Rudolf Koch

A 1.544 Mb/s CMOS Line Driver for 22.8 Ohm Load

A CMOS line driver for the ISDN Primary Access Transceiver IPAT is presented. Operating in bridge configuration a driver pair delivers. 7.2 Vpp output voltage into a differential load of 22.8¿ at a data rate of 1.544 Mb/s (T1 application), using a single 5V supply voltage. The main feature of the single drivers is a control unit which stabilizes the quiescent current in the output stage at 20mA, while the peak output current is 180mA (T1). The circuit can also be logically configurated to deliver 6 Vpp into a differential load of 60¿ with a quiescent current of 7mA and a data rate of 2.048 Mb/s (CEPT application). Because of its large output transistors, the driver pair occupies an area of 6500 square mils in a 2¿m p-well technology.