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REV: 042204
Note:
Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here:
www.maxim-ic.com/errata
.
GENERAL DESCRIPTION
The DS21Q55 is a quad software-selectable T1, E1,
or J1 MCM device for short-haul and long-haul
applications. Each port is composed of a line
interface unit (LIU), framer, HDLC controllers, and a
TDM backplane interface, and is controlled by an
8-bit parallel port configured for Intel or Motorola
bus operations. The DS21Q55 is software compatible
with the DS2155 single-chip transceiver. It is pin
compatible with the DS21Qx5y family of products.
Each LIU is composed of transmit and receive
interfaces and a jitter attenuator. The transmit
interface is responsible for generating the necessary
waveshapes for driving the network and providing
the correct source impedance depending on the type
of media used. T1 waveform generation includes
DSX-1 line build-outs as well as CSU line build-outs
of -7.5dB, -15dB, and -22.5dB. E1 waveform
generation includes G.703 waveshapes for both 75
coax and 120 twisted cables. The receive interface
provides network termination and recovers clock and
data from the network.
APPLICATIONS
Routers
Channel Service Units (CSUs)
Data Service Units (DSUs)
Muxes
Switches
Channel Banks
T1/E1 Test Equipment
DSL Add/Drop Multiplexers
FEATURES
Complete T1/DS1/ISDN-PRI/J1 Transceiver
Functionality
Complete E1 (CEPT) PCM-30/ISDN-PRI
Transceiver Functionality
Long-Haul and Short-Haul Line Interface for
Clock/Data Recovery and Waveshaping
CMI Coder/Decoder for Optical I/F
Crystal-Less Jitter Attenuator
Fully Independent Transmit and Receive
Functionality
Dual HDLC Controllers
Programmable BERT Generator and Detector
Internal Software-Selectable Receive and
Transmit-Side Termination Resistors for
75 /100 /120 T1 and E1 Interfaces
Dual Two-Frame Elastic-Store Slip Buffers that
Connect to Asynchronous Backplanes Up to
16.384MHz
16.384MHz, 8.192MHz, 4.096MHz, or
2.048MHz Clock Output Synthesized to
Recovered Network Clock
ORDERING INFORMATION
PART
TEMP RANGE
PIN-PACKAGE
256 BGA
(27mm x 27mm)
DS21Q55
0°C to +70°C
DS21Q55N
-40°C to +85°C
256 BGA
(27mm x 27mm)
Pin Configurations appear in Section
.