ADSL/SHDSL Chip

Ericsson Microelectronics has announced what it claims is the world's first single-chip low-power analogue front-end for ADSL/SHDSL transceiver solutions.

The PBM 39707 SURFSLIC-CO offers low power and reduced cost and requires a minimum number of external components to reduce board space. This enables a substantial increase in DSL linecard portdensity.

The circuit provides all the analogue functions needed to implement a front-end ADSL (asymmetric digital subscriber line) or SHDSL (symmetric DSL) transceiver.

Functionality provided includes line driver/receiver, AD/DA conversion, filtering, gain control and line termination.

The first versions of the device are provided in a 128 pin LQFP package. Total power consumption is 1.3 W down to 0.9 W depending on line conditions when sending ITU/G.dmt full rate ADSL.

Further power savings are offered by a standby mode in which only the receive path is active. A major contributing factor to the low power consumption figure is the line driver architecture using an active line termination and drive impedance.

With this concept, the traditional passive line termination is minimised in terms of resistor value.

This also results in substantial reductions in losses of power and output voltage swing. For ADSL applications, the SURFSLIC-CO supports both FDM-mode and EC-mode. Analogue echo cancellation is integrated to reduce analogue and digital filtering requirements in both modes.