Machine Design

New process makes possible better high-voltage ICs

A new semiconductor manufacturing process is said to make possible ICs with submicron geometry that can withstand as much as 30 V. Dubbed industrial CMOS (iCMOS) by its creators at Analog Devices Inc. (Norwood, Mass.), the process targets high-voltage applications such as factory automation and process controls.

Unlike analog chips using conventional CMOS manufacturing processes, components manufactured on the iCMOS industrial process can work with 30-V supplies while reducing power consumption by up to 85% and package size by 30%.

According to the company, previous CMOS chips used to interface with high-voltage industrial systems necessitated use of extra signal conditioning, signal biasing, and external op amps to get sufficient speed and low power consumption. "Under those conditions, manufacturing technologies capable of handling 30 V were in the range of 3 to 5 microns, and adding digital functionality made them to grow to unacceptable sizes," said Denis Doyle, ADI fellow, Process Development. "iCMOS makes this approach obsolete by enabling the integration of more signal chain functions into a much smaller footprint without compromising performance."

Devices made with the new process are able to operate in electrically noisy environments but without the cost of additional ICs required by other CMOS process technologies. An optional drain extension allows operation at up to 50 V.

Among iCMOS's chief attributes is its ability to fully isolate components from the substrate or each other. That means a single chip can mixand-match 5-V CMOS with higher voltage 16, 24, or 30-V CMOS circuitry, with multiple voltage supplies running to the same chip.

Analog components manufactured on the iCMOS process permit integration of digital logic with high-speed analog circuitry in the space of a submicron monolithic integrated circuit, a footprint that no other generation of high-voltage ICs has been able to provide, says the company. For example, analog/digital converters made with the new process will perform better with lower power consumption than converters made on existing high-voltage CMOS processes, claims the company.

Moreover, the ability to accommodate multiple-voltages on the same chip simplifies the construction of systems that use some types of memory. By allocating on-chip memory to handle digital calibration, for instance, analog/digital converters can be quickly adjusted to account for integral non-linearity, offset gain or other parameters. Additionally, the iCMOS process supports software switching. By defining input-voltage ranges in software, for example, manufacturers can design a single iCMOS component into multiple products, changing the input-voltage range according to each application to reduce inventory costs and simplify production design.

TAGS: Technologies
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