MSP430FR5739: looking for crystal recommendations

Hi,

what kind of crystal are you looking for 32kHz or high frequency?

Best regards

Peter

Hi,

there is an application report on 32kHz oscillators and MSP430. The document is rather focusing on how to design and test a crystal oscillator setup, but derived from that, you can find selection criteria for a crystal. www.ti.com/.../slaa322d.pdf

As mentioned this application report is focusing on 32kHz crystals, but the criteria basically apply also for high frequency AT cut crystals.

From top level point of view, what are the interesting parameters of a crystal?

1. ESR - reflecting losses of the crystal the oscillator/driver in the MSP needs to compensate. Lower ESR is better. ESR decreases with crystal frequency so when comparing you need to compare crystal with same frequency.

2. Capacitive load. Lower capacitive load, less power (also combined with ESR).

3. Higher power consumption, as long as the oscillator is able to provide it, is on the other hand equivalent to higher robustness versus disturbance.

4. Lower ESR means faster startup time, better safety margin (see application report)

5. Shunt capacitance. Lower shunt capacitance is better than higher, but the relation to load capacitance needs to be considered too. Shunt capacitance very close to load capacitance values can mean weaker stability.

Best regards

Peter

Hi Peter,  There is a need for better timing accuracy than the DCO can provide, hence the need for a crystal recommendation if you have one?

Hi Ajayt,

understood. Unfortunately you have not provided any information on the use case nor required parameters and performance of the oscillator setup. Also the question about the robustness of the oscillator setup and the application itself has not been addressed. What about the current consumption?

It is like asking "Can you recommend a microcontroller?" without giving any additional information....

Best regards

Peter

Hi Peter, the application is driving the oscillator circuit of the msp430 with more accuracy than the DCO can achieve is all I am allowed to know.  The data sheet shows DCO accuracy asDoc3.docx

OK