XRT83L30 Datasheet, PDF (28/78 Pages) Exar Corporation – SINGLE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR

XRT83L30
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ONE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR
REV. P1.3.0
PRELIMINARY
DRIVER FAILURE MONITOR (DMO)
The driver monitor circuit is used to detect transmit driver failure by monitoring the activities at TTIP and
TRING. Driver failure may be caused by a short circuit in the primary transformer or system problems at the
transmit input. If the transmitter has no output for more than 128 clock cycles, the corresponding DMO pin goes
“High” and remains “High” until a valid transmit pulse is detected. In Host mode, the failure of the transmit
channel is reported in the corresponding interface bit. If the DMOIE bit is also enabled, any transition on the
DMO interface bit will generate an interrupt. The driver failure monitor is supported in both Hardware and Host
modes.
TRANSMIT PULSE SHAPER & LINE BUILD OUT (LBO) CIRCUIT
The transmit pulse shaper circuit uses the high speed clock from the Master timing generator to control the
shape and width of the transmitted pulse. The internal high-speed timing generator eliminates the need for a
tightly controlled transmit clock (TCLK) duty cycle. With the jitter attenuator not in the transmit path, the
transmit output will generate no more than 0.025Unit Interval (UI) peak-to-peak jitter. In Hardware mode, the
state of the EQC[4:0] pins determine the transmit pulse shape. In Host mode transmit pulse shape can be
controlled using the interface bits EQC[4:0]. The chip supports five fixed transmit pulse settings for T1 Short-
haul applications plus a fully programmable waveform generator for arbitrary transmit output pulse shapes.
Transmit Line Build-Outs for T1 long-haul application are supported from 0dB to -22.5dB in three 7.5dB steps.
The choice of the transmit pulse shape and LBO under the control of the interface bits are summarized in
Table 5. For CSU LBO transmit pulse design information, refer to ANSI T1.403-1993 Network-to-Customer
Installation specification, Annex-E.
NOTE: EQC[4:0] determine the T1/E1 operating mode of the XRT83L30. When EQC4 = “1” and EQC3 = “1”, the XRT83L30
is in the E1 mode, otherwise it is in the T1/J1 mode.
EQC4
0
0
0
0
TABLE 5: RECEIVE EQUALIZER CONTROL AND TRANSMIT LINE BUILD-OUT SETTINGS
EQC3
0
0
0
0
EQC2
0
0
0
0
EQC1
0
0
1
1
EQC0
E1/T1 MODE & RECEIVE
SENSITIVITY
0
T1 Long Haul/36dB
1
T1 Long Haul/36dB
0
T1 Long Haul/36dB
1
T1 Long Haul/36dB
TRANSMIT LBO
0dB
-7.5dB
-15dB
-22.5dB
CABLE
100Ω/ TP
100Ω/ TP
100Ω/ TP
100Ω/ TP
CODING
B8ZS
B8ZS
B8ZS
B8ZS
0
0
1
0
0
T1 Long Haul/45dB
0dB
100Ω/ TP B8ZS
0
0
1
0
1
T1 Long Haul/45dB
-7.5dB
100Ω/ TP B8ZS
0
0
1
1
0
T1 Long Haul/45dB
-15dB
100Ω/ TP B8ZS
0
0
1
1
1
T1 Long Haul/45dB
-22.5dB
100Ω/ TP B8ZS
0
1
0
0
0
T1 Short Haul/15dB 0-133 ft./ 0.6dB 100Ω/ TP B8ZS
0
1
0
0
1
T1 Short Haul/15dB 133-266 ft./ 1.2dB 100Ω/ TP B8ZS
0
1
0
1
0
T1 Short Haul/15dB 266-399 ft./ 1.8dB 100Ω/ TP B8ZS
0
1
0
1
1
T1 Short Haul/15dB 399-533 ft./ 2.4dB 100Ω/ TP B8ZS
0
1
1
0
0
T1 Short Haul/15dB 533-655 ft./ 3.0dB 100Ω/ TP B8ZS
0
1
1
0
1
T1 Short Haul/15dB Arbitrary Pulse 100Ω/ TP B8ZS
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