XR-T7295

The XR-T7295 DS3/SONET STS-1 integrated line receiver is a fully integrated receive interface that terminates a bipolar DS3 (44.736Mbps) or Sonet STS-1 (51.84Mbps) signal transmitted over coaxial cable. (See Figure 13).

The device also provides the functions of receive equalization (optional), automatic-gain control (AGC), clock-recovery and data retiming, loss-of-signal and loss-of-frequency-lock detection. The digital system interface is dual-rail, with received positive and negative 1s appearing as unipolar digital signals on separate output leads. The on-chip equalizer is designed for cable distances of 0 to 450ft. from the cross-connect frame to the device. The receive input has a variable input sensitivity control, providing three different sensitivity settings, to adapt longer cables. High input sensitivity allows for significant amounts of flat loss within the system. Figure 1 shows the block diagram of the device.

The XR-T7295 device is manufactured using linear CMOS technology. The XR-T7295 is available in either a 20-pin plastic DIP or 20-pin plastic SOJ package for surface mounting.

Two versions of the chip are available, one is for either DS3 or STS-1 operation (the XR-T7295, this data sheet), and the other is for E3 operation (the XR-T7295E, refer to the XR-T7295E data sheet). Both versions are pincompatible.

For either DS3 or STS-1, an input reference clock at 44.736MHz or 51.84MHz provides the frequency reference for the device.