[IBIS-Users] Composite current and Initial dead time in waveform table

From: Prabhat RANJAN <prabhat.ranjan@st.com>
Date: Wed Dec 15 2010 - 19:33:35 PST

Hello Experts,

Composite current tables have been introduced in IBIS ver5.0 for better modeling of pre-driver and driver current.
In buffers, major pre-driver current flows from source just after input stimuli transition and before the output driver actually starts switching.

Also, IBIS specification recommends to remove the initial non-switching time (or dead-time or startup time) from waveform tables to avoid the over-clocking issues.

If my buffer needs to remove the initial non-switching time from waveform tables then I have to remove or shift the corresponding composite current tables also. This shifting of composite current will remove all pre-driver currents from tables and hence I shall not be able to get advantages of composite current.

In most of high speed buffers, non-switching times should be removed from waveform tables but we also need complete composite current with pre-driver current for accurate power integrity.

So, I am wondering that how composite current tables are going to be useful in above cases??

-- 
Regards
Prabhat Ranjan
STMicroelectronics
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Received on Wed Dec 15 19:34:48 2010

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