xrt75r12 Exar Corporation, xrt75r12 Datasheet - Page 6

• Manufacturer Part Number: xrt75r12
• Description: Twelve Channel E3/ds3/sts-1 Line Interface Unit With Jitter
• Manufacturer: Exar Corporation

XRT75R12
TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR
PIN DESCRIPTIONS (
SYSTEM-SIDE TRANSMIT INPUT AND TRANSMIT CONTROL PINS
AA22
AA25
AB24
AA23
AA26
P
H22
G26
AA2
AA5
G25
AA1
AA4
AB3
F22
Y23
E23
J22
G1
H5
G2
P4
Y4
F5
E4
J5
IN
#
S
TxPOS10
TxPOS11
IGNAL
TxCLK10
TxCLK11
TxPOS0
TxPOS1
TxPOS2
TxPOS3
TxPOS4
TxPOS5
TxPOS6
TxPOS7
TxPOS8
TxPOS9
TxCLK0
TxCLK1
TxCLK2
TxCLK3
TxCLK4
TxCLK5
TxCLK6
TxCLK7
TxCLK8
TxCLK9
TxON
N
AME
BY FUNCTION
T
YPE
I
I
I
Transmit On/Off Input
Upon power up, the transmitters are powered on. Turning the transmitters
On or Off is selected through the microprocessor interface by programming
the appropriate channel register if this pin is pulled "High". If the TxON pin
is pulled "Low", all 12 transmitters are powered off.
N
Transmit Clock Input
These input pins have three functions:
•
•
•
N
Transmit Positive Data Input
The function of these digitial input pins depends upon whether the corre-
sponding channel has been configured to operate in the Single-Rail or
Dual-Rail Mode.
Single Rail Mode - Transmit Data Input
Operating in the Single-Rail Mode; all transmit input data will be serially
applied to this input pin. This signal will be latched into the Transmit Sec-
tion circuitry on the active edge of the TxCLK_n signal.
The Transmit Section of the LIU IC will then encode this data into either the
B3ZS line code (for DS3 and STS-1 applications) or the HDB3 line code
(for E3 applications).
Dual Rail Mode - Transmit Positive Data Input
In the Dual-Rail Mode, the user should apply a pulse to this input pin when
a positive-polarity pulse is to be transmitted onto the line. This signal will
be latched into the Transmit Section circuitry upon the active edge of the
TxCLK_n signal,.
The Transmit Section of the LIU IC will NOT encode this data into either the
B3ZS or HDB3 line codes. If the user configures the LIU IC to operate in
the Dual-Rail Mode, B3ZS/HDB3 encoding must have already been done
prior to this input.
)
OTE
OTE
They function as the timing source for the Transmit Section of the
corresponding channel within the XRT75R12.
They are used by the Transmit Section of the LIU IC to sample the
corresponding TxPOS_n and TxNEG_n input pins.
They are used to clock the PRBS generator
: TxON is ideal for redundancy applications. See the R
: The user is expected to supply a 44.736MHz ± 20ppm clock signal
section of this datasheet for more details. Internally pulled "High".
(for DS3 applications), 34.368MHz ± 20 ppm clock signal (for E3
applications) or a 51.84MHz ± 4.6ppm clock signal (for STS-1,
Stratum 3E or better applications).
3
D
ESCRIPTION
3
Technology
REV. 1.0.4