IDT72V8988 Datasheet, PDF (1/14 Pages) Integrated Device Technology – 3.3 VOLT TIME SLOT INTERCHANGE DIGITAL SWITCH 128 x 128

3.3 VOLT TIME SLOT INTERCHANGE
DIGITAL SWITCH
128 x 128
IDT72V8988
FEATURES:
• 128 x 128 channel non-blocking switch
• Automatic signal identification (ST-BUS^®, GCI)
• 4 RX inputs—32 channels at 64 Kbit/s per serial line
• 4 TX outputs—32 channels at 64 Kbit/s per serial line
• Three-state serial outputs
• Microprocessor Interface (8-bit data bus)
• Frame Integrity for data applications
• 3.3V Power Supply
• Available in 44-pin Plastic Leaded Chip Carrier (PLCC), and
44-pin Plastic Quad Flatpack (PQFP)
• Operating Temperature Range -40°C to +85°C
• 3.3V I/O with 5V Tolerant Inputs
DESCRIPTION:
The IDT72V8988 is an ST-BUS^®/GCI compatible digital switch controlled
by a microprocessor. The IDT72V8988 can handle as many as 128, 64 Kbit/s
input and output channels. Those 128 channels are divided into 4 serial inputs
and outputs, each of which consists of 32 channels. The IDT72V8988 provides
per-channel variable or constant throughput delay modes and microprocessor
read and write access to individual channels. As an important function of a digital
switch is to maintain sequence integrity and minimize throughput delay, the
IDT72V8988 is an ideal solution for most switching needs.
FUNCTIONAL DESCRIPTION
Frame sequence, constant throughput delay, and guaranteed minimum
delay are high priority requirements in today’s integrated data and multimedia
networks. The IDT72V8988 provides these functions on a per-channel basis
using a standard microprocessor control interface. Each of the four serial lines
is designed to switch 64 Kbit/s PCM or N x 64 Kbit/s data.
In Processor Mode, the microprocessor can access the input and output time
slots to control other devices such as ISDN transceivers and trunk interfaces.
Supporting both GCI and ST-BUS^® formats, IDT72V8988 has incorporated an
internal circuit to automatically identify the polarity and format of the frame
synchronization.
A functional block diagram of the IDT72V8988 device is shown on page 1.
The serial streams operate continuously at 2.048 Mb/s and are arranged in
125µs wide frames each containing 32, 8-bit channels. Four input (RX0-3) and
FUNCTIONAL BLOCK DIAGRAM
C4i F0i VCC GND
ODE
Timing
Unit
Output MUX
RX0
Receive
RX1
Serial Data
Data
RX2
Streams
Memory
RX3
Control Register
TX0
Transmit
Serial Data
TX1
Streams
TX2
Connection
TX3
Memory
Microprocessor Interface
DS CS R/W A0/ _DTA D0/
A5
D7
5704 drw01
IDT and the IDT logo are registered trademarks of Integrated Device Technology, Inc. The ST-BUS^ is a trademark of Mitel Corp.
1
 2003 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice.
AUGUST 2003
DSC-5704/5