SI2493-C-FS Silicon Laboratories Inc, SI2493-C-FS Datasheet - Page 88

• Manufacturer Part Number: SI2493-C-FS
• Description: IC ISOMODEM SYSTEM-SIDE 16SOIC
• Manufacturer: Silicon Laboratories Inc

Specifications of SI2493-C-FS

• Mfg Application Notes: SI2493/57/34/15/04, Appl Note AN93
• Data Format: V.21, V.22, V.23, V.29, V.32, V.34, V.90, V.92, Bell 103, Bell 212A
• Baud Rates: 56k
• Interface: UART
• Voltage - Supply: 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AN93
3.3.33. U68 (ITC2)
U68 is a bit-mapped register with bits 15:3 reserved.
Reading these bits returns zero. Bits 4 and 2:0 are all
read/write (see Table 55).
Bit 2 (BTE) = 0
BTE = 1
of the line-derived power supply during a billing tone
event. When off-hook, if BTE = 1
the dc termination is increased to 800 Ω to reduce loop
current. If BTE and U70[9] (RIM) are set to 1
interrupt from U70[1] (RI) also occurs when BTD goes
to 1
Bit 1 (ROV) is normally 0
excessive receive input level. ROV is cleared by writing
it to 0
Bit 0 (BTD) = 0
is detected. BTD is cleared by writing a 0
U68 resets to 0x0000 with a power-on or manual reset.
88
Bit
5:4
3:2
7
6
1
0
b
(high).
b
.
Reserved Read returns zero.
DCV[1:0] TIP/RING Voltage Adjust.
b
, the DAA automatically responds to a collapse
Name
DCR
OHS
RZ
RT
b
b
normally but is set to 1 if a billing tone
(default) is disabled by default. When
DC Impedance Selection.
0 = 50 Ω dc termination slope is selected. This mode should be used for all standard
applications.
1 = 800 Ω dc termination is selected.
On-Hook Speed.
See OHS2.
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 voltage. Raising the
TIP/RING voltage can improve signal headroom.
Ringer Impedance.
0 = Maximum (high) ringer impedance.
1 = Synthesize ringer impedance. C15, R14, Z2, and Z3 must not be installed when setting this
bit. See the “Ringer Impedance” section in “AN93: Si2493/Si2457/Si2434/Si2415/Si2404
Modem Designer’s Guide”.
Ringer Threshold Select.
Used to satisfy country requirements on ring detection. Signals below the lower level do not
generate a ring detection; signals above the upper level are guaranteed to generate a ring
detection.
0 = 11 to 22 V
1 = 17 to 33 V
DCV[1:0]
00
01
10
11
b
and is set to 1
DCT Pin Voltage
rms
rms
b
3.1 V
3.2 V
3.35 V
3.5 V
and BTD goes high,
.
.
Table 54. U67 Bit Map (Continued)
b
b
to BTD.
to report an
b
, an
Rev. 0.9
3.3.34. U6A (ITC4)
U6A is a bit-mapped register with bits 15:3 and 1:0
reserved. Reading these bits returns zero. Bit 2 is read-
only. (See Table 56.)
Bit 2 (OVL) is a read-only bit that detects a receive
overload. This bit is similar to U68[1] (ROV) except OVL
clears itself after the overload condition is removed.
Function