1997-12-02 , ESC-9727
Technology News From Philips Semiconductors

Philips Semiconductors announced today a simple enhancement to its I²C-bus, the de-facto standard for communication between ICs. It provides a straightforward solution to the problem of allowing ICs with different supply voltages to communicate and be controlled, for almost no additional design-in effort or cost.

The two-wire I²C-bus is used in a wide range of microcontroller-based consumer and telecommunications products. Having been adopted by about 50 licensees, and with over 1000 different IC devices available today which include an I²C-bus interface, simplicity was crucial to its emergence as the worldwide de-facto serial bus standard. This latest enhancement, involving the addition of just two low-cost transistors, retains its essential simplicity while answering all communication needs in a complete multi-supply voltage system design. Manufacturers can thus easily integrate new 3.3-volt ICs into existing designs, to raise product performance or reduce power consumption, for almost no extra cost.

Although technically simple, this enhancement directly addresses an issue of growing importance in the electronics world: mixing ICs with different supply voltages in one design. This has come about because of the trend towards lower power consumption and the use of very fine line-widths on the latest VLSI and ULSI devices, which necessitates a reduction in supply voltage for new ICs. These have to operate with the vast array of existing 5 V designs and the level shifting solution allows simple integration, without having to re-design the complete system to operate at 3.3 V and ensuring 100% compatibility between all I²C ICs, regardless of supply voltage.

"This new capability of shifting between voltage levels for the I²C-bus gives designers and manufacturers a simple, effective solution for mixed voltage designs in terms of performance and cost, while maintaining the versatility and simplicity of the I²C-bus", said Theo Claasen, Philips Semiconductors' chief technology officer. "At the same time, the I²C-bus specification has been extended to cover devices operating below 2.7 V, ensuring that the I²C-bus will remain the serial bus of choice for future systems into the next century."

Philips Semiconductors, a division of Philips Electronics NV, headquartered in Eindhoven, The Netherlands, is the ninth largest semiconductor supplier in the world. Philips Semiconductors' innovations in digital audio, video, and mobile technology position the company as a leader in the consumer, multimedia and wireless communications markets. Sales offices are located in all major markets around the world and are supported by systems labs.

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