UCC21530-Q1: The creepage at the IC level and the board level

Pin Tsai (TW FAE)

Part Number: UCC21530-Q1

Hi,

My customer is using UCC21530-Q1 and have question on the creepage design.

They are using PCB board with CTI = 175 and want to have creepage >8mm at PCB. And I have questions below:

1. In our datasheet, it mentioned External creepage is >8mm, I assume it is for IC itself, right?

2. If customer follow our design suggestion as below, it said the creepage is 8.1mm. How could we get the number 8.1 mm stated as below.

3. How to cutout at PCB will affect the creepage numerically? Like, if the cutout is 1x10 mm. Is the creepage increased by 1 mm?

Appreciate you support in this, thank you :)

over 3 years ago

0 Don Dapkus over 3 years ago

TI__Guru**** 189399 points

Hi, Pin,

We have been suffering from power outages here in Dallas which is delaying some of our team members' responses.

We will reply to your questions early next week.

0 Krystian Plaskota over 3 years ago

TI__Expert 4065 points

Hi Pin,

The external creepage is for the IC itself. The 8.1mm comes from (9.75-1.65)mm. Creepage will increase based on the shortest possible path across the PCB. This is usually straight lines that go around the cutout.