IDT728980 Datasheet, PDF (1/10 Pages) Integrated Device Technology – TIME SLOT INTERCHANGE DIGITAL SWITCH 256 x 256

TIME SLOT INTERCHANGE
DIGITAL SWITCH
256 x 256
IDT728980
.EATURES:
• 256 x 256 channel non-blocking switch
• Serial Telecom Bus Compatible (ST-BUS^®)
• 8 RX inputs—32 channels at 64 Kbit/s per serial line
• 8 TX output—32 channels at 64 Kbit/s per serial line
• Three-state serial outputs
• Microprocessor Interface (8-bit data bus)
• 5V Power Supply
• Available in 44-pin Plastic Leaded Chip Carrier (PLCC), 40-pin
Plastic Dip (P-DIP) and 44-pin Plastic Quad Flatpack (PQFP)
• Operating Temperature Range -40°C to +85°C
DESCRIPTION:
The IDT728980 is a ST-BUS^® compatible digital switch controlled by a
microprocessor. The IDT728980 can handle as many as 256, 64 Kbit/s input
and output channels. Those 256 channels are divided into 8 serial inputs and
outputs, each of which consists of 32 channels (64 Kbit/s per channel) to form
a multiplexed 2.048 Mb/s stream.
.UNCTIONAL DESCRIPTION
A functional block diagram of the IDT728980 device is shown on below. The
serial ST-BUS^® streams operate continuously at 2.048 Mb/s and are arranged
in 125µs wide frames each containing 32, 8-bit channels. Eight input (RX0-7)
and eight output (TX0-7) serial streams are provided in the IDT728980 device
allowing a complete 256 x 256 channel non-blocking switch matrix to be
constructed. The serial interface clock (C4i) for the device is 4.096 MHz.
The received serial data is internally converted to a parallel format by the on
chip serial-to-parallel converters and stored sequentially in a 256-position Data
Memory. By using an internal counter that is reset by the input 8 KHz frame pulse,
F0i, the incoming serial data streams can be framed and sequentially addressed.
Data to be output on the serial streams may come from two sources: Data
Memory or Connection Memory. The Connection Memory is 16 bits wide and
.UNCTIONAL BLOCK DIAGRAM
C4i F0i VCC GND
ODE
RX0
Timing
TX0
RX1
Unit
Output MUX
TX1
RX2
Receive
RX3
Serial Data
Data
Streams
Memory
RX4
TX2
Transmit
Serial Data
TX3
Streams
TX4
RX5
Control Register
Connection
TX5
RX6
Memory
TX6
RX7
Microprocessor Interface
TX7
DS CS R/W A0/ _DTA D0/
A5
D7
CCO
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 2001 Integrated Device Technology, Inc.
JANUARY 2001
DSC-5706/1