EVALUATION KIT AVAILABLE MAX31911 Industrial, Octal, Digital Input Translator/Serializer General Description The MAX31911 industrial interface serializer translates, conditions, and serializes 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 front-end interface circuit 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 onchip lowpass filters allow flexible debouncing and filtering 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. 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 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 possible by input current limiting alone. The future generation version of the MAX31910 and MAX31911 will include energy-less LED drivers while maintaining pin compatibility. Motor Control Block Diagram 24V VCC24V 5VOUT 5V REGULATOR SUPPLY MONITOR OR Ordering Information appears at end of data sheet. TEMP MONITOR RIREF RT1 CRC GEN. LP FILTER SENSORS VREF RT8 SIN µCONTROLLER OR ISOLATION MODESEL VOLTAGE COMPARATOR CLK INPUT CHANNEL 0 IN8 GND FAULTB DB0 DB1 CURRENT LIMITER IN1 5V MAX31911 VREF SERIALIZER INPUT CHANNEL 7 CS 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 MAX31911 Industrial, Octal, Digital Input Translator/Serializer ABSOLUTE MAXIMUM RATINGS (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 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 (qJA)...........37°C/W Junction-to-Case Thermal Resistance (qJC)..................2°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 (Note 2) PARAMETER SYMBOL Field Supply Voltage VCC24V Field Inputs Voltage VINn Logic Inputs Voltage VLOGIC Current-Limit Setting Resistor Field Input Data Rate Maxim Integrated CONDITIONS (Note 3) TYP MAX UNITS 7 36 V -0.3 36 V 0 RREF fIN MIN (Note 4) 5.5 V 15 kI 200 kHz 2 MAX31911 Industrial, Octal, Digital Input Translator/Serializer DC ELECTRICAL CHARACTERISTICS (VCC24V = 7V to 36V, TJ = -40NC to +150NC, unless otherwise noted.) (Note 2) PARAMETER Field-Supply Current SYMBOL CONDITIONS ICC24V IN1–IN8 = 24V, 5VOUT = open, RT1–RT8 = GND, all logic inputs open MIN TYP MAX UNITS 1.4 2.0 mA 9 10 V Field-Supply UVLO Off/On VONUVLO Field-Supply UVLO On/Off VOFFUVLO Field Input Threshold Highto-Low VIN-(INF) 2.2kI external series resistor Field Input Threshold Low-toHigh VIN+(INF) 2.2kI external series resistor 8.5 Field Input Hysteresis VHYS(INF) 2.2kI external series resistor 1 V Input Threshold High-to-Low (at IC pin) VTH-(INP) 2.5 V Input Threshold Low-to-High (at IC pin) VTH+(INP) 3.5 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) tFILTER Filter Time Constant Linear Regulator Output V5VOUT 7 8 V 6 7.5 V 2 10 4 V V 2.2 2.4 2.6 mA DB1/DB0 = 0/0: no filtering DB1/DB0 = 0/1 DB1/DB0 = 1/0 DB1/DB0 = 1/1 0.008 0.25 1.0 0 0.025 0.75 3 0.038 1.1 4.5 Max ILOAD = 50mA 4.75 5.0 5.25 V 10 20 mV ms Regulator Line Regulation dVREGLINE ILOAD = 50mA 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 Logic-Input Trip Point VIH-IL 0.3 x V5VOUT 0.5 x V5VOUT 0.7 x V5VOUT V IIL -50 -30 -15 FA Logic-Input Leakage Current Overtemperature Alarm Maxim Integrated TALRM 4.0 V 135 NC 3 MAX31911 Industrial, Octal, Digital Input Translator/Serializer AC ELECTRICAL CHARACTERISTICS (VCC24V = 7V to 36V, TJ = -40NC to +150NC, unless otherwise noted.) (Note 2) PARAMETER Field Input Pulse Width SYMBOL tPW ESD CONDITIONS No external capacitors on pins IN1IN8 MIN TYP MAX UNITS µs 1 HBM, all pins ±2 HBM, IN1-IN8 with respect to GND ±15 kV AC ELECTRICAL CHARACTERISTICS: SPI INTERFACE (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 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 Clock Pulse Frequency fCLK (Notes 6, 10) DC SIN to CLK Setup Time Propagation Delay, CLK to SOUT ns 25 MHz 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 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. Maxim Integrated 4 MAX31911 Industrial, Octal, Digital Input Translator/Serializer Typical Operating Characteristics (TA = +25°C, RREF = 15kω, unless otherwise noted.) POWER-SUPPLY CURRENT vs. VCC24V FIELD SUPPLY 1.45 1.40 1.55 1.50 1.45 5 25 10 20 30 40 INPUT CURRENT LIMIT vs. TEMPERATURE INPUT CURRENT LIMIT vs. FIELD INPUT VOLTAGE INPUT VOLTAGE HYSTERESIS vs. TEMPERATURE 2.5 2.4 2.3 2.0 1.5 1.0 -40 10 60 0 110 15 25 7.0 7.8 7.6 ON-OFF THRESHOLD 7.0 Maxim Integrated 110 60 110 LDO LINE REGULATION 5.08 5.06 5.04 5.02 5.00 4.98 4.96 5.10 I5VOUT = 5mA 5.08 5.06 5.04 5.02 5.00 4.98 4.96 4.94 4.94 4.92 4.92 4.90 4.90 TEMPERATURE (°C) 10 TEMPERATURE (°C) 5VOUT VOLTAGE (V) OFF-ON THRESHOLD 60 ON-OFF THRESHOLD LDO LOAD REGULATION 5VOUT VOLTAGE (V) 8.4 10 2.6 -40 MAX31911 toc08 RIN = 2.2I 8.6 -40 2.8 35 5.10 MAX31911 toc07 9.0 7.2 OFF-ON THRESHOLD 3.0 FIELD INPUT VOLTAGE (V) INPUT VOLTAGE HYSTERESIS vs. TEMPERATURE 7.4 3.2 2.0 5 AMBIENT TEMPERATURE (°C) 8.2 3.4 2.2 VINn = 24V 2.0 3.6 2.4 0.5 2.1 RIN = 0I 3.8 MAX31911 toc09 2.6 MAX31911 toc06 2.5 THRESHOLD VOLTAGE (V) 2.7 4.0 MAX31911 toc05 3.0 2.2 THRESHOLD VOLTAGE (V) 0 60 RREF (kI) CURRENT LIMIT (mA) CURRENT LIMIT (mA) 10 -40 TEMPERATURE (°C) 2.8 8.8 2.5 SUPPLY VOLTAGE (V) VINn = 24V 2.9 3.5 0.5 1.40 35 MAX31911 toc04 3.0 15 4.5 1.5 1.35 1.30 MAX31911 toc03 5.5 CURRENT LIMIT (mA) SUPPLY CURRENT (mA) 1.50 MAX31911 toc02 1.60 MAX31911 toc01 1.55 SUPPLY CURRENT (mA) CURRENT LIMIT vs. RREF SUPPLY CURRENT vs. TEMPERATURE 1.60 0 10 20 30 40 5VOUT OUTPUT CURRENT (mA) 50 6 11 16 21 26 31 36 SUPPLY VOLTAGE (V) 5 MAX31911 Industrial, Octal, Digital Input Translator/Serializer Typical Operating Characteristics (continued) (TA = +25°C, RREF = 15kω, unless otherwise noted.) LDO OUTPUT vs. VCC24V FIELD SUPPLY LDO LINE REGULATION 5.04 5.02 5.00 4.98 4.96 5.3 5.2 5.1 5.0 4.9 4.8 4.7 4.94 4.6 4.92 4.5 4.90 4 6 11 16 21 26 31 36 SUPPLY VOLTAGE (V) LDO OUTPUT VOLTAGE vs. TEMPERATURE 5.04 5.02 5.00 4.98 4.96 5.06 5.04 5.02 5.00 4.98 4.96 4.94 4.94 4.92 4.92 4.90 I5VOUT = 5mA 5.08 5VOUT VOLTAGE (V) 5VOUT VOLTAGE (V) 34 5.10 MAX31911 toc12 I5VOUT = 0mA 5.06 4.90 -40 10 60 AMBIENT TEMPERATURE (°C) Maxim Integrated 24 LDO OUTPUT VOLTAGE vs. TEMPERATURE 5.10 5.08 14 SUPPLY VOLTAGE (V) MAX31911 toc13 5VOUT VOLTAGE (V) 5.06 I5VOUT = 50mA 5.4 5VOUT OTPUT VOLTAGE (V) MAX31911 toc10 I5VOUT = 50mA 5.08 MAX31911 toc11 5.5 5.10 110 -40 10 60 110 AMBIENT TEMPERATURE (°C) 6 MAX31911 Industrial, Octal, Digital Input Translator/Serializer Pin Configuration TOP VIEW + DB0 1 28 GND DB1 2 27 SIN IN1 3 26 MODESEL RT1 4 25 CLK IN2 5 24 CS RT2 6 23 SOUT IN3 7 22 IN8 RT3 8 21 RT8 IN4 9 20 IN7 RT4 10 19 RT7 IN5 11 18 IN6 RT5 12 17 RT6 RIREF 13 16 FAULT VCC24V 14 15 5VOUT MAX31911 EP Pin Description PIN NAME 1, 2 DB0, DB1 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 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 25 CLK 26 MODESEL 27 SIN 28 GND — EP Maxim Integrated FUNCTION Debounce (Filtering) Time Select Inputs Current-Limiter Reference Resistor Active-Low Chip-Select Input Serial-Clock Input Mode-Select Input MODESEL = 1: Selects 8-bit shift register MODESEL = 0: Selects 16-bit shift register Serial-Data Input Field Ground Exposed Pad. Must be connected to the PCB ground plane. 7 MAX31911 Industrial, Octal, Digital Input Translator/Serializer Basic Application Circuit 24V JUMPERS TO 5VOUT AND GND R1 5VOUT VCC24V C1 DB0 DB1 C4 VDD_LOGIC MODESEL SIN RINX fIN1–8 MAX31911 CLK CLK IN1–8 CS CS ISOLATION RT1–8 SOUT SOUT FAULT FAULT GND RIREF RREF Detailed Description Input Current Clamp The MAX31911 industrial interface serializer inputs (IN1–IN8) sense the state (on vs. off) of field sensors 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 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 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- Maxim Integrated NOTE: SEE FIGURE 1 FOR ADDITIONAL COMPONENTS NEEDED FOR EMC. mine whether the 0). The trip points sensor satisfy the 1 and 3 switches. to work as a Type sensor is on (logic 1) or off (logic determining the on/off status of the requirements of IEC 61131-2 Type The device can also be configured 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. 8 MAX31911 Industrial, Octal, Digital Input Translator/Serializer 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 information. The status byte contains 1 bit representing the status of the field-supply voltage (UV), 1 bit representing 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 junction 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 connected together in this configuration. See the SerialPort Operation section for more detailed information on operating the SPI interface. Temperature Monitoring The internal junction temperature of the device is constantly monitored. An alarm is raised, by asserting the FAULT pin, if the temperature rises above TALRM. In addition 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. Table 1. Debounce Settings DB1 DB0 BINARY VALUE 0 0 0 0 0 1 1 25Fs 1 0 2 0.75ms 1 1 3 3ms Maxim Integrated DEBOUNCE TIME 9 MAX31911 Industrial, Octal, Digital Input Translator/Serializer Applications Information system to meet or exceed international EMC requirements. Table 2 lists an example device for each component 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 specifications (IEC 61000-4-4, -5, -6, and -2). 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 Table 2. Recommended Components 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 C5 100nF, 100V ceramic capacitor Recommended D0 36V fast zener diode (ZSMB36) Recommended D1 General-purpose rectifier (IN4007) R1 150I, 1/3W MELF resistor Recommended RINX 2.2kI, 1/4W MELF resistor Required RREF 15kI, 1/8W resistor Required Required Optional: For reverse polarity protection. This diode alternatively can be placed in series with the field supply (24V). 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. JUMPERS TO 5VOUT AND GND 24V R1 5VOUT VCC24V C0 D0 C5 C1 DB0 DB1 EARTH C3 C4 VDD_LOGIC MODESEL SIN MAX31911 RINX fIN1–8 CLK IN1–8 CLK CS CS ISOLATION RT1–8 SOUT SOUT FAULT FAULT GND RIREF RREF D1 0V C0 EARTH Figure 1. Typical EMC Protection Circuitry Maxim Integrated 10 MAX31911 Industrial, Octal, Digital Input Translator/Serializer 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, undervoltage, 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 daisychain 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 SIN 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 protocol, 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. SIN MAX31911 SOUT SIN MAX31911 MAX31911 SOUT SOUT TO µCONTROLLER 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] Maxim Integrated 11 MAX31911 Industrial, Octal, Digital Input Translator/Serializer 24V JUMPERS TO 5VOUT AND GND R1 5VOUT VCC24V C0 D0 C1 DB0 DB1 C3 C4 MODESEL VDD_LOGIC MAX31911 SIN RINX fIN1–8 CLK IN1–8 CLK CS CS ISOLATION RT1–8 RIREF SOUT SOUT FAULT FAULT GND RREF D1 0V C0 CLK VCC24V CS C1 SOUT FAULT SIN RINX fIN1–8 MAX31911 IN1–8 JUMPERS TO 5VOUT AND GND 5VOUT DB0 DB1 RT1–8 MODESEL RIREF GND C3 C4 RREF Figure 3. 16-Input Application Circuit Maxim Integrated 12 MAX31911 Industrial, Octal, Digital Input Translator/Serializer CLK SOUT IN8 IN7 IN6 IN5 IN4 IN3 IN2 IN1 CRC4 CRC3 CRC2 CRC1 CRC0 UV OT RES CS IN8 –IN1 VALID Figure 4. SPI Communication Example tCSPW tP2 tSU1 CS tH1 CLK SIN VALID SIN SOUT Figure 5. SPI Timing Diagram 1 Figure 7. SPI Timing Diagram 3 1/fCLK tSU2 tCLKPW tREC CLK CS tR/F CLK SOUT tP1 tR/F Figure 6. SPI Timing Diagram 2 Maxim Integrated Figure 8. SPI Timing Diagram 4 13 MAX31911 Industrial, Octal, Digital Input Translator/Serializer Package Information Chip Information PROCESS: S45JRS Ordering Information PART TEMP RANGE PINPACKAGE MAX31911AUI+ -40NC to +125NC 28 TSSOP Bulk 28 TSSOP Tape and Reel MAX31911AUI+T -40NC to +125NC CARRIER 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. 28 TSSOP-EP U28E+4 21-0108 90-0146 +Denotes a lead(Pb)-free/RoHS-compliant package. T = Tape and reel. Maxim Integrated 14 MAX31911 Industrial, Octal, Digital Input Translator/Serializer Revision History REVISION NUMBER REVISION DATE 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 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 DESCRIPTION PAGES CHANGED — 1-4, 9 1, 5, 6, 8, 10, 12, 13 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 © 2013 Maxim Integrated Products, Inc. 15 Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.