XRT83SL314ES Exar, XRT83SL314ES Datasheet - Page 33

• Manufacturer Part Number: XRT83SL314ES
• Description: LIN Transceivers 14 CHT1/E1 LIUSH
• Manufacturer: Exar

Specifications of XRT83SL314ES

• Product Category: LIN Transceivers
• Rohs: yes

xr
14-CHANNEL T1/E1/J1 SHORT-HAUL LINE INTERFACE UNIT
Telecommunication system design requires signal integrity and reliability. When a T1/E1 primary line card has
a failure, it must be swapped with a backup line card while maintaining connectivity to a backplane without
losing data. System designers can achieve this by implementing common redundancy schemes with the
XRT83SL314 LIU. EXAR offers features that are tailored to redundancy applications while reducing the
number of components and providing system designers with solid reference designs.
RLOS and DMO
If an RLOS or DMO condition occurs, the XRT83SL314 reports the alarm to the individual status registers on a
per channel basis. However, for redundancy applications, an RLOS or DMO alarm can be used to initiate an
automatic switch to the back up card. For this application, two global pins RLOS and DMO are used to indicate
that one of the 14-channels has an RLOS or DMO condition.
Typical Redundancy Schemes
•
•
•
The 1:1 facility protection and 1+1 line protection have one backup card for every primary card. When using
1:1 or 1+1 redundancy, the backup card has its transmitters tri-stated and its receivers in high impedance. This
eliminates the need for external relays and provides one bill of materials for all interface modes of operation.
For 1+1 line protection, the receiver inputs on the backup card have the ability to monitor the line for bit errors
while in high impedance. The transmit and receive sections of the LIU device are described separately.
The transmitters on the backup card should be tri-stated. Select the appropriate impedance for the desired
mode of operation, T1/E1/J1. A 0.68uF capacitor is used in series with TTIP for blocking DC bias. See
Figure 24. for a simplified block diagram of the transmit section for a 1:1 and 1+1 redundancy.
F
The receivers on the backup card should be programmed for "High" impedance. Since there is no external
resistor in the circuit, the receivers on the backup card will not load down the line interface. This key design
feature eliminates the need for relays and provides one bill of materials for all interface modes of operation.
Select the impedance for the desired mode of operation, T1/E1/J1. To swap the primary card, set the backup
card to internal impedance, then the primary card to "High" impedance. See Figure 25. for a simplified block
diagram of the receive section for a 1:1 redundancy scheme.
3.3
3.3.1
3.3.2
3.3.3
IGURE
1:1 One backup card for every primary card (Facility Protection)
1+1 One backup card for every primary card (Line Protection)
·N+1 One backup card for N primary cards
24. S
Line Card Redundancy
1:1 and 1+1 Redundancy Without Relays
Transmit Interface with 1:1 and 1+1 Redundancy
Receive Interface with 1:1 and 1+1 Redundancy
IMPLIFIED
B
LOCK
Backplane Interface
D
IAGRAM OF THE
Internal Impedence
Backup Card
Internal Impedence
Primary Card
Tx
Tx
T
RANSMIT
0.68uF
0.68uF
30
XRT83SL314
XRT83SL314
I
NTERFACE FOR
1:2
1:2
T1/E1 Line
1:1
AND
1+1 R
EDUNDANCY
XRT83SL314
REV. 1.0.1