Circuit Protection Misc Protected Digital Input Termination with Serialized State Transfer

The SCLT3-8BT8 provides an 8-line protected digital input termination with serialized state transfer. This device enhances the I/O module density by cutting the dissipation (78 mW per input) and reducing the count of opto-transistors. An adjustable digital filter and an LED driver are embedded in each type 3 input section. Its 2 MHz SPI peripheral output serializes the input state transfer to the I/O module controller.

8-input circuit in common ground low side topology

Wide range input DC voltage V_I: -30 V to 35 V

On state threshold: < 11 V with R_I= 2.2 kO

Off state threshold: I_in> 1.5 mA or V_i> 5 V

Protected against -30 V reverse polarity

2.35 mA active current limiter with 10% tolerance

Drastic dissipation reduction:78 mW max. per input

Input digital filter with adjustable delay:20 µs to 3 ms

Energy-less LED visual status driver

Input logic state transfer through a 2 MHz SPI

Programmable 8 / 16-bit register length

Multi SCLT connection in daisy chain

Chip temperature OTA and under voltage UVA alarms

Multi parity bits and power loss detection with stop bits

Drastic reduction of isolated coupler count and I/O of the field bus ASIC

Power supply and input protection, R_I= 2.2 kO:

IEC 61000-4-4 transient burst: ± 4 kV minimum

IEC 61000-4-5 voltage surge: ± 1 kV minimum

IEC 61000-4-2 ESD: ± 8 kV in contact:± 15 kV in air minimum

Wide range power supply voltage V_C:

+ 9 V to + 35 V with 10 mA output current

Protected against -30 V reverse polarity