Elonics' multi-band, multi-standard receiver chip readies for launch

EDN Europe, 19 Sep 2008

Elonics, a fabless semiconductor company specialising in mixed-signal and RF devices, is currently evaluating the production silicon of its E4000 multi-band CMOS tuner chip, succeeding the early-silicon version that the company has had for some months. E4000 provides a single, all-CMOS, low-power RF front end that covers all standards and all modulation schemes for the complete band from 64 MHz to 1.7 GHz, for use in portable media products and other battery-powered devices that have off-air reception. Digital TV and radio signals covered include DVB-T, ISDB-T, T-DMB, DVB-H, ISDB-H, DMB-T, DAB and FM radio. Elonics’ designers anticipate a power consumption of 100 mW, or less, depending on signal type, from a 1.5-V DC rail reserved for analogue functions. The company uses an architecture that it calls DigitalTune; fundamentally a zero-IF (intermediate-frequency) – or direct-conversion – layout, DigitalTune enables complete digital control of each functional block in the receiver chain. In particular, you can control the gain distribution through the signal path to optimise it for any specific signal type and signal strength; you can configure elements such as an RF tracking filter and choose whether to concentrate the gain ahead of it or downstream of it. In this way, you can optimise the noise and sensitivity of the devices for each signal. Elonics designed the chip to be a flexible front-end supporting digital demodulation of all relevant broadcast standards. Noting that it is often hard to get ADCs to perform as well as their nominal specifications indicate, design software assists with configuring the chip so that the front-end feeds the optimum signal to the baseband. The E4000’s signal path includes low-noise amplifier and power detector – the “high-level” view of the design philosophy is, the company says, “to take a very good LNA, and make it multi-standard and tunable” – plus six gain stages and three filter stages. The filters can be band-pass or low-pass, and a channel-filter function permits digital control of corner-frequency and bandwidth over a wide range. A digital controller – in effect, a state machine – controls the detailed configuration of the RF path; you would issue commands to that block from the baseband depending on the expected signal type. DigitalTune supports real-time monitoring and correction of the receiver according to signal conditions; the company has been working with potential customers’ development teams to adjust expectations, and design flows, in the light of the increased flexibility in the RF stage that this approach brings.
Former CEO and founder of Wolfson Microelectronics, David Milne, has become Chairman of Elonics to assist its management – several of whom are also ex-Wolfson – through the next stages of its growth.