TDM Switch Platform Is Ripe With Features

Said to integrate features previously available only on high-bandwidth devices, the three-chip ZLTM50010/11/12 series TDM switches provide 512 channels and is designed for use in small to medium sized multi-service access platforms. The ZL50010 switch integrates programmable features that include per-stream data rate conversion and input/output synchronization with digital PLL circuitry. This allows the device to replace up to five devices. Each chip in the series processes channels at the digital-signal-0 level to allow non-blocking 512 x 512 channel connections in Nx64 Kb/s configurations. System size can be reduced by using a single ZL50010 or ZL50011 to replace 256 x 256-channel TDM switches and one digital PLL. The TDM input and output streams operate at data rates of 2.048, 4.096, or 8.192 Mb/s, and a data rate selection feature employs patent-pending circuit techniques that reduce on-chip memory requirements and minimize die size. The ZL50010 and ZL50011 include digital PLLs that meet network synchronization requirements as per GR-1244-CORE standard for Stratum 4E clocks. Input clocking reference signals for both PLLs operate at 2.048 MHz, 1.544 MHz, or 8 kHz. The PLL in the ZL50010 uses two reference clocks and includes holdover capabilities. Available in 24 mm x 24 mm, 160-pin LQFPs and 13 mm x 13 mm, 144-pin BGAs, the ICs cost $11 to $19.50 each, with the exact price depending on the device and package. ZARLINK SEMICONDUCTOR, Ottawa, Canada. (613) 270-7115.