Oscillator Selection for STM32G4

[Chubs]

Hello Community,

I am slightly confused while selecting the external high-precision Clock source for our application that uses STM32G474RxT3 series MCUs. I want to use DSC1001DL2-024.0000T as I have these in our inventory, I checked for the operating voltage range & recommended Frequency range as given in the datasheet of STM32G474.

I however am unsure as the AN2867 specifies Crystal/Resonator list only. Can someone confirm if choosing MEMS Oscillator like DSC1001DL2-024.0000T shall be suitable or not?

Thanks in advance.

[AScha.3]

shure, no problem.

just set "bypass" clock for HSE , so cpu expect an oscillator. 

and i put an damping resistor, 50...80 ohms , in clock line, to reduce reflections. (some oscillators have so short rise time, they provoke ringing on the edges.)

[STOne-32 · Accepted solution]

Dear @Chubs 

Here is attached the VOH/VOL of the Oscillators and as well the VIH and VIL of the STM32G4 in bypass mode - They are compatible with selected frequency of 24MHz in all ranges .

 

Hope it helps you .

Cheers, 

[Chubs]

Thanks @STOne-32 for your prompt response, the AN2867 also mentions in the conclusion section of the Application Note that MEMS Oscillators are supported.

[sreejithrnair]

Hi,

As per ST application note AN2867, for the selection of 24MHz ST is recommending NDK crystal for 24 MHz as shown in the screenshot. But unfortunately, the NDK crystal parts have unconfirmed status. I have contacted the NDK manufacturer and still they are not responding. Could you suggest any alternate 24MHz part for the MCU STM32G431Mx? Or could you please confirm if I can go ahead with NDK part.

Thanks

[Chubs]

Hello @sreejithrnair,

Attaching NDK products from Digikey's listing for your reference here.

Also, you can opt for Oscillators or Crystals either of them.

I have used TI's BAW Resonators for my use case as our devices are exposed to lifetime of high vibrations.

[sreejithrnair]

Hi @Chubs 

Thanks for the information.

In my project, I am using 24MHz crystal oscillator. In the given list of Digikey NDK crystal products, the close frequency matching crystal is NDK's NSC5083D-24.576M NSC5083D-24.576M NDK America, Inc. | Crystals, Oscillators, Resonators | DigiKey which is having frequency of 24.576 MHz. Is this value permitted instead of 24 MHz frequency?

I also have found out a suitable crystal from Sunstu with exact matching specs of NDK 24MHz crystal. SXT3248EA48-24.000M Suntsu Electronics, Inc | Crystals, Oscillators, Resonators | DigiKey Marketplace

Can you please suggest if the part SXT3248EA48-24.000M is suitable contender for my application?

Regards,
Sreejith

[Chubs]

Hello @sreejithrnair,

The only thing you might have to check is if the odd frequency is able to configure PLL pre-scalers to reach USB 48Mhz clock requirements - that too if you anticipate using the USB FS peripheral. Else STM32 like many other MCUs can be clocked with frequencies over a wide range - in this case upto 48MHz.

I would recommend you to use ChatGPT to clear your fundamentals initially, that will be far more faster as well as it will help you get more structured answers to your fundamental queries, you can use this thread to confirm your choices, me & others here might help you better that way.