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Logic Design for Array-Based Circuits

by Donnamaie E. White

Copyright © 1996, 2001, 2002 Donnamaie E. White

 

Timing Analysis for Arrays

Last Edit July 22, 2001


k-Factors

The k-factor for an internal macro output pin is the drive factor expressed in ns/LU (Load Units) that is used to convert the total net load units into time. As detailed above, load units are attributed to electrical fan-in loading, physical metal length loading and electrical wire-OR loading. Within an array series, the k-Factors vary by macro option and by edge direction. Examples are shown in Table 5-3 for the Q5000 Series (bipolar) and the Q20000 Series (high-speed bipolar) arrays.

Table 5-3a Example K-Factors - Option Specific *

Low Power Option Macro:
k-factors rising edge 0.04 ns/LU
falling edge 0.08 ns/LU
Standard Option Macro:
k-factors rising edge 0.04 ns/LU
falling edge 0.04 ns/LU
High-Speed Option Macro:
k-factors rising edge 0.02 ns/LU
falling edge 0.04 ns/LU
15-Load Driver:
k-factors rising edge 0.02 ns/LU
falling edge 0.02 ns/LU
25-Load Driver:
k-factors rising edge 0.01 ns/LU
falling edge 0.01 ns/LU

* Q5000 Library, internal macros, typical values


Table 5-3b Example Com5max Library K-Factors For The AMCC Q20000 Series
kfo = knet; kcap**

Macro Type Description min/max units
ECL input, Bidi and
internal macros - L option
rising edge 2.3/5.1 ps/LU
falling edge 3.9/8.5 ps/LU
ECL input, Bidi and
internal macros - S option
rising edge 1.8/3.9 ps/LU
falling edge 3.0/6.5 ps/LU
ECL input, Bidi and
internal macros - H option
rising edge 1.4/3.1 ps/LU
falling edge 2.4/5.2 ps/LU
ECL input, Bidi and
internal macros - drivers
rising edge 1.1/2.3 ps/LU
falling edge 1.5/3.3 ps/LU
ECL output - 50 ohm
standard
rising edge 16.0/36.0 ps/pF
falling edge 20.0/44.0 ps/pF
ECL output - 25 ohm
Darlington
rising edge 13.0/30.0 ps/pF
falling edge 15.0/34.0 ps/pF
ECL output - 50 ohm
Darlington
rising edge 13.0/30.0 ps/pF
falling edge 21.0/46.0 ps/pF
TTL input and Bidi (Non-
-Turbo) S, L, H options
rising edge 3.0/6.5 ps/LU
falling edge 6.0/13.0 ps/LU
TTL input and Bidi (Turbo)
S, L, H options
rising edge 1.4/3.1 ps/LU
falling edge 2.4/5.2 ps/LU
TTL output - 20 mA rising edge 33.0/72.0 ps/pF
falling edge 33.0/72.0 ps/pF
TTL output - 8 mA rising edge 33.0/72.0 ps/pF
falling edge 54.0/117.0 ps/pF

** Individual macro k-factors are specified in the macro library documentation in the AMCC Q20000 Design Manual, Volume I, Section 6. Units are min/max spread for the Commercial 5V library only.

Copyright @ 2001, 2002 Donnamaie E. White, White Enterprises
For problems or questions on these pages, contact dew@Donnamaie.com




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