SI3018FS Silicon Laboratories Inc, SI3018FS Datasheet - Page 28

• Manufacturer Part Number: SI3018FS
• Description: DAA - MODEM FA19 TELECOM/DATACO
• Manufacturer: Silicon Laboratories Inc

Si3018/19/10
The MINI[1:0] bits select the minimum operational loop
current for the DAA, and the DCV[1:0] bits adjust the
DCT pin voltage, which affects the TIP/RING voltage of
the DAA. These bits permit important trade-offs for the
system designer. Increasing the TIP/RING voltage
provides more signal headroom, while decreasing the
TIP/RING voltage allows compliance to PTT standards
in low-voltage countries such as Japan. Increasing the
minimum operational loop current above 10 mA also
increases signal headroom and prevents degradation of
the signal level in low-voltage countries.
Finally,
requirements for line seizure versus line hold. Japan
mode may be used to satisfy both requirements.
However, if a higher transmit level for modem operation
is desired, switch to FCC mode 500 ms after the initial
off-hook. This satisfies the Australian dc termination
requirements.
5.12. AC Termination
The Si3056 has four ac termination impedances with
the Si3018 line-side device and sixteen ac termination
impedances with the Si3019 line-side device. The ACT
and ACT2 bits select the ac impedance on the Si3018
line-side device. The ACIM[3:0] bits select the ac
impedance on the Si3019. The available ac termination
settings are listed for the line-side devices in Tables 17
and 18.
The most widely used ac terminations are available as
register
requirements. The real 600 Ω impedance satisfies the
requirements of FCC part 68, JATE, and many other
countries. The 270 Ω + (750 Ω || 150 nF) satisfies the
requirements of TBR21 (ACT = 0, ACT = 1, or ACIM
[3:0] = 0010).
28
Figure 21. TBR21 Mode I/V Characteristics,
DCV[1:0] = 11, MINI[1:0] = 00, ILIM = 1
20
45
40
35
30
25
15
10
5
.015 .02 .025 .03 .035 .04 .045 .05 .055 .06
Australia
options
to
TBR21 DCT Mode
has
Loop Current (A)
satisfy
separate
various
dc
global
termination
PTT
Rev. 1.05
Table 17. AC Termination Settings for the Si3010
0
1
0
1
ACT
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
ACIM[3:0]
Table 18. AC Termination Settings for the
0
0
1
1
ACT2
and Si3018 Line-Side Devices
Si3019 Line-Side Device
Real, nominal 600 Ω termination that sat-
isfies the impedance requirements of
FCC part 68, JATE, and other countries.
Complex impedance that satisfies global
impedance requirements.
Complex impedance that satisfies global
impedance requirements EXCEPT New
Zealand. Achieves higher return loss for
countries requiring complex ac termina-
tion. [220 Ω + (820 Ω || 120 nF) and
220 Ω + (820 Ω || 115 nF)]
Complex impedance for use in New
Zealand. [370 Ω + (620 Ω || 310 nF)]
600 Ω
900 Ω
270 Ω + (750 Ω || 150 nF) and 275 Ω
+ (780 Ω || 150 nF)
220 Ω + (820 Ω || 120 nF) and
220 Ω + (820 Ω || 115 nF)
370 Ω + (620 Ω || 310 nF)
320 Ω + (1050 Ω || 230 nF)
370 Ω + (820 Ω || 110 nF)
275 Ω + (780 Ω || 115 nF)
120 Ω + (820 Ω || 110 nF)
350 Ω + (1000 Ω || 210 nF)
200 Ω + (680 Ω || 100 nF)
600 Ω + 2.16 µF
900 Ω + 1 µF
900 Ω + 2.16 µF
600 Ω + 1 µF
Global complex impedance
AC Termination
AC Termination