Can I drive differential SSTL_18 with (rebiased) LVDS

Hi all,

I need to drive 3 differential SSTL_18 receivers on a chip with a

100Mhz signal. The only SSTL_18 drivers I could find are complex 1:10 tiny uBGA devices designed for DIMMs.

Could I use an LVDS driver with the signal rebiased around Vref for this purpose? Is it necessary to cross AC levels in the SSTL spec?

The SSTL_18 AC levels specify a swing of 500mV about Vref while the DC levels require only a swing of 250mV.It would seem you have to cross the AC level to get the receiver to switch state. The DC level therafter is provided just for hysteresis. From the spec:

"The ac values indicate the voltage levels at which the receiver must meet its timing specifications. The dc values indicate the voltage levels at which the final logic state of the receiver is unambiguously defined. Once the receiver input has crossed the ac value for a sufficient period, the receiver will change to the new logic state. The new logic state will then be maintained as long as the input stays beyond the dc threshold."

I guess LVDS will not cut it but I could do it with LVPECL swings.

Any thoughts on this will be really helpful,

Thanks, Jai Aarohi Comm. jswarrier at aarohi.net

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Jai
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