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From: firstname.lastname@example.org (Allan Herriman)
Subject: Re: Line-powered EIA-232 interface
Date: Wed, 18 Dec 2002 04:29:19 GMT
Organization: Agilent Technologies
References: <email@example.com> <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org>
NNTP-Posting-Date: Wed, 18 Dec 2002 04:29:21 +0000 (UTC)
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On Tue, 17 Dec 2002 18:37:03 +0100, Oliver Betz
>email@example.com (Allan Herriman) wrote:
>>>Ack. And the data sheets don't say too much about 766x startup without
>>yes, that's why I said:
>>>> Put a diode from your laptop +3V rail to the '7660 +ve rail to avoid
>>>> startup problems.
>Maybe I misunderstand completely what you intend to do.
>The OP wrote: "Want to interface it to a (laptop) PC's EIA-232
>interface." IMHO no possibility to access the "laptop +3V rail".
>Supplying the 766x from the Li battery is also no option, since "the
>battery should last several years" and 0,2mA * 40000h is 8Ah...
Ah, right. I misread the OP's requirements.
Higher voltage parts like the LTC1144 may be better than the '7660 in
this application. With the addition of some diodes (see figure 9 in
http://www.linear.com/pdf/lt1144.pdf ) it should be able to start
without needing to draw any current from the Li battery.
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