UCC2895: about frequency, test condition and graph

Yuta Nishie

Part Number: UCC2895

Hi,

Thank you for your support in the following thread.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1296011/ucc2895-frequency?tisearch=e2e-sitesearch&keymatch=%2520user%253A460063#

I have additional questions. I would appreciate your support.

1)You answered "The frequency variation is based on variation in temperature and indicate the 25 degree C could vary +/- 2% more with variation in temperature.

The frequency varies due to variation in process and production various. This variation is due to comparator thresholds, references, delays etc...", but are you correct in recognizing that these factors are related to both "frecuency" and "frequency total variation" of fosc? If there are other factors related to the above two variations, please let me know.

2)What specific condition does "Over line, temperature" described in TEST CONDITIONS of frequency total variation indicate?

3)Is there a graph showing the change in frequency due to the change in ambient temperature?

4)Does the temperature characteristic of EAOUT described on page 10 of the data sheet affect the oscillation frequency?

Best Regards,

Nishie

over 1 year ago

0 Mike O' over 1 year ago

TI__Guru* 83356 points

Hello,

Your inquiry is under review and I will get back to you shortly.

Regards,

0 Mike O' over 1 year ago in reply to Mike O'

TI__Guru* 83356 points

Hello,

I am going to forwarded your inquiry to product engineering for support.

Regards,

0 Yuta Nishie over 1 year ago in reply to Mike O'

Genius 4370 points

Hi Mike-san,

Thank you for your support.

I'm looking forward to hearing the results.

Best Regards,

Nishie

+1 Austin Cawley over 1 year ago

TI__Prodigy 60 points

Hi Nishie-san,

The ‘Frequency total variation’ spec is describing the frequency shift the device might show with a shift in ambient temperature.

There is no specific testing condition for this test other than the ambient temperature, as it is specified by design. This is indicated in the Automotive/Q1 version of the datasheet shown below.

Unfortunately, we do not have a graph we can publish for the relationship between frequency and the change in ambient temperature.

Similar to 'EAOUT to Ramp Offset', on average the f_OSC decreases as temp increases, but the two are not directly related.

Best Regards,

Austin

0 Yuta Nishie over 1 year ago in reply to Austin Cawley

Genius 4370 points

Hi Austin-san,

Thank you for your support.

Let me reconfirm the “Over line” in the test condition.

Am I correct in understanding that the Over line is when the Supply Voltage is between 10V and 16.5V?

Best Regards,

Nishie

+1 Austin Cawley over 1 year ago in reply to Yuta Nishie

TI__Prodigy 60 points

Hi Nishie-san,

Yes, that is correct.

Best Regards,

Austin

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UCC2895: about frequency, test condition and graph