. See Table 1
for current-switching settings.
Low-Power Current Clamp Switching
The MAX31914 uses a switched current limiter to reduce
power consumption below what is achievable by current
limiting along. The internal filter clock is used to switch
input current between 100% and 20% of the chosen
current limit. For example, if the current limit is set to
2.4mA, the input current will switch between 2.4mA
and 0.48mA. The filter clock switches input current at a
50% duty cycle. The clock period for current switching is
automatically selected by the DB1 and DB0 glitch filter
settings. See Table 1 for current-switching settings.
Temperature Monitoring
The internal junction temperature of the IC is constantly
monitored and an alarm is raised, by asserting the FAULT
pin, if the temperature rises above TALRM.
Supply Voltage Monitoring
A primary 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 and UVFAULT pins, indicating to the microcontroller that the part is experiencing a fault condition and
the data is not to be trusted. Once the field-supply voltage
has recovered and goes above VONUVLO, the FAULT and
UVFAULT pins are released.
Table 1. Debounce/Current Switching Period Settings
DB1
DB0
BINARY VALUE
DEBOUNCE TIME
CURRENT SWITCHING PERIOD
0
0
0
1
0
0
DC (disabled)
1
25µs
8µs
1
0
2
0.75ms
0.25ms
1
1
3
3ms
1ms
24V
SENSOR OUTPUT VOLTAGE
0V
tDELAY
tDELAY
100% ILIMIT
INPUT CURRENT LIMIT
20% ILIMIT
INTERNAL FILTER CLOCK
TIME
COMPARATOR OUTPUT IS LATCHED INTO FILTER ON
RISING EDGE OF CLOCK
Figure 1. Operation of Switched Current Limiter
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Maxim Integrated │ 10
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Powering the Device Through the 5VOUT Pin
The device can also be powered using a 5V supply
connected to the 5VOUT pin. In this case, a 24V supply
is no longer needed and the VCC24V supply must be
kept unconnected (see Figure 2)
In this configuration, the device will always indicate a
UVFAULT and the FAULT pin will always be active (pulled
low). Faults due to the Supply Voltage monitoring and
Temperature Monitoring will not be available.
This configuration has lower power consumption and
heat dissipation since the on-chip 5V voltage regulator is
disabled.
Figure 2. Basic Application Powered Through 5VOUT
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Maxim Integrated │ 11
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Typical Application Circuit
JUMPERS TO
5VOUT AND GND
24V
R1
C0
D1
D0
C1
5VOUT
VCC24V
DB0
C2
DB1
MAX31914
EARTH
C4
VTSELECT
RINX
FIN1–FIN8
C3
IN1–IN8
OP0–OP7
FAULT
RT1–RT8
UVFAULT
RIREF
GND
LED1–
LED8
RREF
GROUND 0V
C5
EARTH
NOTE: NOT ALL THE EXTERNAL COMPONENTS INDICATED ON THE DIAGRAM ARE REQUIRED FOR THE OPERATION OF THE IC.
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Maxim Integrated │ 12
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Table 2. Recommended Components
COMPONENT
DESCRIPTION
REQUIRED/RECOMMENDED/OPTIONAL
C0, C5
4.7nF, 2kV polypropylene capacitor
Recommended
C1
10µF, 60V ceramic capacitor
Required
C2
100nF, 60V ceramic capacitor
Required
C3
100nF, 10V ceramic capacitor
Recommended
C4
4.7μF, 10V low-ESR ceramic capacitor
Required
D0
36V fast zener diode (ZSMB36)
Recommended
D1
General-purpose rectifier (IN4007)
Optional: For reverse-polarity protection.
LED1–LED8
LEDs for visual input status indication
Optional
R1
150Ω, 1/3W MELF resistor
Required
RINX
2.2kΩ, 1/4W MELF resistor
Required
RREF
15kΩ, 1/8W resistor
Required
Note: For higher EFT EMC performance, a minimum 1nF, 1000V capacitor can be added from nodes FIN1–FIN8 to earth ground
or ground. For additional methods to improve EFT robustness, please check the Maxim website regularly for upcoming application
notes currently being developed.
Ordering Information
PART
TEMP RANGE
Chip Information
PINCARRIER
PACKAGE
MAX31914AUI+
-40°C to +125°C
38 TSSOP
Bulk
MAX31914AUI+T
-40°C to +125°C
38 TSSOP
Tape and
Reel
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
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PROCESS: BiCMOS
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.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
38 TSSOP
U38E+3
21-0714
90-0435
Maxim Integrated │ 13
MAX31914
Ultra-Low Power Industrial, Octal,
Digital Input Translator
Revision History
REVISION
NUMBER
REVISION
DATE
0
12/14
Initial release
1
4/15
Fixed IEC diagram and added 5VOUT description.
DESCRIPTION
PAGES
CHANGED
—
11–13
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.
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 and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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