DS26303LN-75+ Maxim Integrated Products, DS26303LN-75+ Datasheet - Page 60

IC LIU E1/T1/J1 3.3V 144-ELQFP

DS26303LN-75+

Manufacturer Part Number
DS26303LN-75+
Description
IC LIU E1/T1/J1 3.3V 144-ELQFP
Manufacturer
Maxim Integrated Products
Type
Line Interface Units (LIUs)r
Datasheet

Specifications of DS26303LN-75+

Number Of Drivers/receivers
8/8
Protocol
T1/E1/J1
Voltage - Supply
3.135 V ~ 3.465 V
Mounting Type
Surface Mount
Package / Case
144-LQFP Exposed Pad, 144-eLQFP, 144-HLQFP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
6.4.3 Loss of Signal
The DS26303 uses both the digital and analog loss-detection method in compliance with the latest ANSI T1.231 for
T1/J1 and ITU-T G.775 (LASCS.LASCSn reset) or ETS 300 233 (LASCS.LASCSn set) for E1 mode of operation.
LOS is detected if the receiver level falls bellow a threshold analog voltage for a certain duration. Alternatively, this
can be termed as having received zeros for a certain duration. The signal level and timing duration are defined in
accordance with the T1.231, G.775, or ETS 300 233 specifications.
The loss-detection thresholds are based on cable loss of 15dB for both T1 and E1 mode. RCLKn is replaced by
MCLK when the receiver detects a loss of signal. If the AISEL bit is set in the
bit is set, the RPOSn/RNEGn data is replaced by an all-ones signal upon receiving an LOS to indicate AIS to the
downstream device. The loss state is exited when the receiver detects a certain number of ones density at a higher
signal level than the loss-detection level. The loss-detection-signal level and loss-reset-signal level are defined with
a hysteresis to prevent the receiver from bouncing between LOS and no-LOS states.
The following table outlines the specifications governing the loss function.
Table 6-5. Loss Criteria T1.231, G.775, and ETS 300 233 Specifications
Loss
Detection
Loss Reset
6.4.3.1
Loss is detected if the received signal level is typically less than 200mV for duration of 192 bit periods. LOS is reset
if the all of the following criteria are met:
6.4.3.2
LOS is detected if the received signal level is typically less than 200mV for a continuous duration of 192 bit periods.
LOS is reset if the receive signal level is typically greater than 300mV for a duration of 192 bit periods.
6.4.3.3
LOS is detected if the received signal level is typically less than 200mV for a continuous duration of 2048 (1ms) bit
periods. LOS is reset if the receive signal level is typically greater than 300mV for a duration of 192 bit periods.
6.4.4 AIS
Table 6-6
The registers related to the AIS detection are shown in
CRITERIA
ANSI T1.231 for T1 and J1 Modes
ITU-T G.775 for E1 Modes
ETS 300 233 for E1 Modes
outlines the DS26303 AIS-related specifications.
24 or more 1s are detected in a 192-bit period with a detection threshold of 300mV measured
at RTIPn and RRINGn.
During the 192 bits less than 100 consecutive zeros are detected.
Eight consecutive 0s are not detected if B8ZS is set.
No pulses are detected for 175
±75 bits.
Loss is terminated if a duration of
12.5% ones are detected over
duration of 175 ±75 bits. Loss is
not terminated if eight consecutive
0s are found if B8ZS encoding is
used. If B8ZS is not used, loss is
not terminated if 100 consecutive
pulses are 0.
ANSI T1.231
DS26303: 3.3V, T1/E1/J1, Short-Haul, Octal Line Interface Unit
60 of 101
No pulses are detected for
duration of 10 to 255 bit
periods.
The incoming signal has
transitions for duration of 10
to 255 bit periods.
Table
STANDARD
Table 6-7
ITU-T G.775
6-8.
states the AIS functionality in the DS26303.
GC
register, or if the IAISEL.ILAISE
No pulses are detected for a
duration of 2048 bit periods or
1ms,
Loss reset criteria is not
defined.
ETS 300 233

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