On 01/07/2011 02:40, Kerry Wentworth wrote:
> David wrote:
>> On 01/07/2011 02:10, Kerry Wentworth wrote:
>>
>>> If you use the MCLR as an input, you will need to turn VCC on and off a=
t
>>> the right time to get into programming mode. (VCC off, MCLR to VPP, VCC
>>> on)  From your schematic, it does not appear that the programmer
>>> controls VCC.
>>>
>>
>> Actually it could, provided the battery was not present.  The programmer
>> is just a PK2 clone.
>>
> Will an MCP1640 allow you to apply power to Vout while Vin is
> unpowered?   Some regulators don't like that.

A good point, I should check.  The datasheet says, for absolute maximum=20
ratings:

"EN, FB, VIN, VSW, VOUT-GND ... +6.5V"

There do not appear to be any special maximums relating to the Vout pin.=20
  However, I am sure the FET has a maximum reverse voltage, will go=20
hunting further.

David

--=20
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