SCI-LVDS 500-MHZ DIFFERENTIAL PAD DRIVERS IN A STANDARD CMOS PROCESS

In this paper a set of high-speed differential pad cells are presented . The pad cells are designed to work with the IEEE Draft Standard for Low-Voltage Differential Signals for Scalable Coherent Interface (SCI- LVDS) [4], The standard sets specifications for high-speed point to po int communication between complex subcircuits in digital systems. The pad cells are in compliance with the draft, but are designed to operat e up to at least 500 MHz instead of the 250 MHz proposed in the draft. The pad cells presented in this paper are designed in a standard 1 mu m CMOS process using standard DIL packaging, This has proved possible despite the electrical specifications being narrowed as a result of t he doubling of the operating frequency, The circuit has ESD protection and utilizes internal termination with a single external impedance re ference and thereby facilitates ease of use and higher package density .