Power Design Reference Documentation?

MikeH

Other Parts Discussed in Thread: OMAP-L138

Is there a reference document for the DC power supply design architecture and requirements for the OMAP-L138? I am particularly interested in how the power for the USB VDDs is routed/connected internal to the megamodule. Where can I find the definition and electrical requirements for the VDD33_USB1 and VDD33A_USB0 pins (P15, N18)?

Thx,

MIkeH

over 14 years ago

0 clam over 14 years ago

TI__Expert 8785 points

The definition and electrical requirements should be in the OMAP-L138 datasheet.

Section 5.2: describes the purpose of each power rail
Section 6.3.2: describes the required power on sequence

Also, the OMAP-L138 power management page, http://focus.ti.com/analog/docs/refdesignovw.tsp?familyId=64&contentType=2&genContentId=55935, should contain additional app notes on how to interface a PMIC to the OMAP-L138.

--Christina

0 MikeH over 14 years ago in reply to clam

Guru 15580 points

Thanks Christina. But what I am looking for is the detail voltage and current requirements for each pin of the device. My current quest is to find a document that tells me how much current a GPIO line can source/sink so that I can properly drive a LED. Can you point such a document out to me?

thx

MikeH

0 clam over 14 years ago in reply to MikeH

TI__Expert 8785 points

The Electrical Characteristics (Section 5.3) of the datasheet should specify the source/sink current of a pin (IOH and IOL).

--Christina

0 MikeH over 14 years ago in reply to clam

Guru 15580 points

Hmmm.... Thanks for pointing this out.

It appears that the GPIO ports of the OMAP-L138 cannot directly drive an LED....? (+/- 6mA). Is this correct?

MikeH

0 Soren Steen Christensen over 14 years ago in reply to MikeH

Genius 3685 points

Correct - The pins were not designed to drive LEDs directly, and your finding of +/-6mA is as well what I remember being the maximum limit...

Hope this helps you forward
Søren

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Power Design Reference Documentation?