DS26521LN+ Maxim Integrated Products, DS26521LN+ Datasheet - Page 74

• Manufacturer Part Number: DS26521LN+
• Description: IC TXRX T1/E1/J1 64-LQFP
• Manufacturer: Maxim Integrated Products
• Type: Line Interface Units (LIUs)r

Specifications of DS26521LN+

• Number Of Drivers/receivers: 1/1
• Protocol: T1/E1/J1
• Voltage - Supply: 3.135 V ~ 3.465 V
• Mounting Type: Surface Mount
• Package / Case: 64-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 8-20. Typical Monitor Application
8.11.3.4
The DS26521 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, or ETS 300 233 for E1 mode of operation.
Loss of signal (LOS) is detected if the receiver level falls below a threshold analog voltage for certain duration.
Alternatively, this can be termed as having received “0s” for a certain duration. The signal level and timing duration
are defined in accordance with the ANSI T1.231, ITU-T G.775, or ETS 300 233 specifications.
For short-haul mode, the loss-detection thresholds are based on cable loss of 12dB to 18dB for both T1/J1 and E1
modes. The loss thresholds are selectable based on
is based on cable loss of 30dB to 38dB for T1/J1 and 30dB to 45dB for E1 mode. Note there is no explicit bit called
short-haul mode selection. Loss declaration level is set at 3dB lower that the maximum sensitivity setting
programmed in
The loss state is exited when the receiver detects a certain ones density at the maximum sensitivity level or higher,
which is 3dB higher than the loss-detection level. The loss-detection signal level and loss-reset signal level are
defined with hysteresis to prevent the receiver from bouncing between “LOS” and “no LOS” states.
outlines the specifications governing the loss function.
Table 8-33. ANSI T1.231, ITU-T G.775, and ETS 300 233 Loss Criteria Specifications
Loss Reset
CRITERIA
Detection
Loss
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 8
consecutive zeros are found if
B8ZS encoding is used. If
B8ZS is not used, loss is not
terminated if 100 consecutive
pulses are zero.
Table
Loss of Signal (LOS)
T1/E1 LINE
9-19.
ANSI T1.231
Rm
MONITOR
PORT JACK
Rm
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.
PRIMARY
T1/E1 TERMINATING
DEVICE
74 of 258
Table
STANDARD
ITU-T G.775
9-19. For long-haul mode, the LOS detection threshold
X
F
M
R
SECONDARY T1/E1
TERMINATING
DEVICE
Rt
DS26521 Single T1/E1/J1 Transceiver
DS26521
No pulses are detected for a
duration of 2048-bit periods or
1ms.
Loss reset criteria are not
defined.
ETS 300 233
Table 8-33