ISOFACE™ Output Switches

The ISO1H81xG product family integrates:

• Robust galvanic isolation (UL508 and EN 61131-2 certified) to protect the 3.3V/5V control domain of an industrial control system from the harsh 24V process side
• 8-channel high-side power-switching capabilities of up to 1.2A per channel
• Active current limitation and over temperature protection
• Common diagnostic feedback for over temperature and for V_bb under-voltage.

The ISO1H81xG family offers parallel and serial 3.3V/5V µC-interfaces, facilitating straight forward connection with virtually any µC, µP, ASIC or FPGA. The ISO1H81xG products enable OEM-product designs which meet the stringent EMI requirements of the IEC 61131-2 norm (zone C) applicable for Programmable Logical Controllers (PLC).

Complete integration

The ISOFACE™ ISO1H8xxG product family offers robust and intelligent galvanically isolated switches, interfacing with microcontrollers or bus- ASICs. Its integrated 8-channel high-side power switches can be used to drive any kind of resistive, inductive or capacitive loads.

Robust switches

The maximum nominal load current per channel is 1.2A. If two outputs are combined in parallel, even 2A loads can be switched. Inductive clamping diodes are already integrated. This permits direct switching of inductive loads without a need for additional clamping diodes to absorb the commutation power.

Diagnosis and safety

Each of the switch outputs is fully short-circuit protected and temperature monitored, which is yet another aspect underscoring the extreme ruggedness of the ISOFACE™ output switches. In cases of over-load and over-temperature a diagnostic feedback to the micro-controller or bus-ASIC is provided. Simultaneously the respective output channel is turned off. In addition, to ensure proper switching of the MOSFET output stages, the supply voltage on the load-side (V _bb) is monitored. If a critical minimum level is being reached, the outputs are automatically switched off.

Provided the control command from the microcontroller or bus-ASIC to the ISOFACE™ switching IC has not changed, the auto-restart function will re-activate the output switching channel if and when the over-load or over-temperature or under-voltage situation vanishes. To complete the safety-concept a disable input pin allows to asynchronously turn-off all outputs. In their combination these features greatly improve system safety and provide strong support for the customer’s system maintenance.

Setting the standard in diagnostics

The ISO2H823V established a class of its own in terms of diagnostics: On a channel by channel level, it can distinguish between up to five different types of diagnostic events. Furthermore, it supports five additional types of diagnostics on IC-level. The diagnostic capabilities integrated in the ISO2H823V enable preventive maintenance and in case of un-scheduled down-times greatly helps to expedite locating the error thus shortens the valuable time to system-restart.

Reliability

The high level of functional integration of the ISOFACE™ 8-channel high-side switches substantially reduces the quantity of components required to attain a complete system solution. In consequence, the system stability and reliability are significantly improved and the consumed PCB area can drastically be reduced.