***************************************************************************** ***************************************************************************** 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: Rejected August 26, 1994 ****************************************************************************** ****************************************************************************** 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. ****************************************************************************** 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. | ****************************************************************************** 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. ****************************************************************************** ANY OTHER BACKGROUND INFORMATION ******************************************************************************