Trust ADI's Smart Factory Expertise to Guide Your Choice of IO-Link Device Transceiver

by Michael Jackson and Brian Condell

The best IO-Link device transceiver is the one that most closely meets its application requirements. This final blog in the smart factory series discusses factors to consider when selecting an IO-Link device transceiver and shows how the features of Analog Devices’ IO-Link transceivers' portfolio can help to make this process as simple as possible. See the previous blog here.

Connector Pin Functions

One of the first things to consider when selecting an IO-Link device transceiver is the number and type of connector pin functions it supports. Some smart factory devices may only need a C/Q pin for data transfer/switching; the MAX22514 works perfectly for these. However, others may require an IO-Link connection that includes an additional digital input (DIN) to carry a signal from a basic sensor or pushbutton switch, in which case the MAX22515 is a better choice. Yet other devices may also require DIN to be configurable as a digital output (DO) and the MAX22513 offers this extra degree of freedom.

Figure 1. Port pin Functions on IO-Link Device Transceivers

Small Form Factor

As industrial operations become more highly automated, equipment density on the factory floor is rapidly increasing. This is forcing IO-Link sensors and actuators to shrink, making transceiver package size a key feature. Designing an IO-Link device to fit into ultra-small enclosures is not trivial and the MAX22515, provided in a 2.5 x 2mm WLCSP (Wafer Level Chip Scale Package), can help address this challenge.

High Integration with Low Heat Dissipation

An unintended consequence of smaller sensor and actuator enclosures is that power dissipation in the form of heat becomes an even bigger problem. IO-Link devices commonly draw power from an IO-Link Master (a 24V source) but only require low digital level voltages (3-5V) to operate. The large step-down in voltage can result in a significant amount of power being wasted. The conventional approach has been to use an external DC-DC Buck converter, but the additional components increase board size. This problem can be addressed by instead choosing an IO-Link transceiver with a high-efficiency fully integrated DC-DC converter like the MAX22513 which can provide up to 300mA of current from a low output resistance driver (2Ω typical) or alternatively, the MAX22514, which can supply up to 200mA from a 2.4 Ω driver.\

Figure 2. Enclosure Cross section showing Space Saved using the MAX22513 with integrated DC-DC converter

Similarly, an IO-Link transceiver with an integrated oscillator (to act as a clock source for the device microcontroller managing communication link) can save space and reduce the bill of materials (BOM). Both the MAX22513 and the MAX22514 feature an integrated oscillator.

Robustness

The factory floor is a harsh and unforgiving place that can quickly destroy sensitive semiconductor circuits if they are not adequately protected against transient surges and electrostatic discharge (ESD). Analog Devices’ IO-Link transceivers feature integrated ±60V cable interface protection, providing them with the ruggedness required to survive the conditions encountered in industrial environments. In addition, they feature adjustable current limits and slew rate transmitters for optimum electromagnetic compatibility (EMC).

LED Drivers

Some applications require an IO-Link transceiver to drive external status LEDs – the MAX14827A and MAX14828 offer this functionality.

Figure 3. The MAX14827A IO-Link Device Transceiver Configured to Drive LEDs

Communications and Control Interface

Devices microcontrollers come with various communications and control interfaces – therefore for maximum flexibility, Analog Devices’ IO-Link transceivers are designed to accommodate these different interface options, including:

• SPI – MAX22514 or MAX22513
• I2C – MAX22513 or MAX22515
• Pin Mode – MAX22515

Summary

This blog series has shown how IO-Link fully embodies the ‘Smart Factory’ concept. This versatile interface simplifies communication to smart sensors and actuators, combining signaling with power-over-cable technology. It has become one of the key enablers as industrial automation systems become more interconnected and intelligent to accommodate demands for centralized control and optimized production. The table below summarizes the features of device transceivers in Analog Devices’ IO-Link product portfolio.

Figure 4. Table Features the Portfolio of Analog Devices’ IO-Link Device Transceiver