Can I adjust the negative resistance of an external crystal oscillator?

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NXTY_Tatebayasi
Level 5
Level 5
Distributor - NEXTY (Japan)
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Hi, Community

I measured the margin for oscillation stop with the ECO trimmed, it was less than 1.
I would like to adjust the negative resistance because I want to ensure the margin of the phase margin is more than 5 times that of the ESR, but can I adjust it with the register setting of the PSoC4?

Or should it be adjusted only by the constant of the circuit connected to the ECO?

 

If negative resistance can be adjusted in the register settings of the PSoC4, please tell me the corresponding register.

 

Best Regards,

Chihiro Tatebayashi

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1 Solution

Hi @NXTY_Tatebayasi ,

No, negative resistance cannot be adjusted through register settings in the PSoC4. Negative resistance is a characteristic of certain electronic components and cannot be adjusted through typical register settings. Register settings generally control the behavior of the microcontroller itself, such as configuring the clock speed or enabling/disabling specific peripherals.

Best Regards,
Rakesh

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4 Replies
Rakesh_Patrudu
Moderator
Moderator
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25 solutions authored 5 likes given 50 replies posted

Hi @NXTY_Tatebayasi ,

Please specify which PSoC 4 device you are using, and make sure you followed the necessary crystal requirements when calculating the transconductance and Vpp. These values rely on a various factor, such as the crystal frequency, the load capacitance, and the system's operating conditions.

Best Regards,
Rakesh

 

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NXTY_Tatebayasi
Level 5
Level 5
Distributor - NEXTY (Japan)
50 questions asked 25 likes received 250 sign-ins

Hi, @Rakesh_Patrudu 

Thank you for your reply.

I am using  PSoC 4100S Max.

The frequency of the crystal oscillator I am using is 24 MHz and the load capacitance is 8 pF.
The datasheet states that the maximum ESR of the crystal oscillator is 150Ω.

Can this problem be solved by adjusting the registers in PSoC 4100S max?

 

Best Regards,

Chihiro Tatebayashi

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Hi @NXTY_Tatebayasi ,

No, negative resistance cannot be adjusted through register settings in the PSoC4. Negative resistance is a characteristic of certain electronic components and cannot be adjusted through typical register settings. Register settings generally control the behavior of the microcontroller itself, such as configuring the clock speed or enabling/disabling specific peripherals.

Best Regards,
Rakesh

NXTY_Tatebayasi
Level 5
Level 5
Distributor - NEXTY (Japan)
50 questions asked 25 likes received 250 sign-ins

Hi, @Rakesh_Patrudu 

Thank you for your reply.
I understood that the adjustment of the negative resistance depends on the characteristics of the crystal and is not adjustable on the microcontrollers.

I also understood that variables listed in the PSoC4 architecture TRM are intended to adjust for variations when mounted on the board, and not to adjust the negative resistance of the crystal oscillator.

 

Best Regards,

Chihiro Tatebayashi

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