Overview
The SCLT3-8BT8-TR, produced by STMicroelectronics, is an octal industrial digital input IC designed to significantly reduce the power dissipation of digital input modules. This component features current-sinking inputs that can be configured to meet Type 1, Type 2, or Type 3 characteristics as per the IEC 61131-2 standard with minimal external components. It includes a serial interface that translates, conditions, and serializes data to CMOS-compatible signals via SPI, enhancing the density of I/O modules by reducing power dissipation and the number of optocouplers required.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Number of Digital Inputs | 8 | - |
| Input Current Limitation (Typical) | 2.35 mA (Type 1 and Type 3) | mA |
| Reverse Polarity Capability | 35 V | V |
| SPI Clock Frequency | 0.1 to 2 MHz | MHz |
| Operating Ambient Temperature Range | -40 °C to 105 °C | °C |
| Package Types | HTSSOP-38, QFN-48L | - |
| EMC Compliance | IEC 61000-4-2 level 4: ±15 kV (air discharge), ±8 kV (contact discharge) | - |
| Surge Protection | IEC 61000-4-5 Surge ±1 kV /42 Ω with minimum 1 kΩ pulse resistor | - |
Key Features
- Eight current-sinking digital inputs with serializer
- Meets Type 1, 2, and 3 characteristics of IEC 61131-2 standard
- Adjustable and accurate input current limitation for low power and heat dissipation
- Integrated glitch and debounce filter with selectable delay time (20 µs to 3 ms)
- SPI-Compatible Serial Interface (8-bit or 16-bit mode with parity check and diagnostics)
- Daisy-Chain SPI to reduce isolation channels
- 5 V voltage regulator
- Energyless Field-Side LED drivers for visual status indication
- Complies with IEC 61000-4-2 and IEC 61000-4-5 standards for EMC robustness
Applications
The SCLT3-8BT8-TR is particularly suited for applications in factory automation where current limitation is crucial. Key applications include:
- Programmable Logic Controllers (PLCs)
- Input modules
- CNC control systems
- Motor control systems
Q & A
- What is the primary function of the SCLT3-8BT8-TR?
The primary function is to provide eight current-sinking digital inputs that can be configured to meet various IEC standards, reducing power dissipation and enhancing I/O module density.
- What are the input current limitation values for Type 1 and Type 3 inputs?
The typical input current limitation for Type 1 and Type 3 inputs is 2.35 mA.
- What is the operating ambient temperature range of the SCLT3-8BT8-TR?
The operating ambient temperature range is from -40 °C to 105 °C.
- What types of packages are available for the SCLT3-8BT8-TR?
The component is available in HTSSOP-38 and QFN-48L packages.
- Does the SCLT3-8BT8-TR have built-in EMC protection?
- How does the SPI interface work on the SCLT3-8BT8-TR?
The SPI interface can operate in 8-bit or 16-bit mode, with options for parity check and diagnostics. Data transfer is managed by the chip select and clock signals.
- What is the purpose of the integrated glitch and debounce filter?
The filter reduces glitches and noise at the inputs, enhancing transient immunity and making an analog RC filter unnecessary for most applications.
- Can the SCLT3-8BT8-TR be used in daisy-chain configurations?
- What is the role of the energyless Field-Side LED drivers?
The energyless Field-Side LED drivers provide visual status indication without additional power consumption.
- How can I evaluate the SCLT3-8BT8-TR?
The component can be evaluated using the STEVAL-IFP030V1 evaluation board. Refer to AN2846 for detailed application guidelines.
