L9960 pcb design

[DiogoPedrosa]

 

Hey,

I'm planning on building an ETC to control a throttle valve using the L9960 H-bridge. I'm currently in the process of designing a PCB for it. The driver is supposed to have 12V as VsV_sVs​ and handle up to 10A max as output load. The PCB I'm designing can only be a maximum of 2 layers. Is it safe to use this kind of driver on a thin board like this? My thought process is to place a large ground plane around it and use a metal plate to dissipate heat.

I've read the application note AN4867 for the L9960/L9960T automotive integrated H-bridges by STMicroelectronics, but I couldn't understand much of it. There were some variables I couldn't comprehend.

Should I just change the values inside this table and calculate it? 

 

[Ignazio Testoni]

Hello Diogo,

for what concern the mentioned table, yes, you should change the relevant value.

For the power dissipation, you can use for sure a two layer PCB.

In order to improve the thermal performances we suggest to use large copper dissipation area in the bottom part through thermal vias.

For PSSO36 package the example below can be a good starting point.

This is using a 8cm^2 copper square in the bottom with 100% of the footprint covered by thermal vias.

With this kind of PCB we can reach possible value of around 36 C/W for Rthjamb.

Situation can be more improved using also copper thermal area on the top, being PSSO36 a dual in line package with exposed pad.

Please come back in case of further questions.

 

Best Regards.

Ignazio