Software radio chip moves to CMOS

Paul Boughton

Lime Microsystems, the inventor of the field programmable RF (FPRF) concept, has moved to CMOS process technology for its second generation software radio.

The LMS7002M has already taped out in 65nm CMOS technology to significantly reduce the cost of FPRF transceiver technology and significantly reduce the power consumption. The chip also integrates 2x2 MIMO functionality and significantly extends the spectrum coverage. This makes LMS7002M ideal for a host of consumer and professional applications.

The LMS7002M supports all cellular standards and frequencies, including 2G, 3G and 4G / LTE and their TDD / FDD variants among numerous other standards such as WiFi. It features DSP functions, an 8051 microcontroller, multiple 12-bit ADCs and DACs, LNAs, filters, PLLs and mixers to provide the highest level of integration. These elements can also be used as cost-effective standalone parts and the open architecture allows each function to be accessed and used separately. For the most demanding applications, external components can be used to supplement or replace the integrated functions.

The chip extends the low frequency operational range down to just 50MHz from the 300MHz baseline of the first generation LMS6002D. This gives the chip a continuous operational spectrum of 50MHz to 3.8GHz, although lower frequencies are supported by accessing individual blocks within the chip.

Lime sees the chip mopping up other functions in a MIMO wireless system, using the individual blocks such as ADC, DAC, DDS, AGC, PLL or RF VGA.
The transceiver's on-chip DSP also enhances the analogue gain and filtering with digital control and is an important factor in reducing the overall power consumption.

New features, such as the on-chip microcontroller, simplify the calibration and installation. The chip is programmed by a serial bit stream, and designed using a free open source configuration tool suite.

The LMS7002M can operate from a single supply rail of 1.8V with individual blocks capable of being powered down when not required for further power savings. This makes it suitable for a wide range of battery and mains powered mobile communications devices - from professional devices, such as small cells and software-defined radios, to consumer, machine to machine (M2M) and military radio applications.

"The flexibility, low power consumption, functionality and price of the LMS7002M FPRF, makes it an exceptionally disruptive entry to the transceiver chipset market,” said Ebrahim Bushehri, CEO of Lime. “Our new architecture delivers an industry leading transceiver function for a fraction of the cost of existing solutions. And it can be configured to perform many of the functions used within the chip as standalone parts too."

Sampling will start in Q3 2014.

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