Battery switch for RTC

[kkdelabaca]

batterypower for ds1337

Hello,

I am designing a clock with the RTC (DS1337) and have a small problem:
When the power is OFF, I need that the clock continues working.

Somebody recommends to me a commutator for the voltage of the RTC?

Regards!!

kkdelabaca

 

[IanP]

Have a look at the DS1210:
**broken link removed**
This IC unconditionally write protects when VCC is out-of-tolerance and automatically switches to battery when power-fail occurs or on power-off ..

Regards,
IanP

 

[kkdelabaca]

Hello IanP,

I think that the DS1210 is a good solution. But if you put a pair of diodes 1N4148 is most cheaper. Exist some problem using this circuit?

|o----DIODE----o VCC (5v)
|
|o----DIODE----o batery (3v)
|
|------------------------------o Power of DS1337