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Path: utzoo!watmath!clyde!caip!lll-crg!seismo!cmcl2!philabs!mcnc!gbn
From: gbn@mcnc.UUCP (Gary Nifong)
Newsgroups: net.lsi
Subject: SPICE Bug
Message-ID: <1561@alvin.mcnc.UUCP>
Date: Fri, 1-Aug-86 15:22:56 EDT
Article-I.D.: alvin.1561
Posted: Fri Aug  1 15:22:56 1986
Date-Received: Sun, 3-Aug-86 03:23:58 EDT
Distribution: net
Organization: Microelectronics Center of NC; RTP, NC
Lines: 21



	* SPICE USERS *

	I have discovered a serious bug in Spice2G6 that has
plagued us for several years. The problem occurs when specifying
the model parameter "level". The three levels of SPICE model
equations used to calculate current can be set with this model
parameter. If you set "level=2.0", SPICE does NOT use level "2"
model equations, the SPICE parser incorrectly reads the number 2.0
and defaults to level "1". You must change it to integer "level=2"
for the correct model selection. SPICE prints that it is using level
"2.0", but in actuality level "1" equations are generating the
current.
	This means all of those models from MOSIS and elsewhere
have been fooling us for years. Half of all SPICE models that we
have received from various sites have been set to "level=2.0". 
	This bug is likely to be found in various versions of SPICE
since it has been in the code forever.  Also, break the news lightly
to the circuit designers (ours couldn't stop swearing for several
minutes).