At 11:11 20/10/99 +1000, you wrote:
>I gather the Analog Devices MAX666 equivalent would be the ADM666(A?). Any
>particular reason you decided not to use this? I am looking at a data
>aquisition system and was considering adding battery operation. I was
>thinking of using the configuration described in the ADM666A datasheets. In
>this the voltage regulator is connected to both external power and
>rechargable (NiCad in example) battery power. Through it's low voltage
>detects, it is used to automatically trigger trickle charging of the
>rechargable batteries of the power supply when they are low on charge. Due
>to the use of NiCad's it deischarges them through a LED first to prevent
>memory.

Use the AD device, ask Andy why, as we both have been caught with the
voltage overshoot by the MAX part

Dennis





>
>I probably would have tried to use a rechargable cell without memory to
>allow trickle charging during normal mains powered operations. Were there
>any particular problems with the ADM666 that you found? Would they effect
>this application? Is there an easier\cheaper way to do this? Can anyone
>suggest a replacement for the Analog Devices voltage regulator? I live in
>Australia and have found Analog Devices parts very hard to source, which is
>a pity as they have a lot of nice looking products.
>
>Tom.
>----- Original Message -----
>From: William K. Borsum <borsum@DASCOR.COM>
>To: <PICLIST@MITVMA.MIT.EDU>
>Sent: Tuesday, October 19, 1999 12:08 PM
>Subject: low Power Comparators--summary of findings
>
>
>> Since several of you asked for my findings on low power comparators, here
>> goes:
>>
>> History:
>> Original requirement was for a low battery voltage detector circuit for a
>> PIC based data logger.  9.5 volt batteries could decay to around 6.8 volts
>> before the combined diode and regulator drops would allow the analog
>> references to loose stability.
><SNIP>
>> Original circuit used the Analog devices equivalent to the MAX666
>regulator
>>  with a comparator built in.
>> Hope this helps
>> kelly
>>
>> William K. Borsum, P.E. -- OEM Dataloggers and Instrumentation Systems
>> <borsum@dascor.com> & <www.dascor.com>San Diego, California, USA
>
>