MTC20454 ST Microelectronics, Inc., MTC20454 Datasheet - Page 9

• Manufacturer Part Number: MTC20454
• Description: Quad Integrated Adsl CMOS Analog Front End Circuit
• Manufacturer: ST Microelectronics, Inc.

Power Supply Rejection
The noise on the power supplies for the RX-path must be lower than 50 mVrms in-band white noise for any
AVDD.
The pre-driver drives an external line power amplifier which transmits the required power to the line.
TX Filter
The TX filters act not only to suppress the DMT sidebands but also as smoothing filters on the D/A con-
verter’s output to suppress the image spectrum. For this reason they are realised in a time continuous ap-
proach.
ATU-C-TX Filter
Same filter as ATU-R-RX. Its purpose is now is to remove image frequency of the transmitted signal ac-
cording the ANSI definition.
Linearity of TX
Linearity of the TX is defined by the IM3 product of two sinusoidal signals with frequencies f1 and f2 and
each with 0.25 Vpd amplitude (-6 dB FS) at the output of the pre-driver for the case of a total AGC = 0 dB.
Power Supply Rejection
The noise on the power supplies for the TX-path must be lower than the following:
■
■
Figure 6. Power Supply Rejection
< 50 mVrms in band white noise for AVDD.
< 15 mVrms in band white noise for Pre-driver AVDD.
TX Pre-driver Capability
-40
-50
-60
-70
dB
1k
10k 100k1M 10M
Hz
MTC20454
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