SI3018-F-FSR Silicon Laboratories Inc, SI3018-F-FSR Datasheet - Page 30

• Manufacturer Part Number: SI3018-F-FSR
• Description: Modem Chip Chipset 16-Pin SOIC T/R
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3018-F-FSR

• Package: 16SOIC
• Main Category: Chipset
• Sub-category: Data/Voice
• Typical Operating Supply Voltage: 3.3 V
• Power Supply Type: Digital
• Typical Supply Current: 8.5 mA
• Minimum Operating Supply Voltage: 3 V
• Maximum Operating Supply Voltage: 3.6 V
• Data Rate: 54.6875Kbps
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Pin Count: 16
• Mounting: Surface Mount
• Lead Free Status / Rohs Status: Compliant

Si3050 + Si3018/19
5.16. DC Termination
The DAA has programmable settings for the dc
impedance, current limiting, minimum operational loop
current and TIP/RING voltage. The dc impedance of the
DAA is normally represented with a 50  slope as
shown in Figure 21, but can be changed to an 800 
slope by setting the DCR bit. This higher dc termination
presents a higher resistance to the line as loop current
increases.
For applications requiring current limiting per the TBR21
standard, the ILIM bit may be set to select this mode. In
this mode, the dc I/V curve is changed to a 2000 
slope above 40 mA, as shown in Figure 22. This allows
the DAA to operate with a 50 V, 230  feed, which is the
maximum linefeed specified in the TBR21 standard.
30
Figure 22. TBR21 Mode I/V Characteristics,
Figure 21. FCC Mode I/V Characteristics,
DCV[1:0] = 11, MINI[1:0] = 00, ILIM = 0
DCV[1:0] = 11, MINI[1:0] = 00, ILIM = 1
20
45
40
35
30
25
15
10
12
11
10
5
.015 .02 .025 .03 .035 .04 .045 .05 .055 .06
8
9
7
6
.01 .02 .03 .04 .05 .06 .07 .08 .09 .1 .11
TBR21 DCT Mode
Loop Current (A)
Loop Current (A)
FCC DCT Mode
Rev. 1.31
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 allow important trade-offs to be
made
operational loop current. Increasing TIP/RING voltage
increases signal headroom, whereas 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.
5.17. AC Termination
The Si3018 provides four ac termination impedances
when used with the Si3050. The ACIM[3:0] bits in
Register 30 are used to select the ac impedance setting
on the Si3018. The four available settings for the Si3018
are listed in Table 16. If an ACIM[3:0] setting other than
the four listed in Table 16 is selected, the ac termination
is
programmable digital hybrid can be used to further
reduce near-end echo for each of the four listed ac
termination settings. See "5.28. Transhybrid Balance"
on page 37 for details.
The
impedances when used with the Si3050. The ACIM[3:0]
bits in Register 30 are used to select the ac impedance
setting on the Si3019. The sixteen available settings for
the Si3019 are listed in Table 17.
The most widely used ac terminations are available as
register
requirements. The real 600  impedance satisfies the
requirements of FCC Part 68, JATE, and other country
requirements. The 270  + (750  || 150 nF) satisfies
ACIM[3:0]
Table 16. AC Termination Settings for the
0000
0100
0011
1111
forced
Si3019
between
Australia
options
600 
220  + (820  || 120 nF) and 220  +
(820  || 115 nF)
370  + (620  || 310 nF)
Global complex impedance
Si3018 Line-Side Device
to
provides
signal
600 
to
has
satisfy
AC Termination
headroom
separate
(ACIM[3:0] = 0000).
sixteen
various
ac
dc
and
global
termination
termination
minimum
PTT
The