Toshiba's new technology cuts phase noise in oscillation ICs for wireless communication

Jun 16, 2011

Toshiba Corporation today announced that it has developed noise reduction technology that reduces jitter in radio-frequency signals, cutting phase noise by up to 90 percent. This breakthrough opens the way for a further migration to high-speed wireless communication chips for wireless LAN and WiMAX.

Radio frequency phased locked loops (PLL) in LSI chips were typically structured with analog and digital circuits. As achieving ultra-fine is highly challenging, there is now a shift to all digital PLL using time-to-digital converters (TDC). While digitization reduces circuit size it also increases phase noise -- a degrading displacement in the pulse of a radio frequency signal -- due to larger delay in the TDC’s inverter circuits. Cutting phase noise is essential for high speed communication standards, like WiMAX, which require highly accurate signals. There is the concern that current TDC is sensitive to variations in manufacturing processes that impact on their performance. This raises a need for more robust manufacturability.

To reduce susceptibility variations in mass production and suppress phase noise, Toshiba developed a new TDC integrating interpolation circuits that use a low resistance conductor to connect the output of two inverters. A triple interpolation splits the cycle of output signal of frequency synthesizers, and reduces phase noise by 90 percent. This solution successfully achieves a PLL with stable performance, as it utilizes a stable waveform from the PLL itself as a reference time interval for converting time to digital data, not the delay time of the inverters. In a test chip manufactured with 65nm CMOS process, phase noise was reduced to -104dBc/Hz, 90 percent lower than that of the previous all digital PLL that Toshiba announced at ISSCC2011. Chip size was cut to 0.18 mm2, approximately 80 percent smaller than the analog PLL in a mobile transceiver chip that Toshiba announced at ISSCC2010.

 This achievement will be announced on June 16 at the 2011 VLSI Symposium now being held in Kyoto, Japan.

Explore further: Halogen-free leaded multilayer ceramic capacitors for automotive and general-purpose applications

Provided by Toshiba Corporation

5 /5 (2 votes)
add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Airbnb to expand tax collection efforts

16 hours ago

Online lodging operator Airbnb is expanding its efforts to collect local taxes, responding to complaints that it competes unfairly with the hotel sector.

Jay Z to acquire Wimp music service

17 hours ago

US rap star Jay Z will make a $56-million foray into the music streaming business by taking over the Norwegian service Wimp, its shareholders confirmed Friday.

Scientists trial system to improve safety at sea

18 hours ago

A space scientist at the University of Leicester, in collaboration with the New Zealand Defence Technology Agency and DMC International Imaging, has been trialling a concept for using satellite imagery to ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.