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From: abali@parts.eng.ohio-state.edu (Bulent Abali)
Newsgroups: sci.electronics
Subject: Re: NMOS/TTL driving CMOS?
Message-ID: <2372@quanta.eng.ohio-state.edu>
Date: 8 Jun 89 16:47:00 GMT
References: <811@tekno.chalmers.se>
Sender: news@quanta.eng.ohio-state.edu
Reply-To: abali@parts.eng.ohio-state.edu (Bulent Abali)
Organization: Ohio State Univ, College of Engineering
Lines: 16

In article <811@tekno.chalmers.se> foperator@tekno.chalmers.se (Daniel Berglund) writes:
>Is it possible for an NMOS device (in this case, a 68000) to utilize CMOS
>(74HCxx) interface circuits? The data sheets say that Voh from the 68000 is 
>_at least_ 2.4 V (and at most Vcc), but an HC device wants at least 3.15 V to be
>happy (@Vcc=5V). 

Connect a pullup resistor between 68000 output and Vcc.
Resistor must be large enough so that I_OL current rating 
of 68000 output is not exceeded (1K-4.7K may do it).
 

-=-
Bulent Abali
Ohio State Univ., Dept.of Electrical Eng.
2015 Neil Av. Columbus, Ohio 43210
abali@baloo.eng.ohio-state.edu