LM5026: Recommended handling method of unused SYNC pin

Hidekazu Someno

Expert 5130 points

Part Number: LM5026

Hi Team,

I have some questions from my customer. Please support the following inquiries.

1. What is the recommended best handling method(connection) when SYNC pin is not used?

2. Is there any design calculator tool or application note to determine external components in application circuit?

Best regards,

H. Someno

over 5 years ago

0 Teng Feng over 5 years ago

TI__Genius 13660 points

Hi H.Someno,

You can just leave the SYNC pin floating if it is not used.

Unfortunately, there is no LM5026 calculator available for LM5026. You can refer to datasheet section 8.2.2 for detailed design procedure with its corresponding application circuit as shown in figure 31.

Here are several reference designs are located here for your reference:

http://www.ti.com/tool/PMP7892

http://www.ti.com/tool/PMP11478

http://www.ti.com/tool/PMP7895

Regards

Teng

0 Hidekazu Someno over 5 years ago in reply to Teng Feng

TI__Expert 5130 points

Hi Teng,

Thanks for your reply.

According to Figure.31(Application circuit) in datasheet, C32(33pF) has been connected to SYNC pin.

Even if the SYNC terminal is not used, is it better to add this small capacitance to suppress noise sensitivity?

Regards,

H.Someno

0 Teng Feng over 5 years ago in reply to Hidekazu Someno

TI__Genius 13660 points

Hi H.Someno,

You can leave the SYNC pin floating. Do minimise the size of any copper PCB traces at this pin so that it does not pick up unwanted electrical noise.

Besides, I would also suggest adding a 33pF capacitor to reduce the noise sensitivity of this pin if there is a noise.

Regards,

Teng

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LM5026: Recommended handling method of unused SYNC pin