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# LM5166: Output voltage accuracy

Part Number: LM5166

Hi all

Would you mind if we ask LM5166?

<Question1>
In case of LM5166Y(3.3V fixed), the datasheet shows REGULATION COMPARATOR is Min=3.23V and Max=3.37V.
Does it mean that output voltage accuracy is Min=3.23V and Max=3.37V?
So, does it contain COT and PFM mode?

<Question2>
And then, output voltage is 3.1V, Iout=75mA.
According to changing input voltage, output voltage changes.
-Input 12V :  3.190V
-Input 8V :  3.170V
-Input 14V : 3.220V
Our customer doesn't have wave form, however Ton depends on Vin, so Vout changes.
Is our recognition correct?

Kind regards,

Hirotaka Matsumoto

• Hi Hirotaka-san,

The regulation comparator Min/Max data are taken at 12Vin with internal set point 3.3V and reflect the "accuracy" of the IC internal comparator.
If you ask for the application DC/DC output voltage regulation / accuracy we can look at the line and load regulation plots in the application section of the datasheet or in the EVM user guide www.ti.com/.../snvu544.pdf.

In the LM5166 datasheet you will find in the application section 8.1 two designs.
The plots for your customer 3.3V output voltage design you will find under 8.2.2.2.8 Application Curves in Figure 65. Converter Regulation.
The plots for 5V output voltage design you will find under 8.2.1.2.9 Application Curves in Figure 54. Converter Regulation.

Best Regards,
Robert Loke
• In reply to Robert Loke:

Robert san

The datasheet P5 shows FB LINE-REG=0.005%/V.
Is this condtion PFM or COT mode?

Kind regards,

Hirotaka Matsumoto

• In reply to Hirotaka Matsumoto:

Hi Hirotaka-san,

This is a typ spec and a measure of lower FB threshold accuracy over the input voltage operating range. My understanding is that it applies to both COT and PFM modes.

Regards,
Tim