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New IGBT Driver

This paper describes STMicroelectronics ADSL analog line interface solutions.

After a short overview of the ADSL application environment, this article focuses on the implementation of

line drivers. Magnetic circuits such as hybrid or line transformer circuits will not be described in detail.

The ADSL concept

Asymmetric Digital Subscriber Line (ADSL) is a modem technology, which converts existing twisted-pair

telephone lines into access paths for multimedia and high speed data communications.

An ADSL modem is connected to a twisted-pair telephone line, creating three information channels: a

high-speed downstream channel (up to 1.1MHz and 2.2MHz for ADSL2+) depending on the

implementation of the ADSL architecture, a medium-speed upstream channel (up to 135kHz or 230kHz)

and a POTS (Plain Old Telephone Service), split off from the modem by filters.

ADSL allows the wide-band access necessary to transmit media such as movies, television, remote CD-

ROMs via LANs and the Internet into individual workplaces and homes.

Figure 1: Typical spectral representation of a DMT ADSL signal (subscriber side)

135kHz

30kHz

POTS

1.1MHz

Upstream

Downstream

DMT sub-channel

(Discrete Multi-Tone)

160kHz

4.5kHz

STMicroelectronics Solutions for

ADSL Line Interfaces

TA0313

Technical Article