SI3225-G-GQ Silicon Laboratories Inc, SI3225-G-GQ Datasheet - Page 61

• Manufacturer Part Number: SI3225-G-GQ
• Description: IC PROSLIC/CODEC DUAL 64TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: ProSLIC®r

Specifications of SI3225-G-GQ

• Function: Subscriber Line Interface Concept (SLIC), CODEC
• Interface: GCI, PCM, SPI
• Number Of Circuits: 2
• Voltage - Supply: 3.3V, 5V
• Current - Supply: 65mA
• Power (watts): 941mW
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 64-TQFP, 64-VQFP
• Includes: Battery Switching, BORSCHT Functions, DTMF Generation and Decoding, FSK Tone Generation, Modem and Fax Tone Detection
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Setting the linefeed register to the opposite polarity
immediately reverses (hard reversal) the line polarity.
For example, to transition from Forward Active mode to
Reverse Active mode changes LF[2:0] from 001 to 101.
Polarity reversal is accommodated in the OHT and
ground start modes. The POLREV bit is a read-only bit
that reflects if the device is in polarity reversal mode.
For smooth polarity reversal, set the PREN bit to 1 and
the RAMP bit to 0 or 1 depending on the desired ramp
rate
accomplished by toggling the linefeed register from
forward to reverse modes as desired.
(see
Parameter
Linefeed
Polarity Reversal Status
Wink Function
(Smooth transition to Voc=0V)
Smooth Polarity Reversal Enable
Smooth Polarity Reversal Ramp
Rate
Table 33).
V
-10
-20
-30
-40
-50
TIP/RING
0
0
Table 33. Register and RAM Locations used for Polarity Reversal
Set VOCZERO bit to 1
(V)
Figure 32. Wink Function with Programmable Ramp Rate
Polarity
10
20
reversal
2 V/125 µs slope
set by RAMP bit
30
See Table 18
Read only
1 = Ramp to 0 V
0 = Return to previous V
0 = Disabled
1 = Enabled
0 = 1 V/125 µs
1 = 2 V/125 µs
Programmable Range
is
Set VOCZERO bit to 0
then
40
Rev. 1.3
A wink function slowly ramps down the TIP-RING
voltage (V
VOC value (set in the VOC RAM location). This scheme
lights a message-waiting lamp in certain handsets. No
change to the linefeed register is necessary to enable
this function. Instead, the user sets the VOCZERO bit to
1 so that the TIP-RING voltage collapses to 0 V at the
rate programmed by the RAMP bit. Setting the
VOCZERO bit back to 0 returns the TIP-RING voltage
to its normal setting. With a software timer, the user can
automate the cadence of the wink function. Figure 32
illustrates the wink function.
50
Si3220/25 Si3200/02
60
OC
OC
) to 1 followed by a return to the original
Register/RAM
VOCZERO
70
POLREV
V
LF[2:0]
V
V
RAMP
PREN
cm
Bits
oc
ov
V
80
RING
V
V
BAT
TIP
Register/RAM
Time (ms)
Mnemonic
LINEFEED
POLREV
POLREV
POLREV
POLREV
61