topic Re: MCXA153VLF external crystal oscillator configuration. in MCX Microcontrollers

MCXA153VLF external crystal oscillator configuration.

bogdanurbanczyk — Mon, 28 Jul 2025 15:34:13 GMT

Hello,
MCXC44X Sub-Family Reference Manual (page 461) describes external crystal (or resonator) connections. Are 3 type of configuratons (Connection 1 to Connection 3).
Why MCXA153 Reference Manual hasn't any informations of external crystal and capacitors configuratons?
In FRDM-MCXA153 schematic is connection with 18pF capacitors and 8MHz crystal.
best regards
Bogdan

Re: MCXA153VLF external crystal oscillator configuration.

Habib_MS — Tue, 29 Jul 2025 20:45:19 GMT

Hello @bogdanurbanczyk,
You can find the oscillator frequency specifications for the crystal in Section 3.3.2.2 of the datasheet. Additionally, the section you mentioned includes a table that outlines the supported crystal frequency ranges and the different connection options available, depending on your application:

On the other hand, the load capacitor values should follow the crystal or resonator manufacturer's recommendations, as referenced in Table 20: "Oscillator DC Electrical Specifications" of the datasheet. Please keep the following recommendations in mind:

If the load capacitors (Cx, Cy) are greater than 30 pF, use Connection 3.
When using the low-frequency oscillator (RANGE = 00), the integrated capacitors can provide Cx and Cy.

BR
Habib

Re: MCXA153VLF external crystal oscillator configuration.

bogdanurbanczyk — Wed, 30 Jul 2025 06:02:29 GMT

Hello Habib,
Your answer was about the MCX C44X processor.
I need information on how to connect an external crystal (or resonator) to the MCXA153 microcontroller.
The MCXAP64M96FS3RM.pdf and MCXAP64M96FS3.pdf files do not contain any information about connecting an external crystal or capacitors.

best regards
Bogdan

Re: MCXA153VLF external crystal oscillator configuration.

Habib_MS — Wed, 30 Jul 2025 18:51:10 GMT

Hello @bogdanurbanczyk,

Apologies for the confusion.
For detailed information regarding the external crystal and load capacitors, please refer to Section 4.2, "Clock Modules" in the datasheet. This section outlines the crystal specifications as well as the recommended capacitance values based on the crystal frequency.

BR
Habib

Re: MCXA153VLF external crystal oscillator configuration.

bogdanurbanczyk — Fri, 01 Aug 2025 06:32:44 GMT

Hello Habib,
I understand that NXP recommends using FIRC with trim capability. I accept this. I will try connecting an external crystal according to the FRDM-MCXA153 schematic.
best regards
Bogdan