STM7E1 7 E1 channels switch array Features Main switches max. R less than 2 ON Provides 7 auxiliary switches with R < 75 ON 6 V amplitude of analog input signal PP Digital inputs are TTL levels compatible Applications TQFP64 Telecom infrastructure Relays replacement E1/T1 signals routing Loopback hardware diagnostic loop, while if is closed, the main port RX and Line card TX access is connected between each other to form a local loop. Negative rail signal routing The spare port is only used for test purpose on the system board while the main port is the Description communication channel. Consequently, a The STM7E1A consists of 7 identical ISDN E1 switching from the main port to the spare port channels, each channel corresponding to 4 main occurs very rarely (< 10 times a day). low-resistant switches (a and b) and 2 auxiliary The power supplies of the chip need to be de switches (c and d). The switches positions in all coupled properly. This means that at least one the channels are identical and controlled by a external capacitor C1 must be connected in unique control resource driven by the digital between GND and VPOS, one external capacitor inputs Lm, Ls and Sc. C2 between GND and VNEG, and one external In each channel, the TX and RX lines can be capacitor C3 between each pair of VNEG and switched between a main port or a spare port by VPOS. the main switches: if both switches are closed and both switches are open, the main port is connected to the line, while if both switches are open and bothb 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 is closed, the spare port RX and TX access is connected between each other to form a local Table 1. Device summary Order code Temperature range Package Packaging STM7E1AR -40 to 85 C TQFP64 (tape and reel) 1000 parts per reel October 2009 Doc ID 9226 Rev 4 1/16 www.st.com 16Contents STM7E1 Contents 1 Application circuit . 3 1.1 Test mode description (mode = 0, test = 1) 5 2 Pin configuration . 6 3 Maximum ratings 9 4 Package mechanical data 12 5 Revision history . 15 2/16 Doc ID 9226 Rev 4