THS6092SLASH3 datasheet(17/46 Pages) TI1

17 / 46 page

THS6042, THS6043

350 mA, ±12 V ADSL CPE LINE DRIVERS

SLOS264G − MARCH 2000 − REVISED DECEMBER 2001

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

APPLICATION INFORMATION

ADSL (continued)

One problem in the ADSL CPE area is noise. It is imperative that signals received off the telephone line have

as high a signal-to-noise ratio (SNR) as possible. This is because of the numerous sources of interference on

the line. The best way to accomplish this high SNR is to have a low-noise receiver such as the THS6062 or

OPA2822 on the front-end. Even if the receiver has very low noise characteristics, noise could be dominated

by the line driver amplifier. The THS6042/3 were primarily designed to circumvent this issue.

The ADSL standard, ANSI T1.413, stipulates a noise power spectral density of –140 dBm/Hz, which is

equivalent to 31.6 nV/

√Hz for a 100-Ω system. Although many amplifiers can reach this level of performance,

actual ADSL system testing has indicated that the noise power spectral density may be required to have

≤ –150

dBm/Hz, or

≤ 10 nV/√Hz. With a transformer ratio of 1:2, this number reduces to less than 5 nV/√Hz. The

THS6042/3, with an equivalent input noise of 2.2 nV/

√Hz, is an excellent choice for this application. Coupled

with a low 2.1 pA/

√Hz noninverting current noise, a very low 11 pA/√Hz inverting current noise, and low value

resistors, the THS6042/3 ensures that the received signal SNR is as high as possible.

THS6092/3 датащи(PDF) 17 Page - Texas Instruments