MSP430F5659: XT1CLK vs REFOCLK

Boaz Aizenshtark said:

Part Number: MSP430F5659

Hello,

how does the internal REFOCLK compare with a typical external 50 ppm crystal oscillator, in terms of: (i) accuracy, (ii) current consumption, (iii) robustness?

In general, MSP430 internal clock sources are lower power and accuracy related to external XT1 / XT2. If accuracy is issue for you, use XT2 directly or divided.

Thank you, Zrno. Do you know its accuracy in ppm?

For XT1/2, accuracy is the one of the crystal.
Regards,
Peppe

Also consider following points:
Worse accuracy: typical 1.5-3% for REFO (from p.62 of datasheet), 0.005% (=50ppm, your choice) for XT1;
Worse current consumption: typical 3uA for REFO (from p.62 of datasheet), typical <1uA for a typical 32768 crystal oscillator;
Better robustness: being internal (not crystal based), REFO doesn't suffer from coupling with external crystal/caps traces (which can lead even to XT1 stops in poor designs).

Regards,

Peppe