Electronics Forum / Design / January 2007

I'm planning an FPGA design that will be using SDRAM (DDR Winbond
W9425G6DH5) and NAND Flash (ST NAND018W3B2AN6E). I'm not particularly
experienced in DDR memory design and there are other issues that need my
attention other then just DDR RAM design.

I need some advice regarding closing the feedback loop of a halfbridge
voltagemode smps.
I need to calculate the power circuit gain. As far as I know, this is
determined by taking transformer peak secondary voltage divided by

I want to use PWM to adjust the input of a 60 Hz high current output
transformer (instead of using a powerstat), and I would like to run a
simulation on it to see the waveform of the current applied to the load
under various conditions. The transformer I want to model consists of ...

I am looking for SD (Secure Digital) memory that can be programmed only
once.  Basically, once programmed, it cannot be erased.  I searched the web,
but I did not find any.  Please let me know if you are aware of such
technology.  Thanks.

I am trying to test a generator that has a boost feature that uses a 12V
battery to provide an extra 500 watts of power when needed for 10 seconds
maximum.  This is a Yamaha EF3000ISEB.
I question whether the boost feature works or not on the one I have.  The

This is my first post and I'm pretty new at this, so take it easy on
me. :)
Need to hook up an impact/pressure senor to Multicolor LEDs. I need to
be able display a particular color LED to it's corresponding impact/

Is there a way to write-protect microSD flash cards?  There is no mechanical
switch on the little card.  Can it be done by software?
Thanks
T.I.

What's all that about then?
DNA

I was checking a dozen of 2N3904 I got in stock in the zener mode (with 15V
and 10K limiting resistor) and they all give the same voltage, about 8.2V.
And quite a sharp knee.
Anyone can confirm if this voltage is always the same from batch to batch?

Anyone have a sense for what the leakage range for ceramic chip
capacitors (0201 - 0603 packages) is?
In particular I'm looking for a 10nf 25-50v ceramic cap in let's say
an 0402 package with about a +/-10% tolerance or better.

This thing is driving me nuts. I have a TA2009 audio amp module. I
want it to drive a PA type step-up transformer for voltage gain. IOW
around 200V out. The signal is a 60Hz sinewave. The secondary is to be
connected across a negligible load resistance, eg. wide area coil of

This should amuse Microsoft in view of it happening before Vista's official
release.
Apparently provoked by being unable to watch the HD DVD he'd bought because he
didn't have a 'compliant' monitor 'muslix64' decided to hack it.

From what I've read, and from my perspective, we engineers
should avoid Vista at all costs, while we can.  Several of
my co-workers have rushed to purchase new laptops, etc.,
now, while they still come with Windows XP.  I've purchased

Is it possible to run a buck-boost or flyback SMPS from a 0.2Vpp
signal line?  My signal has bandwith from 1-5K with low output
impedance.  I am looking to trickle charge a 3.3V battery.  I would be
happy if I could get a couple of mA at 3 to 5 volts.