Create Custom Part

Hi,

Yes, the "Create a custom part" feature is still available in WEBENCH.

Maybe the viewing window was not open fully which prevented the "Create a Custom Part" button from showing.

If you are still having trouble, please send me your design requirements so I can replicate the issue.

Regards,

LaRita Gwie

What browser and version are you using?  My gut feel is that it is a compatibility issue.

John Bateson

Hi,

I'm using IE8.

Regards,

LaRita Gwie

I reverted my IE9 back to IE8 - same problem.  I also tried the same on my Macbook with Safari and Firefox.  Same issue.  So I'm guessing that there is something associated with my account that is causing this.  If you could pass this by one of the web developers I would appreciate it.  In the meantime, I'm going to try opening a brand new account to see if that works.

Thanks.

John Bateson

Hi,

I have passed this along to one of the web developers.  By the way, which part number are you trying to design with?  Also, what are your design requirements?  We want to try to replicate the problem.

Regards,

LaRita Gwie

The problem is design specific and has nothing to do with the browser, computer, or my account.  If I select a different design, things are as they should be and create custom part appears. 

This is the broken design:

5706.webench_design_1089656_90_706924539.pdf

Let me know if there ever is a fix.

Thanks.

John Bateson

Hi,

SEPIC circuit calculators were developed using standard components only and can't process custom parts which is why the "Create a custom part" button is disabled.  This issue is in the queue to be addressed in the future. 

Sorry for the inconvenience,

LaRita Gwie

Hey John,

Based on your design input, 18-24Vin, 35Vout, 1AIout; I would suggest to use the LM5022 Boost Topology.  Is there a specific reason you have elected to use the SEPIC topology?  As noted by LaRita, that SEPIC doesn’t support custom component option.

Do you have any plans to address this issue? I am trying to design a SEPIC circuit and have run into the same issue. I am using the LM3481. I need to use a SEPIC design because my input needs to be isolated from my output in the case of a short circuit. Not being able to add custom components is an inconvenience as I won't be using the exact components recommended in the design. 

To resolve my problem, I changed to an Analog Device part (ADP1621).  Their calculator is based on an Excel spreadsheet and has ceramic caps in the component list.  Worked for me.

I appreciate the suggestion, but I need a 12Vin and none of the AD parts seem to offer that high of an input voltage. 

I'm using this part in a 24V to 35V SEPIC boost circuit.  I've also made my own spreadsheet to calculate the values for the LM part.  The problem is getting the correct parameters for the caps.

 Hi Ben,

Let me apologize in front that the current WEBENCH SEPIC designs are somewhat restrictive adding custom components into the schematic.  It’s in our plan to enable custom components for SEPIC designs in the near future. 

I think the critical design of any SEPIC is a good layout.  If you have an interest using either the LM3481 and LM5022, please let me know, I can provide the source file in Altium or other formats.

Also, please provide your design requirement and let us help you by providing a fully working solution:  Vinmin,VinMax, Iout, Vout, or maybe desire operating freq. and your personal components you want to use.

You can reach me at howard.chen@ti.com

Howard,

 Thanks for the response. 

 I am planning to go ahead with the LM3481 at this point. My main question is why the Tantalum capacitors are used in the design. I would prefer to use Ceramic capacitors and as John pointed out, the Analog Devices ADP1621 design seems to get by with 0805 sized capacitors on the input and output. 

 My requirements are 12Vin and 24Vout @350mA. 

 Here's a link to the design I have been working on: 

 http://webench.ti.com/appinfo/webench/scripts/SD2.cgi?ID=152077::power::ben.missele@digidescorp.com