Does anyone know whether the discrete brownout circuit that MChip
recommend i.e the transistor and zener circuit, is significantly less
reliable than the Dallas chip, which I suppose will be much more
precise. How much do they cost?

> ----------
> From:         Tom Handley[SMTP:thandley@TELEPORT.COM]
> Reply To:     pic microcontroller discussion list
> Sent:         Thursday, January 29, 1998 12:53 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: pic lock-up
>
> re: Brown-out
>
>    Andy, I also got `bit' by the PIC brown-out circuitry. In my case,
> I'm
> using Maxim devices. The Dallas products are also a good option.
>
>    - Tom
>
> At 10:06 PM 1/26/98 -0500, you wrote:
> [snip]
> >Oh, my.  I have spent the past two weeks working with this one.  I've
> put
> >hardware together to fix the problem, basically a daughterboard for
> the PIC
> >with a reset chip on it.
> [snip]
> >To remedy the situation, we are requiring all future units to have a
> Dallas
> >DS1233-5 reset chip installed.  I investigated other chips (such as
> >Panasonic's from Digi-Key) and found it to have the best parameters.
> It
> >trips very reliably at 4.5V (+/- 5% is the spec, but reality is much
> >tighter), generates a reset pulse a minimum of 300mS wide, and stays
> low
> >until power is up about 4.5V for 300mS.
> [snip]
> >==================================================================
> >Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865
> >          Hardware & Software for Industry & R/C Hobbies
> >        "Go fast, turn right, and keep the wet side down!"
> >==================================================================
>