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High speed protected digital termination array
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CLT01-38S4 adds to the existing current limiter family. Still focusing on power consumption savings, the whole series allows each customer to find the right solution.

The CLT01-38S4 is an octal input termination device with a high speed SPI output. Its maximum input data rate is 400 kbps while the output SPI speed is 6.25 MHz.

As in previous versions, robustness is a key feature of CLT01-38S4. The product is compliant with surge standards defined in IEC 61000-4-x.

It can run all types of sensor according to IEC 61131-2. Type 1 and 3 with a 2.35 mA limited current and type 2 using two inputs per sensor with the correct RREF.

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Errata Sheet
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Data Brief

Key Features

  • 8-input circuit in common ground low side topology
  • Wide range input DC voltage VI: -30 V to 35 V
  • On state threshold: < 11 V with RI= 2.2 kΩ
  • Off state threshold: Iin> 1.5 mA or Vi> 5 V
  • Protected against -30 V reverse polarity
  • Typical ILIM= 2.1 to 2.6 mA adjustable current limiters
  • Tight current tolerance including temperature compensation: ±10%
  • Serial output with an SPI communication bus
  • Clock frequency up to 6.25 MHz
  • CPHA = CPOL = 0 bus master operation
  • Multi CLT operation in daisy chain connection
  • 16-bit mode: 8 bits for data / 8 bits for control
  • Minimum capture time: 4 μs
  • Input data rate: 200 kbps/100 kHz
  • Minimum propagation transfer time: 7 μs
  • 8-bit mode: 8 bits for data
  • Minimum capture time: 2.5 μs
  • Input data rate: 400 kbps/200 kHz
  • Minimum propagation transfer time: 4 μs
  • VCC = -0.3 to +35 V with RC = 2.2 kΩ
  • Ambient temperature range: -25 to +85°C
  • Digital inputs for programmable logic controller and decentralized I/O modules
  • Benefits
  • Enables input to meet type 1, 2 and 3 characteristics of IEC 61131-2 standard
  • Compatible operation with 2 wires proximity sensor according EN 60947-5-2 standard
  • Compact board with surface mount integration and reduced count of isolated couplers
  • Reduces the count of input-output of the bus controller circuit
  • Provides energy-less input LED visual status
  • Enhanced functional reliability
  • Built-in over voltage robustness and immune data transfer
  • Reduced dissipation: 78 mW max. per channel
  • Complies with following standards (RI= 2.2 Ω, RC= 2.2 Ω, C = 33 nF):
  • Electrostatic discharge, IEC 61000-4-2:±8 kV contact discharge±15 kV air discharge
  • Electrical transient immunity IEC 61000-4-41:FSCK= 6.25 MHz, ±3 kVFSCK= 10 kHz, ±4 kV
  • Voltage surge IEC 61000-4-5Input: ±15 kVPower supply: ±2.5 kV

Design Resources


Technical Documentation

Product Specifications

Description Version Size
DB1923: High speed protected digital termination array
1.0 284 KB

Application Notes

Description Version Size
AN4625: STEVAL-IFP023V1 evaluation board for CLT01-38S4 input termination
1.0 631 KB

Technical Notes & Articles

Description Version Size
TN1173: Packing information for IPAD™, protection, rectifiers, thyristors and AC Switches
3.1 333 KB

Related Tools and Software

Related Tools and Software

Part Number Description
X-NUCLEO-PLC01A1 Industrial input/output expansion board based on VNI8200XP and CLT01-38SQ7 for STM32 Nucleo
STEVAL-IFP023V1 16-bit digital input card based on the CLT01-38S4 high-speed protected digital termination array

Publications and Collaterals


Description Version Size
Current limiters for fast digital automation inputs
1,273 KB

Selection Guides

Description Version Size
Protection devices and integrated EMI filtering selection guide
1,537 KB


Description Version Size
Products and Solutions for Factory Automation and Control
Jan 2015 3,105 KB

Sample & Buy

Part Number Marketing StatusPackagePacking TypeOrder From STUnit Price (US$)*
@ 1000
Distributor AvailabilityRoHS Compliance GradeDownload
Material Declaration**
CLT01-38S4ActiveHTSSOP38Tube-3.408Distributor reported inventory date: 2016-02-29
Distributor NameRegionStockMin. order
CLT01-38S4-TRActiveHTSSOP38Tape And Reel-3.408Distributor reported inventory date: 2016-02-29
Distributor NameRegionStockMin. order

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors
(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.