Comments on: USB Isolator Most Frequently Asked Question

By: oleg

oleg — Thu, 09 Feb 2012 17:30:44 +0000

PSU is not included, you may use any wall wart with standard center positive round connector and 9-24V output. If you don’t have any lying around, this one will work -> http://www.sparkfun.com/products/9442 .

By: Bent

Bent — Thu, 09 Feb 2012 17:21:06 +0000

1) Does this thing come with a PSU?
2) If no PSU is supplied, then what is recommended?

By: Alex

Alex — Mon, 19 Sep 2011 17:15:36 +0000

Excuse me, LT3439

By: oleg

oleg — Mon, 19 Sep 2011 17:14:39 +0000

Won’t work – it requires 7V Vin.

By: Alex

Alex — Mon, 19 Sep 2011 17:11:59 +0000

LTM8022 1A Isolated DCDC

By: oleg

oleg — Sat, 17 Sep 2011 02:36:21 +0000

You are talking about current consumption. There is no specification which forbids USB Host port from sourcing more than 500ma. In fact, PC ports are often capable of 700+ ma and many hubs work in ganged current limiting mode, being able to source 2A from 4 ports – if you only use one port, you can have all of it.

By: Alex

Alex — Fri, 16 Sep 2011 17:16:53 +0000

Sorry, but the specification defines the usb power consumption for USB 2 is 500 mA. Efficiency of modern DC-DC 72-90%. Total output at 400 mA should be ?

By: oleg

oleg — Fri, 16 Sep 2011 17:16:23 +0000

Still working on it.

By: Alex

Alex — Fri, 16 Sep 2011 17:12:46 +0000

At May 19, 2011 at 3:39 pm you wrote:

I’m currently prototyping low noise linear regulator for new “modular” USB isolator. The new isolator will be available with switching, linear, or USB-powered isolated supply. No ETA yet.

How do you do with this project?

By: oleg

oleg — Fri, 16 Sep 2011 17:11:53 +0000

I’m planning to have this as an option in the next version of the isolator. The issue is max.current – currently, all isolated DC-DC modules are rated at 100ma max. and I wanted to be able to provide more than that.