Vishay Siliconix today removed a major hurdle in the development of lower system voltages for mobile communications and computing products with the release of the industryıs first power MOSFETs that can operate from voltages as low as 1.8 V.

"The introduction of these new LITTLE FOOT devices signifies that there is finally a solution for load switching at 1.8 V," said Evan Lambka, Product Marketing Manager at Vishay Siliconix. "Lower system voltages mean longer battery life, and they are an essential factor enabling the smaller and lighter cell phones and handheld computers that weıll see in the 21^st century."

Twelve 1.8-V LITTLE FOOT power MOSFETs from Vishay Siliconix are now being sampled. All are p-channel devices, and all set new records for on-resistance at 1.8-V, 2.5-V, and 4.5-V gate drives. The new Si4465DY in the SO-8 package, for example, offers on-resistance of 9 milliohm at 4.5 V, 11 milliohm at 2.5 V, and 16 milliohm at 1.8 V. Compared with previous state-of-the-art power MOSFETs, this represents an improvement of 35% The following table provides key specifications for all 12 devices, which are available in SO-8, TSSOP-8, TSOP-6 and SOT-23 versions.

Click here for table.

The new 1.8-V LITTLE FOOT devices are available with 8-V or 12-V drain-source voltage ratings. When the device is going to be used as a load switch on a regulated railısuch as controlling part of a logic circuitıthe 8-V version is recommended. If the device is going to be used as a power switch for a voltage that can exceed 8 V, then the 12-V device is the preferred choice.

In addition to enabling lower system voltages, the new LITTLE FOOT devices will allow designers to upgrade their systems with a higher-performance, drop-in-replacement device or to choose a smaller power MOSFET package, which will help to make end products smaller and lighter.

Technical Information: email.

Getting impressive on-resistances at 2.5 and 4.5-V gate drive voltages is a great step -- particularly the really nice numbers from the single SO-8 packaged products. But the additional achievement of getting a really acceptable resistance at 1.8 V is a major breakthrough for the portable products market. The numbers with the SOT-23 packages are much higher but are still good and many designers may find them acceptable or designable into their products.

This whole family of products with the same technology allows the designer an across the board choice of a product, or products, that he can use. The one odd thing about the resistance performance is the major changes between the 8-V and the 12-V products when they are in the TSOP-6 and the SOT-23, going up 50% for every gate voltage drop in the TSOP-6 and 100% in the SOT-23, almost a square-law change?

These parts will enable completely new designs in the portable arena and are one of the last stepping stones to driving the supply voltages down from 2.5 V to 1.8 V as a standard across the portable communications and PC markets. As the first to get there Vishay Siliconix should deservably take a large number of the early design wins.