Newsgroups: sci.electronics
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: SRAM Battery backup
Message-ID: <1989May15.043845.25572@utzoo.uucp>
Organization: U of Toronto Zoology
References: <657@serene.UUCP>
Date: Mon, 15 May 89 04:38:45 GMT

My understanding is that it's non-trivial to build circuitry that will
reliably keep a battery-backed RAM out of trouble during powerup and
powerdown.  If you want a solution quickly, buying one is probably simplest.

>I know Maxim and Dallas Semiconductor make chips that tame this problem, 
>but I'm wondering if they're actually necessary.  Does anyone have Dallas
>Semi's address?

Dallas Semi is at 4350 Beltwood Pkwy S, Dallas Texas 75244, (214)450-0400.
They make a nice gadget called a "smart socket" that is probably just what
you want -- it's a socket for a standard static RAM (actually there are
several depending on exactly what size of RAM) that includes batteries and
a switching circuit.  Use one of these instead of a standard socket and
you have battery backup.  They are not inordinately expensive.
-- 
Subversion, n:  a superset     |     Henry Spencer at U of Toronto Zoology
of a subset.    --J.J. Horning | uunet!attcan!utzoo!henry henry@zoo.toronto.edu