SI3015-FS Silicon Laboratories Inc, SI3015-FS Datasheet - Page 81

• Manufacturer Part Number: SI3015-FS
• Description: SI2400 ISOMODEM LINE-SIDE
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3015-FS

• Data Format: V.90
• Interface: Serial
• Voltage - Supply: 3.3 V ~ 5 V
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Baud Rates: -

After the BTE, ROV, and BTD bits are all cleared, the
BTE bit can be set to reenable billing tone detection.
Certain line events, such as an off-hook event on a
parallel phone or a polarity reversal, may trigger the
ROV or the BTD bits, after which the billing tone detector
must be reset. The user should look for multiple events
before qualifying whether billing tones are actually
present.
Although the DAA will remain off-hook during a billing
tone event, the received data from the line will be
corrupted (or a modem disconnect or retrain may occur)
in the presence of large billing tones. If the user wishes
to receive data through a billing tone, an external LC
filter must be added. A modem manufacturer can
provide this filter to users in the form of a dongle that
connects on the phone line before the DAA. This keeps
the manufacturer from having to include a costly LC filter
internal to the modem when it may only be necessary to
support a few countries/customers.
Alternatively, when a billing tone is detected, the host
software may notify the user that a billing tone has
occurred. This notification can be used to prompt the
user to contact the telephone company and have the
billing tones disabled or to purchase an external LC filter.
Billing Tone Filter (Optional)
In order to operate without degradation during billing
tones in Germany, Switzerland, and South Africa, an
external LC notch filter is required. (The Si3015 can
remain off-hook during a billing tone event, but modem
data will be lost [or a modem disconnect or retrain may
occur] in the presence of large billing tone signals.) The
notch filter design requires two notches, one at 12 KHz
and one at 16 KHz. Because these components are
fairly expensive and few countries supply billing tone
support, this filter is typically placed in an external
dongle or added as a population option for these
countries. Figure 18 shows an example billing tone filter.
Figure 19 shows the billing tone filter and the ringer
impedance network for the Czech Republic. Both of
these circuits may be combined into a single external
dongle.
L3 must carry the entire loop current. The series
resistance of the inductors is important to achieve a
narrow and deep notch. This design has more than
25 dB of attenuation at both 12 KHz and 16 KHz.
Rev. 1.1
‘
Table 30. Component Values—Optional Billing
RING
From
Line
TIP
Figure 19. Dongle Applications Circuit
FROM
RING
Symbol
LINE
C1,C2
TIP
C3
L3
L4
Figure 18. Billing Tone Filter
3.3 mH, >120 mA, <10 Ω , ±10%
C15
1 µ
R14
7.5 K
Z2
5.6 V
Z3
5.6 V
10 mH, >40 mA, <10 Ω , ±10%
Tone Filters
F, 250 V
Ω
, 1/4 W
0.027 µ F, 50 V, ±10%
0.01 µ F, 250 V, ±10%
3.3 mH, 120 mA
0.027
0.027
C1
C2
L3
C1
C2
L3
µ
µ
F, 50 V
F, 50 V
0.01
3.3 mH, 40 mA
Value
C3
L4
µ
F, 250 V
C3
L4
Si2400
DAA
To
To
Si3015
Chipset
81