On Tue, Oct 08, 2002 at 06:40:43PM +0200, Matthias Weingart wrote:
> A good solution could be to connect the power supply of the MSP430 to
> the output of a special reset circuit - that circuit should have a
> high side switch and a low side switch.
> The high side switch is on if the voltage is ok. The MSP gets the power
> through the highside switch. It is off and the low side switch is on
> at power failure to bring the voltage at the MSP430 down very fast.
> I think there is no ready made chip for this and I have not yet a good
> an reliable discrete solution. It is difficult to keep it working below 1
> volt,
> pn and zener voltages are temperature dependent, zeners need current ...
> Maybe a combination of a voltage monitor chip and some external components
> could be the solution, but hey I am ending now with 90% of my components on
> the pcb used for the reset circuit ;-(.
A MXD1815 (maxim-ic.com) or similar (MAX803, MAX6381) with the push-pull
output connected to the power supply pin of the MSP430 will do the job - but
only for low currents (<150uA?).
Matthias
