3222/3223-DB1 Silicon Laboratories Inc, 3222/3223-DB1 Datasheet - Page 40

• Manufacturer Part Number: 3222/3223-DB1
• Description: EVAL BOARD FOR IA3222/3223
• Manufacturer: Silicon Laboratories Inc
• Series: EZ DAA™r

Specifications of 3222/3223-DB1

• Main Purpose: Telecom, Data Acquisition Arrangement (DAA)
• Embedded: Yes, FPGA / CPLD
• Utilized Ic / Part: IA3222, IA3223
• Primary Attributes: -
• Secondary Attributes: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

IA3222/23
7.4. Threshold Register
7.5. Line Status Register (Read Only)*
*Note: Writing any value to this register will reset all registers to their default values.
40
*Note: The parallel-pickup threshold must be selected based on line usage and history. Depending on the application,
Notes:
LP [Note 1]
Mnemonic
LTH1
RTH1
1. This bit is multiplexed to a digital output pin of the IA3223A.
2. In the on-hook state, LACT will become high if the line voltage change is at least 10 to 20 V in either direction.
LACT
RNG
PPU
0
0
1
1
LIU
0
0
1
1
LD
selecting too sensitive a threshold may falsely detect a parallel pickup in the presence of large signals. Setting 0 or 1 is
recommended for voice applications. Modem applications, where transmitted levels and frequency envelopes are well
controlled, may benefit from using a more sensitive setting. Refer to Figure 17, which indicates the sensitivity of the
detection circuit for signals of different frequencies for various settings. Note that the “high” headroom setting,
(because of the reduced receiver gain), reduces the sensitivity of the parallel-pickup function by 3 dB. Each setting is
approximately twice as sensitive as the previous setting.
1
1
1
1
2
LTH0
RTH0
Parallel pickup
0
1
0
1
0
1
0
1
Line polarity
Line activity
Line In Use
Ring signal
Definition
Line Drop
Line-disconnect detection (~2.5 V)
No-Detection Ring Threshold (Vrms)
Line-in-Use Threshold (VDC)
On hook and off
22.5 ±7.5 V (reset state)
Applicability
On hook
On hook
Off hook
On hook
Off hook
Off hook
hook
10 (reset state)
30 ±10 V
15 ±5 V
12.5
15
20
Rev. 5.0
No change in line-in-use sta-
Voltage below ring threshold
Voltage above LIU threshold
Status When Bit is Low
No parallel-pickup event
No loop-current drop
Line reversed
Line active
tus
0: least sensitive (reset state)
Parallel-Pickup Threshold*
Ring Threshold (Vrms)
3: most sensitive
Change in line-in-use status
Voltage above ring thresh-
Voltage below LIU thresh-
Status When Bit is High
Line disconnected or line
20 (reset state)
Parallel-pickup event
Loop-current drop
1
2
Line direct
25
30
40
fault
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