Two new line drivers announced by Texas Instruments (TI) deliver ultra-low distortion, high output drive and high speed for multiple bit rate versions of ADSL (asymmetrical digital subscriber line) Internet access technologies. One of the chips is designed for customer premise equipment applications; the other is tailored to central office equipment requirements. The line drivers are part of TI's aggressive efforts to leverage its world leadership DSP and analog technology in the ADSL communications market. ADSL will greatly improve Internet access speed and allow simultaneous voice and data communications over a single, standard telephone line.

The drive capabilities of TI's new THS6012 line driver make it ideal for central office ADSL equipment including digital subscriber line access multiplexers (DSLAMs), digital loop carriers (DLCs) and central office line cards that need high-peak voltage and current requirements.

TI's new THS6022 line driver is targeted at ADSL personal computer modems and remote terminal applications, which require less current than central office applications. It is also well suited for other forms of xDSL including HDSL (high data rate digital subscriber line) and VDSL (very high data rate digital subscriber line).

Both the THS6012 and THS6022 are offered in TI's patented, thermally enhanced PowerPAD package. This innovative, small-footprint package eliminates the heatsink often required by other ADSL line drivers, allowing higher levels of density in central office ADSL equipment.

Both of these devices offer low distortion of -72dB at 1 MHz over low impedance telephone lines. They feature high-speed, 140 MHz bandwidth at a slew rate of 1000V per microsecond. The THS6012 has a typical output drive capability of 500mA while the THS6022 has 250mA drive. Other characteristics shared by the two devices include independent power supply connections for low cross talk and a wide supply voltage operating range of +/-4.5V to +/-16V.

xDSL

Leveraging its expertise in network access and DSP solutions to deliver ADSL chipsets, TI is enabling extensible, affordable end-to-end interoperable solutions for high-speed remote access to the Internet or wide area network for corporate users and consumers. The company's family of standards-compliant ADSL chipsets deliver the performance and programmability necessary to support evolutionary versions of DSL, in addition to existing xDSL standards.

xDSL high-speed data communication technologies include ADSL, splitterless ADSL, HDSL and VDSL. Service providers are currently testing high-speed data access based on these technologies in U.S. and European markets. Initial broad deployment is expected to begin in late 1998.

With xDSL gearing up rapidly this year the parts needed to actually implement the systems are a little behind in supply if, as I suspect, the market is as keen as I believe it will be. TI has produced these parts to compete in all the markets they see, with all the standards they see as being used. Initially this will give them a large market share of the driver market, with some good products; whether this will work for them long term is difficult to visualize as the technologies and the markets reconcile themselves -- if they will with the present technologies. But there is no doubt that TI has a bucket load of products that can be put in the hopper if there is a clear pattern emerging as to what technology or technologies are winning.

With these two products I like particularly the wide range of usable supply voltages and the low distortions. These parts are derived from the THS6002 which also contained a receiver but I have no doubt that the systems designers indicated that they wanted a lower priced solution for the home/PC driver end of the chain, which is no doubt valid.

As noted, the parts are in TI's PowerPAD package with its solderable center board and they are sampling now with production slated for November; they are priced at $4.80 for the THS6012 and $3.71 for the THS6022, both in 1000-piece lots.