1/10

December 2002

s

s

PROVIDES 7 AUXILIARY SWITCHES WITH

s

SIGNAL

s

DIGITAL INPUTS ARE TTL LEVELS

COMPATIBLE

DESCRIPTION

The STM7E1 consists in 7 identical ISDN E1

channels, each channel corresponding to 4 main

low-resistant switches (a and b) and 2 auxiliary

switches (c and d). The switches positions in all

the channels are identical and controlled by a

unique control resource driven by the digital inputs

Lm, Ls and Sc.

In each channel, the TX and RX lines can be

switched between a Main port or a Spare-port by

the main switches: if both "a" switches are closed

and both "b" switches are open, the Main port is

connected to the line, while if both "a" switches

are open and both "b' switches are closed, the

spare port is connected to the line.

The 2 auxiliary switches enable to close a local

loop between the TX and RX access of a port: if

"c" is closed, the Spare port RX and TX access is

connected between each other to form a local

loop, while if "d" is closed, the Main port RX and

TX access is connected between each other to

form a local loop.

The Spare port is only used for test purpose on the

system

board

while

the

Main

port

is

the

communication

channel.

Consequently,

a

switching from the Main port to the Spare port

occurs very rarely (<10 times a day).

The power supplies of the chip need to be de

coupled properly. This means that at least one

external capacitor C1 must be connected in

between GND and VPOS, one external capacitor

C2 between GND and VNEG, and one external

capacitor C3 between each pair of VNEG and

VPOS.

ORDERING CODES

Type

Temperature

Range

Package

Comments

STM7E1A

-40 to 85 °C

TQFP64 (Tray)

160 parts per Tray

STM7E1AR

-40 to 85 °C

TQFP64 (Tape & Reel)

1000 parts per reel

STM7E1A

7 E 1 CHANNELS SWITCH ARRAY

TQFP64