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IES inside: SICK exploits new chip platform for its electromagnetic sensors
Waldkirch, April 2006 – SICK is presenting inductive and magnetic sensors with a completely new type of chip technology at the Hanover Industrial Trade Fair 2006. The integrated electronic switch (IES) is an extremely miniaturised platform which offers flexible sensor solutions with improved performance. The most conspicuous external feature: with its new type of packaging technology, the 1.6 mm narrow IES chip offers a hitherto unparalleled level of sensor miniaturisation. The first products in which the IES chip is used are MZT6 and MZN1 magnetic cylinder sensors, MM08, MM12, and MM18 magnetic proximity sensors, and the inductive sensors of the IM08, IM12, IM18 and IM30 series.

With the IES, SICK also underlines its technological leadership in electromagnetic sensors. Improved repeatability, the same form of detection fields for all sensors of the same type, as well as greater flexibility and improved robustness within the inductive and magnetic sensor family, were the most important reasons for developing the IES.

CMOS technology with high voltage and EEPROM options

The IES is based on a CMOS technology with high voltage and EEPROM options. Depending on the product family, the chip’s universal programmable sensor front-end allows the connection of both LC resonant circuits for inductive proximity switches and MR bridges for magnetic proximity and cylinder sensors. While the coils of the LC resonant circuit were designed and optimised using finite element method (FEM) tools, the MR bridges were developed on the basis of a giant magneto resistance (GMR) technology. The GMR bridge is implemented in thin-film technology and is characterised by high sensitivity. What is new about this GMR bridge is its so-called 2-D magnetic field evaluation, which provides an unambiguous switching signal regardless of the cylinder type or magnetic field characteristics of the transmitting magnets. In other words: mount the sensor, and the usual problems with multiple switching are a thing of the past! And the sensors achieve a considerably more precise switching behaviour, with hysteresis characteristics reduced by several factors – of particular importance in certain applications.

Sensor functions in the smallest of spaces

In order to reduce the number of external components to a minimum, numerous functions (which would have been very difficult to implement using a conventional design) have been integrated on the chip. These include a universally programmable sensor front-end, followed by high-resolution signal evaluation, and a final digital multi-bit processing for enhanced resistance to EMC effects. Further important functions are the digital adjustability of sensor parameters (such as switching point, hysteresis, output configuration and operating mode), as well as the non-volatile memory of these parameters in an EEPROM. The functionality of the chip is completed with a voltage-stable regulator, and output with integrated short-circuit protection. Thanks to the CSP packaging technology suitable for SMD placement, with which connection between the chip and the electronic card is achieved in the form of wire-wrapped solder nodules directly on the silicon substrate, the IES remains so compact that it can be integrated in the smallest housings available on the market. The chip’s power consumption is extremely low, and thus also the chip’s own warming – which is an enormous advantage for the achievable temperature classes of EX and UL devices.

The novel chip technology opens up new wide-ranging possibilities for various sensor series from SICK – on the one hand because numerous, hitherto critical, applications can now be better solved; on the other hand because the platform contributes towards a further miniaturisation of sensors for automation.