Smart power switch with SPI protects for industry 4.0

To enhance diagnostics and system management, STMicroelectronics includes a 20MHz SPI port in the ISO8200AQ galvanic isolated octal high-side smart power switch. The SPI allows both per-channel over-temperature signalisation and efficient daisy-chaining of multiple devices. A power-good output indicates the status of the process-side power supply.

The device joins ST’s family of galvanic isolated high-side switches, featuring maximum safety and robustness in demanding applications such as industrial PLCs, PCs, or peripherals, and numeric-control machines in conventional factory automation or industry 4.0 smart factory scenarios.

The 2500Vrms built-in galvanic isolation not only assures safety, claims ST, and allows saving space in the final application and additional use for general-purpose isolation. By providing an SPI port with support for daisy chaining, the ISO8200AQ also allows one host to control multiple switches efficiently.

The power-good output alerts the control system in case the supply rail falls below a pre-set safe minimum threshold voltage. It complements the fault output pin that indicates communication errors or over-temperature conditions.

The eight channels each have on-resistance of 0.12 Ohms (typical) and maximum current rating of 0.7A. The ISO8200AQ manages all kinds of resistive, inductive, or capacitive loads with minimal power loss or heat dissipation, assures ST.

Built-in protection features of the ISO8200AQ include short-circuit, channel over-temperature, case over-temperature, and loss of ground or supply protection. There is also under-voltage shut-down with auto-restart and hysteresis, over-voltage protection by Vcc clamping, and control of the output voltage to prevent damage due to switch off of inductive loads. The ISO8200AQ also satisfies the requirements for IEC 61131-2 relating to functional properties and characteristics of programmable controllers.

The company offers an ecosystem of support tools to help users get the best performance from the ISO8200AQ. These include the X-Nucleo-OUT02A1 demonstration board, for evaluating and fine-tuning the setup, and the STSW-IFAPGUI graphical user interface (GUI) that helps visualise the device’s behaviour. The X-Nucelo-OUT02A1 takes advantage of the IC’s internal galvanic isolation between logic and power stages, and adds reverse-polarity protection and EMC precautions meeting IEC61000-4-2, IEC61000-4-4 and IEC61000-4-5, to satisfy industrial safety standards.

The ISO8200AQ is available now in 9.0 x 11mm 32-pin TFQFPN32.

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