IO-Link master IC for harsh industrial environments

11th December 2013

Nat Bowers

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Datasheet

Linear Technology has announced a new IO-Link master IC which combines a power and communications interface to four remote IO-Link devices (slaves). Designated the LTC2874, it manages four slaves per master IC in order to reduce board space, design complexity and costs while increasing reliability. With a rugged interface and rich feature set, the LTC2874 is ideal for larger systems implementing IO-Link (IEC61131-9) in harsh, industrial environments.

Operating over the industrial temperature range from -40°C to 85°C, the LTC2874 features an automatic Wake-Up Request, and an output supply current-boosting capability for slave start-up. In order to reduce demands on the microcontroller, the WURQ generator produces self-timed wake-up pulses of correct polarity. Preventing thermal overload and maintaining error-free communciation, they also feature saftey mechanisms to manage multiport and repeat WURQs. The current-boosting pulse generator fully implements the start-up current pulse requirements added to the IO-Link v1.1.1 specification.

The LTC2874 also features an onboard Hot Swap controller and external N-channel MOSFET in the power interface. These protect connected devices from inrush currents during start-up and fault conditions. Additionally, it includes an integrated ±50V blocking diodes in the data line interface, and an SPI interface. The blocking diodes protect against faults and high voltage excursions, while the data lines withstand ±8kV HBM ESD without latchup or damage. With all other pins protected to ±6kV HBM, the LTC2874 IO-Link master IC is ideally suited for the harsh PLC environment driving cables up to 20m long. Thanks to the integrated SPI interface, designers can host configure and monitor multiple parameters including input supply voltage, output power good status, and fault events.

Linear has increased the flexibility for communication and fault handling in various systems with programmable controls for Hot Swap current limit foldback, circuit breaker timers, noise suppression filters and current sinking. Operating over an 8V to 30V range, the new ICs are also suited for legacy Standard I/O mode and other industrial applications. Enabling hot-plugging without sparking (which might otherwise reduce connector lifetime), a cable-sensing feature ensures that power supply outputs turn on only after cables are connected.

Supplied in a 5 mm × 7 mm QFN or TSSOP package, the RoHS-compliant LTC2874 is available now priced from $7.94 (USD) each in 1,000-piece quantities. The LTC2874 complements the LT3669 IO-Link device (slave) PHY interface.