Bird 17, 101 points in tables

Hello IBIS members:

This BIRD extends the number of points from 100 to 101 per last IBIS Forum
discussion. Upon further reflection, the proposed number of points for the
[Pullup] and [Pulldown] tables is increased to 151 since they are mandated
to extend of larger voltage ranges. The primary reason for these extensions
is to allow automated IBIS file creation programs to sweep over the entire
voltage data range of -5V to 10V at .1V increments, capture the endpoints
and the 0V and 5V points.

Scott Bloom, Interconnectix, Inc.

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                 Buffer Issue Resolution Document (BIRD)

BIRD ID#: 17
ISSUE TITLE: Number of Points
REQUESTOR: Scott Bloom, Interconnectix, Inc.
DATE SUBMITTED: 17 July 1994
DATE REVISED:
DATE ACCEPTED BY IBIS OPEN FORUM: Pending

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STATEMENT OF THE ISSUE:

The limits on the number of points for the [Pullup] and [Pulldown] keywords
is increased from 100 to 151 to allow automated and simulated capture routines
to sweep from -5V to +10V at .1V increments. Similarly the number of points
for [GND clamp] and [POWER clamp] tables is increased from 100 to 101, again
allowing .1V increments for the [GND clamp] table from -5V to 5V. Also the
the number of points for [Rising Waveform] and [Falling Waveform] tables
is increased from 100 to 101 to allow, for example, time sweeps from 0 to 10ns
at .1ns increments.

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STATEMENT OF THE RESOLVED SPECIFICATIONS:

For the keywords [Pulldown], [Pullup], [GND Clamp], and [POWER Clamp], under
Usage Rules, the last sentence of the second paragraph is changed into two
sentences. The second paragraph becomes:

| All four columns are required under these keywords. However,
| data is only required in the typical column. If minimum
| and/or maximum current values are not available, the reserved
| word "NA" must be used. "NA" can be used for currents in the
| typical column, but numeric values MUST be specified for the
| first and last voltage points on any V/I curve. Each [Pullup]
| and [Pulldown] V/I curve must have at least 2, but not more
| than 151, voltage points. Each [GND Clamp] and [POWER Clamp]
| V/I curve must have at least 2, but not more than 101, voltage
| points.

For the keywords [Rising Waveform] and [Falling Waveform], the second to last
sentence of the first paragraph of Usage Rules is changed: It now becomes:

| Usage Rules: Each [Rising Waveform] and [Falling Waveform] keyword
| introduces a table of time vs. voltage points that
| describe the shape of an output waveform. These
| time/voltage points are taken under the conditions
| specified in the R/L/C/V_fixture and R/L/C_dut
| sub-parameters. The table itself consists of
| one column of time points, then three columns of
| voltage points in the standard typ, min, and max format.
| The four entries must be placed on a single line and
| must be separated by at least one white space or tab
| character. All four columns are required. However, data
| is only required in the typical column. If minimum
| or maximum data is not available, use the reserved word
| "NA". The first value in the time column need not be '0'.
| Time values must increase as one parses down the table.
| The waveform table can contain a maximum of 101 data
| points. A maximum of 100 waveform tables are allowed per
| model. Note that for backwards compatibility, the existing
| [Ramp] keyword is still required.
|

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ANALYSIS PATH/DATA THAT LED TO SPECIFICATION

Automated generation of IBIS file VI and time tables typically can be done
with linear voltage and linear time sweeps over the entire required range.
A typical range for CMOS and TTL devices with Vcc = 5V is from -5V to 10V
at .1V increments. This would require 151 points for the [Pullup] and
[Pulldown] tables. Similarly, the [GND Clamp] tables would be tabulated
from -5V to 5V at .1V increments, requiring 101 points. The [Rising
Waveform] and [Falling Waveform] could be presented with some utilities at
constant time increments. In order to capture a typical range such as
0 to 10ns at .1ns increments, 101 points would be needed.

Even though there may be unnecessary points, this proposal increases the
limits in a proportional manner. It allows typical ranges that align the V/I
tables to be presented without requiring any further processing.

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ANY OTHER BACKGROUND INFORMATION

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Received on Wed Jul 20 13:57:57 1994