National Semiconductor Introduces New Crosspoint Switch with Transmit Pre-Emphasis and Receive Equalization

National Semiconductor DS25CP104

Category: Interface

The DS25CP104 is a 3.125 Gbps 4 x 4 LVDS crosspoint switch optimized for high-speed signal routing and switching over lossy FR-4 printed circuit board backplanes and balanced cables. Fully differential signal paths ensure exceptional signal integrity and noise immunity. The non-blocking architecture allows connections of any input to any output or outputs. The switch configuration can be accomplished via external pins or the System Management Bus (SMBus) interface.

The DS25CP104 features four levels (Off, Low, Medium, High) of transmit pre-emphasis (PE) and four levels (Off, Low, Medium, High) of receive equalization (EQ) settable via the SMBus interface. Off and Medium PE levels and Off and Low EQ levels are settable with the external pins. In addition, the SMBus circuitry enables the loss of signal ( ^LOS) monitors that can inform a system of the presence of an open inputs condition (e.g. disconnected cable).

Wide input common mode range allows the switch to accept signals with LVDS, CML and LVPECL levels; the output levels are LVDS. A very small package footprint requires a minimal space on the board while the flow-through pinout allows easy board layout. Each differential input and output is internally terminated with a 100 Ohm resistor to lower device insertion and return losses, reduce component count and further minimize board space.

DS25CP104