78P2351-IGTR/F Maxim Integrated Products, 78P2351-IGTR/F Datasheet - Page 11

• Manufacturer Part Number: 78P2351-IGTR/F
• Description: LINE INTERFACE UNIT 100-LQFP
• Manufacturer: Maxim Integrated Products

Specifications of 78P2351-IGTR/F

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Design Guidelines for TERIDIAN 78P235x LIUs
REFERENCE DESIGN WITH TRANSWITCH L4M (E4) MAPPER
For E4 applications, the L4M mapper from Transwitch is a very commonly used device. The Teridian 78P2351
can work with the L4M mapper seamlessly for such applications. The following block diagram displays how two
devices are inter-connected at the system level.
Notes:
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OPTICAL MEDIA INTERFACE
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media interface.
LOSS OF LOCK BEHAVIOR
After power-up or chip reset, the receiver LOL status bits (and pins) may be in an undefined state and report
incorrect status. To properly reset the Rx LOL detector, one must assert & de-assert the LOLOR bit (5) in the
signal control register during initialization. Use of receiver loss of lock detector is not recommended in HW (pin
control) operation. False Rx LOL assertion or toggling the LOLOR bit will not affect the integrity of the data path
or clock recovery.
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Since the Transwitch L4M provides a clock for the 78P2351, the 78P2351 should be set for parallel-slave
mode accordingly.
The Transwitch L4M is a 5V device and the 78P2351 is a 3.3V device. A 5V to 3.3V data buffer is needed to
translate the voltages between them
During L4M Line Loopback, configure the 78P2351 for Loop-timing parallel-slave mode.
The dual channel 78P2352 is not recommended for E4 applications due to the asynchronous nature of each
E4 signaling path.
Transwitch L4M
TXC-03456
E4 Mapper
Overhead Processor
SDH (STM1)
Loop filter
34.816MHz
VCXO
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Figure 12: Inter-connection Between Transwitch L4M and 78P2351
EXLOS
RXDn
RXCO
TXDn
TXC
Buffer
5V to
Data
3.3V
4-bit nibble
35MHz
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4-bit nibble
35MHz
POCK
PIxD
PICK
POxD
Div 2
LOS (active-high)
Serial 155Mbps LVPECL
(NRZ coding)
E4/STM1e LIU
TDK 78P2351
for detailed instructions on how to use the optical
E4 Line Interface
(75ohm coax)
Rev 2.1