DESCRIPTION
ST70134 is the Analog Front End of the STMicroelectronics
ASCOTTM ADSL chipset and when
coupled with ST70135A or ST70235 (DMT
modem) allows to get a T1.413 Issue 2 or G.dmt
compliant solution.
The ST70134 analog front end handles 2 transmission
channels on a balanced 2 wire interconnection;
a 16 to 640Kbit/s upstream transmit
channel and a 1.536Mbit/s to 8.192Mbit/s downstream
receive channel.
This asymmetrical data transmission system uses
high resolution, high speed analog to digital and
digital to analog conversion and high order analog
filtering to reduce the echo and noise in both
receivers and transmitters.
External low noise driver and input stage used
with ST70134 guarantee low noise performances.
The filters, with a programmable cutoff frequency,
use automatic Continuous Time Tuning to avoid
time varying phase characteristic which can be of
dramatic consequence for DMT modem.
It requires few external components, uses a 3.3V
supply. It is packaged in a 64-pin TQFP in order to
reduce PCB area.