XRT5794ES Datasheet, PDF (1/11 Pages) Exar Corporation – Evaluation System

XRT5794ES
Evaluation
System
GENERAL DESCRIPTION
The XR-T5794 demo board is a 4.75” x 9.75”
double-sided circuit card that provides the support
circuitry necessary for a comprhensive evaluation of the
XR-T5794 CMOS Quad E1 Line Interface IC. three
board-mounted DIP switches allow complete testing of all
loop back, monitor, and transmitter power-down features.
The demo board is normally supplied configured for 120W
balanced E1 operation. However, the information
contianed in this manual enables the user to modify the
hardware for E1 unbalanced 75W cable service, or T1
balanced 100W use.
BOARD OPERATION
Figures 1, 2 and Table 2 are the board component layout,
circuit diagram, and parts list respectively. The Demo
Board uses the same pin function and signal names as
the XR-T5794 data sheet. This user’s manual is designed
to be used in conjuction with the XR-T5794 data sheet.
The following description if for a demo board set up for
balanced 120 W E1 use. It also applies to the other modes
of operation if the appropriate impedence, cable type, and
signal source changes are made.
Power Requirements
Power connections are made to banana jacks located in
the upper left hand corner of the board. Power supply
requirements are:
V_DD = +5.0 V ±5% at 850 mA maximum
V_SS = - 5.0 V ±5% at 850 mA minimum
Line-Side Signals
Receiver signal inputs are labeled RXIN1 through RXIN4
for the four channels. The connectors supplied for
balanced 120W operation are one quarter inch, 3-circuit
audio type jacks. Equipment connections should be made
with shielded twisted pair patch cords. The signal applied
to any inputs must be a CCITT G.703 compliant pulse that
may be attenuated by a twisted-pair cable. The XR-T5794
exceeds G.703 maximum cable loss of requirement of 6.0
dB at 1.024 MHz.
Similarly, transmitter outputs are labeleds TXOUT1
through TXOUT4 for the four channels. The monitor
channel output is labeled MONOUT. Connector types
and connection methods are identical to those specified
above for the recieve side. The transmitter output, when
terminated by a 120W resistor, is a pulse meeting the
G.703 template requirements. During demo board
evaluation, all ransmitters, including the monitor channel,
that are not powered down should be connected to either
a properly terminated cable, a piece of test equipment
contianing a termination, or a 120W load resistor.
Equipment-Side Signal Connections
For convenience, access to the logic-level
equipment-side signals is provided by two groups of turret
terminals and also by two ribbon cable connectors. The
terminals are convient for simple tests while the ribbon
cable connectors reduce the amount of wiring necessary
to connect the entire equipment side of the demo board to
customer equipment.
Header P1 and a group of terminals that provide channel
1 and 2 I/O are located below the XR-T5794. For
channels 3 and 4, P2 and a second group of pins are
located above the XR-T5794. P1 and P2 are dual-row 26
pin headers with only the odd-nimbered pins used to carry
signals. Even-numbered pins are grounded to minimize
ribbon cable crosstalk. Pin 13 is also grounded to provide
isolation between the transmit and receive directions.
Rev. 2.00
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