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xr
XRT94L33
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
Rev.1.2.0.
33
AF17
TXDS3CLK_2
TXE3CLK_2
I
TTL
Transmit DS3/E3 Reference Clock Input – Channel 2 (Not
used for Mapper Applications):
The exact manner in which the user should handle this input
pin depends upon whether Channel 2 has been configured to
operate in the Mapper Mode or in the ATM UNI/PPP Mode.
If Channel 2 is configured to operate in the Mapper Mode:
If Channel 2 has been configured to operate in the Mapper
Mode, then this input pin supports no function, and should,
therefore, be connected to GND.
If Channel 2 is configured to operate in the ATM UNI/PPP
Mode:
If Channel 2 (within the XRT94L33) has been configured to
operate in the ATM UNI/PPP Mode, then this input pin will
function as the timing reference clock signal for the Transmit
STS-1/DS3/E3 Framer block circuitry, provided that Channel 2
has been configured to operate in the Local Timing Mode.
If Channel 2 has been configured to operate in the DS3 Mode,
then the user is expected to apply a 44.736MHz clock signal to
this input pin. Likewise, if Channel 2 has been configured to
operate in the E3 Mode, then the user is expected to apply a
34.368MHz clock signal to this input pin.
Note:
For more information on using the XRT94L33 for
ATM UNI/PPP applications, the user should consult
the
XRT94L33
1-Channel
STS-3c/3-Channel
DS3/E3/STS-1 ATM UNI/PPP Data Sheet.
B11
A22
AD16
TxOHClk_0
TxOHClk_1
TxOHClk_2
O
CMOS
Transmit Overhead Clock Output:
This output pin functions as the “Transmit Overhead Clock”
output for the transmit system side interface when the
XRT94L33 is configured to operate in STS-1/DS3/E3 mode,
however, it functions as the “Transmit STS-1 Overhead” clock
output when the device is configured to operate in the STS-1
mode.
When configured to operate in DS3/E3 mode:
This output pin functions as the “Transmit Overhead Data
Input Interface clock signal. If the user enables the “Transmit
Overhead Data Input Interface” block by asserting the
“TxOHIns” input pin, then the Transmit Overhead Data Input
Interface block will sample and latch the data (residing on the
“TxOH_n” input pin) upon the falling edge of this signal.
When configured to operate in STS-1 mode:
These output pins, along with “TxOH_n”, “TxOHEnable_n”,
“TxOHIns_n” and “TxOHFrame” function as the “Transmit Path
Overhead (TxOH) Input Port”.
The “TxOHFrame” and “TxOHEnable” output pins are updated
upon the falling edge this clock output signal.
The
“TxOHIns_n” input pins and the data residing on the “TxOH_n”
input pins are sampled upon the falling edge of this clock
signal.