tirsdag den 28. april 2020 kl. 19.28.28 UTC+2 skrev bitrex:
On 4/28/2020 1:24 PM, bitrex wrote:
On 4/28/2020 1:03 PM, jlarkin@highlandsniptechnology.com wrote:
On Tue, 28 Apr 2020 12:45:58 -0400, bitrex <user@example.net> wrote:
On 4/28/2020 11:03 AM, Winfield Hill wrote:
bitrex wrote...
At 30 volts into a 220 ohm load at 1 MHz she get a
lil warm to the touch.
  What about 5 or 10MHz into a modest capacitance-
  only load? Test temp with wetted fingertip,
  is OK if it doesn't sizzle, or sizzles slowly.
I'll try that (with the good ones!)
These should draw about 2-3mA quiescent. if it starts drawing 70mA from
the supply in the test circuit immediately with no signal, welp it's a
goner.
They're thermally protected but 2x overvoltage on the secondary does
seem to kill 'em reliably. Thinking about adding a Zener + small SCR
crowbar daughter-board for when I test them in future but IDK if it will
react fast enough; zapping $5 parts may be no big loss for JL but that's
an ouch for a one-man shop!
Talk a rep out of some samples!
Their sample policy for the hoi polloi is a bit stingy, 4 parts per
request per month and no more than 2 of any single part. These ship from
Singapore and take two weeks, hardly worth it.
Their corporate HQ is right down the street in Norwood MA, last time I
tried to even talk with a rep they kinda want your life story first, who
are you, who do you work for, what are you working on, how many you
gonna sell, how soon.
They seem like a typical very top-down stodgy New England tech company.
Prolly why they're still in New England.
One thing Maxim is pretty good at is the samples. Kinda like a drug
dealer I suppose.
I think drug dealers are usually able to sell you more of the product
after they get you hooked
On 4/29/2020 8:07 PM, Phil Hobbs wrote:
On 2020-04-28 00:48, bitrex wrote:
On 4/28/2020 12:42 AM, jlarkin@highlandsniptechnology.com wrote:
On Tue, 28 Apr 2020 00:08:53 -0400, bitrex <user@example.net
wrote:
https://www.dropbox.com/s/gv2ta7zik7weyxt/IMG_20200427_235520731.jpg?dl=0
Test rig for the mighty ADuM4120. 30 volts to the right power
supply line and 3.3/5 volt logic level to the left. A very nice
isolated gate driver. And at over $4 a piece in singles a real
bummer when someone who isn't me wrecks one up by accident
connecting the MOSFET source/drains wrong on the
high-side/low-side switching circuit. or a couple.
I can write that off as a business loss, right?
The bummer about most integrated gate drivers is the high prop
delay.
But is $4 really an issue?
That's the most expensive part i've ever blown!
You make transistor AM radios or something?
Mostly audio-related stuff and one-offs for pro musos, and contract work
for artists/art installations and theater is what it's been for some
time. Very little in that realm requires much in the way of boutique parts.
I'm branching out though, going faster. There's lots of ways to burn
things out pushing watts at even single-digit MHz I'm learning new ways
every day
On 2020-04-28 00:48, bitrex wrote:
On 4/28/2020 12:42 AM, jlarkin@highlandsniptechnology.com wrote:
On Tue, 28 Apr 2020 00:08:53 -0400, bitrex <user@example.net
wrote:
https://www.dropbox.com/s/gv2ta7zik7weyxt/IMG_20200427_235520731.jpg?dl=0
Test rig for the mighty ADuM4120. 30 volts to the right power
supply line and 3.3/5 volt logic level to the left. A very nice
isolated gate driver. And at over $4 a piece in singles a real
bummer when someone who isn't me wrecks one up by accident
connecting the MOSFET source/drains wrong on the
high-side/low-side switching circuit. or a couple.
I can write that off as a business loss, right?
The bummer about most integrated gate drivers is the high prop
delay.
But is $4 really an issue?
That's the most expensive part i've ever blown!
You make transistor AM radios or something?
I guess the guys in the auto repair biz have it worse, though
The most expensive thing I ever destroyed was an adjustable optical
fibre coupler, circa 1984 when I was a grad student. It used two SM
fibres embedded in blocks of epoxy, gently curved to expose the fibres
at the surface in the middle, and carefully lapped so that the cores
were nearly but not quite at the surface.
You put a drop of index oil between them, and adjusted them laterally
with differential micrometers to get the coupling you wanted. It took
several days for a skilled technician to make one.
The one I had was borrowed, and because I was so nervous I wound up
ripping out three of the fibre ends in an afternoon.
One of those character-shaping episodes.
Cheers
Phil Hobbs