Galvanic-Isolated High-Side Smart Power Switch with Diagnostic, Safety, and Protection Features

The STMicroelectronics ISO8200AQ galvanic-isolated octal high-side smart power switch enhances diagnostics and system management by providing a 20MHz SPI port allowing both per-channel over-temperature signalization and efficient daisy-chaining of multiple devices. A power-good output indicates the status of the process-side power supply.

The device enlarges 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 assures superior safety 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 preset safe minimum threshold voltage, and complements the fault output pin that indicates communication errors or over-temperature conditions.

With eight channels, each having on-resistance of 0.12Ω (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.

ISO8200AQ block diagram. (click on block diagram to enlarge)

Built-in protection features of the ISO8200AQ further enhance safety, including 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, overvoltage protection by Vcc clamping, and control of the output voltage to prevent damage due to switch off of inductive loads.

In addition, the ISO8200AQ satisfies the requirements for IEC 61131-2 relating to functional properties and characteristics of programmable controllers.

An extensive ecosystem of support tools helps users get the best performance from the ISO8200AQ. These include the X-NUCLEO-OUT02A1 demonstration board, which simplifies evaluating and fine-tuning the setup, and the STSW-IFAPGUI graphical user interface that helps visualize the device behavior.

The X-NUCLEO-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.

Summary of key features:

  • Vdemag = VCC – 45V (per channel)
  • RDS(on) = 0.11Ω (per channel)
  • IOUT = 0.7A (per channel)
  • VCC = 45V
  • SPI interface with daisy chaining
  • 5V and 3.3V TTL/CMOS and μC compatible I/Os
  • Common output enable/disable pin
  • Fast demagnetization of inductive loads
  • Reset function for IC outputs disable
  • Very low supply current
  • Undervoltage shutdown with auto restart and hysteresis
  • Short-circuit protection
  • Per-channel overtemperature protection
  • Thermal independence of separate channels
  • Case overtemperature protection
  • Loss of Ground and Supply protections
  • Overvoltage protection (VCC clamping)
  • Common fault open drain output
  • Power GOOD open drain output
  • High common mode transient immunity
  • ESD protection

The ISO8200AQ is available now in 9mm x 11mm 32-pin TFQFPN32, priced from $3.125 for orders of 1000 pieces.

STMicroelectronics NV
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