Suitable for ISDN applications worldwide, SGS-THOMSON Microelectronics' STLC5444 ISDN Quad Feeder integrated circuit reduces board size and complexity by integrating four digital telephone line feeder circuits on the same chip. In addition to the cost savings due to the components saved, the STLC5444 reduces the cost of ISDN board development because all of the feeding functions are integrated.
The STLC5444 is produced using high voltage mixed BCD technology, allowing operation with input voltages up to 120V. The only device on the market with 120V capability, it is able to meet all standards for "U" lines. Delivering up to 120mA to each line, it powers four ISDN "U" or "S" lines with individual control and status monitoring.
Integrated on the chip are the DMOS transistors that connect the line to the battery voltage, control logic and a microprocessor interface. Programmable current limiting protects the device against short circuits on any line and automatic thermal shutdown prevents damage to the circuit when the die temperature exceeds the safe maximum. Line monitoring and diagnostics are performed independently for each channel.
The STLC5444 is available in two packages: a 24-lead plastic DIP and a 44-lead plastic leaded chip carrier.
Bipolar-CMOS-DMOS (BCD) combines the high efficiency of DMOS power stages, the high density of CMOS circuits and the high precision of bipolar analog functions. The technology was pioneered by SGS-THOMSON in 1986 with the introduction of a 60V version based on 4um lithography. Subsequently the company has introduced 2.5um and 1.2um evolutions plus versions designed for 20V, 100V, 120V, 170V, 250V, 300V and 700V supplies. Today BCD technologies are used in the automotive, computer peripheral, telecom and video fields for applications ranging from motor driving to florescent lamp ballast.