[PSOC 4000S] IMO best trimming performance?

[frprc_1262176]

Hi guys,

in my application I need to trim IMO with WCO. The MCU used is CY8C4024AZI-S413.

In Creator IDE (4.2), IMO accuracy steps down from +/-2% (without WCO) to +/-0.2% (with WCO).

The +/-0.2% is obtained using the default WCO accuracy value (150 PPM).

Trying to lower it to (for example) 10 PPM I expected to see the IMO accuracy becoming lower but this was not the case.

Reading PSOC 4000S TRM, I read:

1.2 System-Wide resources / 1.5.1 Clocking System

"The WCO is a 32-kHz watch crystal oscillator. It is used to dynamically trim the IMO to an accuracy of ±1 percent to enable precision timing applications."

So this differs from what Creator IDE says.

Does changing WCO accuracy effectively impact final IMO accuracy? To what extent?

What is the best IMO accuracy? The TRM seems to not report this info.

Regards,

FP

[Ekta_N]

Hello,

When we use WCO (DPLL + WCO)  to trim IMO we get an accuracy of +/-0.2 percent across all supported IMO frequencies, i.e. 24 MHz to 48MHz.

The TRM mentions that is it possible to dynamically trim IMO to +/- 1% accuracy using WCO. This is also correct within the part family.

Regards

Ekta

[frprc_1262176]

Hi Ekta,

Thanks for the response.

so, in short, is not possible to get better performance than +/-0.2 percent for IMO trimming?

Regards,

FP

[Ekta_N · Accepted solution]

Hi FP

The best possible accuracy for IMO using WCO+ DPLL IS +/-0.2% across all possible frequency ranges

Regards

Ekta

[YoIs_1298666]

Hello,

How should we consider the accuracy in the range of -40 to + 85 ° C?

For example, if we use CM8V-T1A 0.3 of Micro Crystal the Frequency vs Temperature Characteristics is below.

Can we have the accuracy for IMO in +/- 0.2%?

Best regards,

Yocchi