A gate driver circuit

[bitrex]

<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?

 

[bitrex]

On 4/28/2020 12:08 AM, bitrex 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?

At 30 volts into a 220 ohm load at 1 MHz she get a lil warm to the
touch. Don't run it up much higher than that with that load or you're
going to burn your fingertip and I'm fresh out of ice cream sammies.

 

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?



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[bitrex]

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!

I guess the guys in the auto repair biz have it worse, though

 

[bitrex]

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?

The total prop delay on this is 79 ns, falling edge. That seems better
than most.

Oh hey, it looks like you can get 'em for $2.16 in quantities of 100
direct from Analog. Mouser's discount is only $3.47. way to undercut
your distributors

 

[Winfield Hill]

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.


--
Thanks,
- Win

 

On 28 Apr 2020 08:03:13 -0700, Winfield Hill <winfieldhill@yahoo.com>
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 can touch a 50C surface for many seconds, 60C for about 1 second,
and can interpolate reasonably well. That's easier than setting up a
thermocouple or the FLIR.

For a serious gate driver, like slamming a Cree SiC at 5 MHz, you've
got to roll your own. DEI/IXYS used to makes some real beasts, but I
think they are gone now.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[bitrex]

On 4/28/2020 12:00 PM, jlarkin@highlandsniptechnology.com wrote:

On Tue, 28 Apr 2020 00:48:33 -0400, bitrex <user@example.net> 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!

I guess the guys in the auto repair biz have it worse, though

We recently fried a couple of $200 distributed amplifier chips. I've
done better at the system level.

I learned at some point to bill the client for a few spares of all the
pricey-bits due to "development mishaps" on a prototype upfront they
seem more amenable to that at the beginning of a project than if you
tell them late in the game "Yeah so I blew up the output stage please
add $X to you bill"

 

On Tue, 28 Apr 2020 00:48:33 -0400, bitrex <user@example.net> 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!

I guess the guys in the auto repair biz have it worse, though

We recently fried a couple of $200 distributed amplifier chips. I've
done better at the system level.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[bitrex]

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.

 

[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.

 

On Tue, 28 Apr 2020 12:43:42 -0400, bitrex <user@example.net> wrote:

On 4/28/2020 12:00 PM, jlarkin@highlandsniptechnology.com wrote:
On Tue, 28 Apr 2020 00:48:33 -0400, bitrex <user@example.net> 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!

I guess the guys in the auto repair biz have it worse, though

We recently fried a couple of $200 distributed amplifier chips. I've
done better at the system level.



I learned at some point to bill the client for a few spares of all the
pricey-bits due to "development mishaps" on a prototype upfront they
seem more amenable to that at the beginning of a project than if you
tell them late in the game "Yeah so I blew up the output stage please
add $X to you bill"

The more elegant term on the invoice is "consumables."



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

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!



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Lasse Langwadt Christense]

tirsdag den 28. april 2020 kl. 18.05.58 UTC+2 skrev jla...@highlandsniptechnology.com:

On 28 Apr 2020 08:03:13 -0700, Winfield Hill <winfieldhill@yahoo.com
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 can touch a 50C surface for many seconds, 60C for about 1 second,
and can interpolate reasonably well. That's easier than setting up a
thermocouple or the FLIR.

I seem remember that back in the day 50C was the safety limit for user touchable parts like exposed heatsinks and such

 

[bitrex]

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!

 

On Tue, 28 Apr 2020 10:49:45 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

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

They'll never EOL heroin.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

On Tue, 28 Apr 2020 13:24:33 -0400, bitrex <user@example.net> 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.

Creative fiction can help.

They seem like a typical very top-down stodgy New England tech company.
Prolly why they're still in New England.

--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Lasse Langwadt Christense]

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

 

[bitrex]

On 4/28/2020 2:00 PM, jlarkin@highlandsniptechnology.com wrote:

On Tue, 28 Apr 2020 13:24:33 -0400, bitrex <user@example.net> 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.

Creative fiction can help.

"You don't _have_ to give me more samples. If you, y'know. Hate America"

 

[bitrex]

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.

at 30 volts on Vdd2 into a 100 pf load looks like it drops into thermal
protect at about 5MHz, 50% duty cycle. Output looks fine up until around
that point, though.