Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!ucsd!ames!vsi1!wyse!mips!earl@wright
From: earl@wright (Earl Killian)
Newsgroups: comp.arch
Subject: Re: ETA-10: CMOS or ECL?
Message-ID: <6984@wright.mips.COM>
Date: 26 Oct 88 00:21:31 GMT
References: <3539@phri.UUCP> <126@ecicrl.UUCP> <23368@amdcad.AMD.COM>
Sender: earl@mips.COM
Reply-To: earl@wright (Earl Killian)
Organization: MIPS Computer Systems, Sunnyvale CA
Lines: 23
In-reply-to: phil@diablo.amd.com (Phil Ngai)

In article <23368@amdcad.AMD.COM>, phil@diablo (Phil Ngai) writes:
>Not by a long shot. 74HC is comparable to 74LS. 74AC competes nicely
>with 74AS and 74F, however, particularly for driving RAM arrays.
>Fairchild had a really nice CMOS line. Unfortunately, National lost
>the data book when they bought Fairchild. (ever try to get a 74AC
>data book from National?) I just hope they didn't lose anything
>*important*.

Don't worry about Fairchild.  FACT is now slow CMOS.

Comparing the same part (374), clock to output (max), in different families:
	TI ALS (TTL) 74ALS374			16.0ns (50pf)
	Fairchild FACT (CMOS) 74AC374 		11.0ns (50pf)
	Fairchild FAST (TTL) 74F374		10.0ns (50pf)
	TI AS (TTL) 74AS374			 9.0ns (50pf)
	IDT FCT (CMOS) 74FCT374A		 7.2ns (50pf)
For comparison, equivalent ECL parts would be
	Fairchild 100K (ECL) 100141		 2.3ns (50ohm)
	Sony CXB1109Q				 0.8ns (50ohm)

Conclusion: In 1988, ECL < CMOS < TTL, at least for MSI.  It's still
the case that VLSI ECL < VLSI CMOS, but that gap is closing.
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