Description
The PM8620 NSE-20G is a monolithic CMOS integrated circuit packaged in a 480 ball UBGA that performs DS0 and above granularity space switching on 32 SBI336 streams carried as serial SBI336S in 8B/10B coding over LVDS at 777.6 Mbit/s. The NSE-20G also performs VT1.5/VT2 and above granularity switching on 32 STS-12/STM-4 SONET/SDH streams, carried as Serial TelecomBus signals in 8B/10B coding over LVDS at 777.6 Mbit/s.

Features
The Narrowband Switch Element 20G (NSE-20G):
• Implements a Scaleable Bandwidth Interconnect (SBI™) DS0 granularity Space switch.
• Implements a SONET/SDH VT1.5/VT2/TU11/TU12 granularity Space switch for the serial 777.6 MHz LVDS TelecomBus.
• With the allied SBS or SBS-lite device, implements a DS0 granularity Memory-Space Memory switch.
• Supports 32 STS-12 equivalent serial ports via 777.6 MHz, 8B/10B encoded LVDS links (each port can be either Serial TelecomBus or Serial SBI336S)
• When configured for SBI mode, switches DS0 or N*DS0 for all T1 and E1 tributaries and aggregate columns for switching T1, E1, TVT1.5, TVT2, DS3 and E3 tributaries.
• When configured for the serial 777.6 MHz TelecomBus interface, switches any SONET/SDH virtual tributary or tributary unit up to STS-1.
• Supports switching of arbitrary non-standard octet aggregates.
• Supports unicast, multicast, and broadcast for all switching modes.
• Provides 20 Gbit/s (258,048 DS0s, 10,752 T1s/VT1.5s, 8,064 E1s/VT2s, 384 DS3s/E3s) switching.
• Works with SBS devices that support up to four 19.44 MHz SBI buses or one 77.76 MHz SBI336 bus that communicates with PMC-Sierra’s SBI device family. Alternatively, the SBS and SBS-lite devices support up to four 19.44 MHz STS-3 TelecomBuses or one 77.76 MHz STS-12 TelecomBus for connection with PMC-Sierra’s SPECTRA™ family of devices.
• Can be combined in applications with PMC-Sierra’s CHESS™ Set devices (PM5374 TSE and PM5307 TBS).
• Supports a microprocessor interface which is used to configure/control the NSE, to make DS0-granularity switch settings.
• Supports clean error checked 8 Mbit/s full-duplex, in-band communications channels from the NSE’s attached microprocessor to the attached microprocessors of each of the 32 attached SBS336S devices. This channel is used to initialize and control the SBSs, or other such devices, and to implement call-establishment set-up changes.
• Supports JTAG for all non-LVDS signals.
• Requires dual power supplies at 1.8 V and 3.3 V.
• Packaged as a 480 ball UBGA.
• In conjunction with the SBS or SBS-lite, supports “1+1” and “1:N” fabric redundancy.

Applications
The PM8620 Narrowband Switch Element (NSE) supports a variety of flexible Layer 1 and Layer 2 architectures in combination with the following PMC-Sierra devices:
• PM8610 SBS and PM8611 SBS-lite (SBI Serializer and Memory switching stage)
• SBI bus devices (PM8315 TEMUX™/PM5365 TEMAP, FREEDM™ devices, S/UNI®-IMA devices, AAL1gator™ devices, and other future devices)
• CHESS chip set devices (PM5374 TSE, PM5307 TBS, PM5315 SPECTRA™-2488, and PM7390 S/UNI®-MACH48) These architectures include:
• T1/E1 SONET Add/Drop Multiplexers (ADMs)
• TDM ASAP applications
• PHY cards with DS0 (and above) level switching
• PSTN replacement switching cores, as part of any-service-any-port applications • Voice Gateways