SI3015-BS Silicon Laboratories Inc, SI3015-BS Datasheet - Page 23

• Manufacturer Part Number: SI3015-BS
• Description: IC ISOMODEM LINE-SIDE 16SOIC
• Manufacturer: Silicon Laboratories Inc
• Type: Enhanced Global Direct Access Arrangementr

Specifications of SI3015-BS

• Package / Case: 16-SOIC (3.9mm Width)
• Data Format: V.90
• Interface: Serial
• Voltage - Supply: 3.3 V ~ 5 V
• Mounting Type: Surface Mount
• Product: Modem Module
• Supply Current: 0.3 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Baud Rates: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

mode interference, or noise coupling. As shown in
Figure 19 on page 16, the C1, C2, C4, C24, and C25
capacitors isolate the Si3024 (system-side) from the
Si3014 (line-side). All transmit, receive, control, ring
detect, and caller ID data are communicated through
this barrier. Y2 class capacitors may be used for the
isolation barrier to achieve surge performance of 5 kV or
greater.
The ISOcap communications link is disabled by default.
The PR bits in register 3Eh must be cleared, and the
sample rate must be set in register 40h/42h. No
communication between the Si3024 and Si3014 can
occur until these conditions are set.
Off-Hook
The communication system generates an off-hook
command by writing a logic 1 to bit 0 (line 1) or bit 10
(line 2) of slot 12. The off-hook state is used to seize the
line for an incoming/outgoing call and can also be used
for pulse dialing. When in the on-hook state, negligible
dc current flows through the hookswitch. In the off-hook
state, the hookswitch transistor pair, Q1 and Q2, turn
on.
The net effect of the off-hook signal is the application of
a termination impedance across TIP and RING and the
flow of dc loop current. The termination impedance has
both an ac and dc component.
When executing an off-hook sequence, the Si3038
requires 1548/Fs seconds to complete the off-hook and
provide phone line data on the ac link. This includes the
12/Fs filter group delay. If necessary, for the shortest
delay, a higher Fs may be established prior to executing
the off-hook. The delay allows line transients to settle
prior to normal use.
DC Termination
The Si3038 has three programmable dc termination
modes, selected with the DCT[1:0] bits in register 5Ch.
Japan Mode (DCT[1:0] = 01 b), shown in Figure 21, is a
lower voltage mode and supports a transmit full scale
level of –2.71 dBm. Higher transmit levels for DTMF
dialing are also supported. See “DTMF Dialing” on
page 26. The low voltage requirement is dictated by
countries such as Japan and Malaysia.
Australia has separate dc termination requirements for
line seizure versus line hold. The designer can use
Japan mode to satisfy both requirements. However, if it
is desirable to have a higher transmit level for modem
operation, the designer can switch to FCC mode
500 ms after the initial off-hook. This will also satisfy the
Australian dc termination requirements.
Rev. 2.01
.
FCC Mode (DCT[1:0] = 10 b), shown in Figure 22, is the
default dc termination mode and supports a transmit full
scale level of –1 dBm at TIP and RING. This mode
meets FCC requirements in addition to the requirements
of many other countries.
CTR21 Mode (DCT[1:0] = 11 b), shown in Figure 23,
provides current limiting, while maintaining a transmit
full scale level of –1 dBm at TIP and RING. In this mode,
the dc termination will current limit before reaching
60 mA.
Figure 21. Japan Mode I/V Characteristics
Figure 22. FCC Mode I/V Characteristics
10.5
9.5
8.5
7.5
6.5
5.5
10
12
10
11
6
9
8
7
6
9
8
7
.01 .02 .03 .04 .05 .06 .07 .08 .09 .1 .11
.01 .02 .03 .04 .05 .06 .07 .08 .09 .1
Japan DCT Mode
Loop Current (A)
FCC DCT Mode
Loop Current (A)
Si3038
.11
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