Silicon Laboratories ISOMODEM Si2401, Руководство пользователя

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Si2401
64 Preliminary Rev. 0.9
Reset settings = 1111_0000 (0xF0)
SF6 (DAA6). DAA Low Level Functions 6
Bit D7 D6 D5 D4 D3 D2 D1 D0
Name MINI[1:0] DCV[1:0] ACT[3:0]
Type R/W R/W R/W
Bit Name Function
7:6 MINI[1:0] Minimum Operational Loop Current.
Adjusts the minimum loop current at which the DAA can operate. Increasing the mini-
mum operational loop current can improve signal headroom at a lower TIP/RING volt-
age.
MINI[1:0] Min Loop Current
00 10 mA
01 12 mA
10 14 mA
11 16 mA
5:4 DCV[1:0] TIP/RING Voltage Adjust.
These bits adjust the voltage on the DCT pin of the line-side device, which affects the
TIP/RING voltage on the line. Low voltage countries should use a lower TIP/RING volt-
age. Raising the TIP/RING voltage can improve signal headroom.
DCV[1:0] DCT Pin Voltage
00 3.1 V
01 3.2 V
10 3.35 V
11 3.5 V
3:0 ACT[3:0] AC Termination Select.
ACT[3:0] AC Termination
0000 Real 600
Ω
termination that satisfies the impedance requirements
of FCC part 68, JATE, and other countries.
0011 Global complex impedance. Complex impedance that satisfies global
impedance requirements EXCEPT New Zealand. May achieve higher
return loss for countries requiring complex ac termination.
[220
Ω
+ (820
Ω
|| 120 nF) and 220
Ω
+ (820
Ω
|| 115 nF)].
0100 Complex impedance for use in New Zealand.
[370
Ω
+ (620
Ω
|| 310 nF)]
1111 Complex impedance that satisfies global impedance requirements.