MSP430F6736: MSP430F6736: settling- or on-time for external reference for SD24

Bjoern

Part Number: MSP430F6736

Hello,

in the datasheet is a value stated for the settlingtime for the internal reference, if switched on. There is also a value stated for tON for the interal reference using in conjunction with the SD24. (I assume, the only difference is, that this are 2 different references. Settling and ON are meaning the same thing?!)

So, which time I'll have to wait, if I use an external reference? OK, it will also depend on the external circuit, but will there be times I'll have to consider, which will be "produces" inside the MSP?

BTW: tSETTLE is mentioned in the footer as tREFON. Typo?

Thanks in advance!

Regards,

Björn

over 8 years ago

0 Ryan Brown1 over 8 years ago

TI__Guru**** 219597 points

Hello Björn,

Wait 75 us after the external reference has been applied to the VeREF+ pin. tSETTLE is not equivalent to tREFON, the time it takes to set the REFON bit.

Regards,
Ryan

0 Bjoern over 8 years ago in reply to Ryan Brown1

Prodigy 230 points

Thank you Ryan!

But I can't find something else concerning tREFON. How it is defined or how long is it?

Regards,
Björn

0 Ryan Brown1 over 8 years ago in reply to Bjoern

TI__Guru**** 219597 points

Björn,

It is the same as the instruction time to set the REFON bit inside of the REFCTL0, typically 4 or 5 clock cycles.

Regards,
Ryan

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MSP430F6736: MSP430F6736: settling- or on-time for external reference for SD24