HF amplifier purchase

[George Herold]

On Wednesday, March 4, 2020 at 1:16:16 PM UTC-5, LM wrote:

On Wed, 04 Mar 2020 07:09:43 -0800, jlarkin@highlandsniptechnology.com
wrote:

On Tue, 3 Mar 2020 22:47:27 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

On Wednesday, March 4, 2020 at 12:57:56 AM UTC+1, John Larkin wrote:
On Tue, 3 Mar 2020 15:42:00 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50 ohms output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus

How much current do you need? Can you drive both ends opposite phases?

Some of the THS-series opamps might do it. Maybe use an eval board.


I would like to have an instrument, so I do not need to spend time on setup etc.

But, I had the same trail of thought, so I ordered this one as a backup solution:

https://dk.farnell.com/texas-instruments/ths4031evm/evaluation-module-amplifier/dp/3125639?CMP=i-bf9f-00001000

Cheers

Klaus

THS6022 is a beast.
Digikey has problems. It finds something else with that name.

You sometimes have to scroll down through a list of parts with
'same' number.
http://www.ti.com/lit/ds/symlink/ths6022.pdf

GH

 

[Joerg]

On 2020-03-03 22:58, Klaus Kragelund wrote:

On Wednesday, March 4, 2020 at 2:08:26 AM UTC+1, amdx wrote:
On 3/3/2020 5:42 PM, Klaus Kragelund wrote:
Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50 ohms
output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus


Have you looked at ENI amplifiers, I think most of them are class
A. Probably expensive, here's one, 100watts, 10kHz to 12MHz. 50 ohm
output. "The 2100L will work into any load impedance. Into a short
circuit or infinite load at some phase angles it may protect itself
at power greater than 80% rated power output. Any power reflected
due to output load mismatch is absorbed in the amplifier.
Therefore, although the output impedance is 50 ohms (maximum VSWR:
2:1), the amplifier will work into any load impedance." "Continuous
operation into any load or source impedance"

https://www.theemcshop.com/dc-220-mhz-rf-amplifiers/1336-used-ei-eni-2100l-rf-power-amplifier-10-khz-12-mhz-100-watts.html



Mikek

That is a nice selection of power HF amps

I would like something with 0 ohms output, but if I am sure I will
not short it, I could just open it and short the 50 ohms resistor

I doubt there is a 50ohms resistor in the output. It's ususally a
hard-driving direct push-pull stage and a measurement bridge. This
bridge causes power to be curbed if you are trying to do things such as
driving into a short at high power.

The manual is a bit hokey, they refer to transistors without providing
the schematic.

https://www.theemcshop.com/index.php?controller=attachment&id_attachment=333

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Wed, 4 Mar 2020 10:01:32 -0800 (PST), George Herold
<ggherold@gmail.com> wrote:

On Wednesday, March 4, 2020 at 11:31:06 AM UTC-5, jla...@highlandsniptechnology.com wrote:
On Wed, 4 Mar 2020 08:19:58 -0800 (PST), George Herold
ggherold@gmail.com> wrote:

On Wednesday, March 4, 2020 at 10:09:52 AM UTC-5, jla...@highlandsniptechnology.com wrote:
On Tue, 3 Mar 2020 22:47:27 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

On Wednesday, March 4, 2020 at 12:57:56 AM UTC+1, John Larkin wrote:
On Tue, 3 Mar 2020 15:42:00 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50 ohms output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus

How much current do you need? Can you drive both ends opposite phases?

Some of the THS-series opamps might do it. Maybe use an eval board.


I would like to have an instrument, so I do not need to spend time on setup etc.

But, I had the same trail of thought, so I ordered this one as a backup solution:

https://dk.farnell.com/texas-instruments/ths4031evm/evaluation-module-amplifier/dp/3125639?CMP=i-bf9f-00001000

Cheers

Klaus

THS6022 is a beast.

There are nice tables in AoE-X, but they don't have those line drivers.

Klaus, the THS4031 has only 100 V/us slew rate. Is that going to work?

George H.

Never use THS3062.
The ADA4870 from Lasse looks like a beast!
(Did ya see the size of that thermal pad?)

Oh... I list of opamaps not to use and why would be good.

The opa124 has a voltage noise hump ~20 kHz or so... it's been too long.

George H.

A great web site would be ic-bugs.com.

--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

On Wed, 4 Mar 2020 10:52:15 +0200, Tauno Voipio
<tauno.voipio@notused.fi.invalid> wrote:

On 4.3.20 08:44, upsidedown@downunder.com wrote:
On Tue, 3 Mar 2020 15:42:00 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

40 Vpp is 14 Vrms

Tried to find gear that would do that, but they all have 50 ohms output

To drive 14Vrms into 50 ohms requires 4 W power or 0.3 Arms current.

A small HF amplifier could easily deliver that, but the problem is the
required large frequency range 1:2000, so the question is how well the
internal transmission line transformers will handle this frequency
range. At least the internal transmission line transformer ferrite
material may have to be changed.

Anyone got a link for a amplifier that can do this?

Some 1:4 or 1:9 external transmission transformers could use to feed
also loads of 5.5. 12.5, 200 or 450 ohms.


The problem lies with the low end of the frequency range, effectively
preventing the use of wideband transformers. Uncontrolled load impedance
is something a RF amplifier is not happy with, it makes it necessary
to make a far too large amplifier to cope with the surprising loads.

Indeed, the situation is getting messy with pure inductance, since the
inductive reactance would be very low at low frequencies and when
driven with a constant voltage, the current would be large. The
required power would be very large at low frequencies, unless the
inductive reactance could be tuned out with a series capacitive
reactance, but this would require switching capacitors over the
frequency range.

In reality, the coil is most likely not a pure inductance, but in
reality it has some series resistance as copper losses (for DC) and
skin losses (proportional to square root of frequency) in addition to
the frequency depended inductive reactance. The coil resistive
components (or the RL time constant) should be known before deciding
what power amplifier should be selected.

 

[Klaus Kragelund]

On Wednesday, March 4, 2020 at 7:01:43 PM UTC+1, George Herold wrote:

On Wednesday, March 4, 2020 at 11:31:06 AM UTC-5, jla...@highlandsniptechnology.com wrote:
On Wed, 4 Mar 2020 08:19:58 -0800 (PST), George Herold
ggherold@gmail.com> wrote:

On Wednesday, March 4, 2020 at 10:09:52 AM UTC-5, jla...@highlandsniptechnology.com wrote:
On Tue, 3 Mar 2020 22:47:27 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

On Wednesday, March 4, 2020 at 12:57:56 AM UTC+1, John Larkin wrote:
On Tue, 3 Mar 2020 15:42:00 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50 ohms output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus

How much current do you need? Can you drive both ends opposite phases?

Some of the THS-series opamps might do it. Maybe use an eval board.


I would like to have an instrument, so I do not need to spend time on setup etc.

But, I had the same trail of thought, so I ordered this one as a backup solution:

https://dk.farnell.com/texas-instruments/ths4031evm/evaluation-module-amplifier/dp/3125639?CMP=i-bf9f-00001000

Cheers

Klaus

THS6022 is a beast.

There are nice tables in AoE-X, but they don't have those line drivers.

Klaus, the THS4031 has only 100 V/us slew rate. Is that going to work?

George H.

Never use THS3062.
The ADA4870 from Lasse looks like a beast!
(Did ya see the size of that thermal pad?)

I have ordered it from Digikey, Lasse, thanks for the pointer

A whopping 112 USD, glad it is no me that is paying

 

[Klaus Kragelund]

On Wednesday, March 4, 2020 at 7:52:14 PM UTC+1, Joerg wrote:

On 2020-03-03 22:58, Klaus Kragelund wrote:
On Wednesday, March 4, 2020 at 2:08:26 AM UTC+1, amdx wrote:
On 3/3/2020 5:42 PM, Klaus Kragelund wrote:
Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50 ohms
output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus


Have you looked at ENI amplifiers, I think most of them are class
A. Probably expensive, here's one, 100watts, 10kHz to 12MHz. 50 ohm
output. "The 2100L will work into any load impedance. Into a short
circuit or infinite load at some phase angles it may protect itself
at power greater than 80% rated power output. Any power reflected
due to output load mismatch is absorbed in the amplifier.
Therefore, although the output impedance is 50 ohms (maximum VSWR:
2:1), the amplifier will work into any load impedance." "Continuous
operation into any load or source impedance"

https://www.theemcshop.com/dc-220-mhz-rf-amplifiers/1336-used-ei-eni-2100l-rf-power-amplifier-10-khz-12-mhz-100-watts.html



Mikek

That is a nice selection of power HF amps

I would like something with 0 ohms output, but if I am sure I will
not short it, I could just open it and short the 50 ohms resistor


I doubt there is a 50ohms resistor in the output. It's ususally a
hard-driving direct push-pull stage and a measurement bridge. This
bridge causes power to be curbed if you are trying to do things such as
driving into a short at high power.

The manual is a bit hokey, they refer to transistors without providing
the schematic.

https://www.theemcshop.com/index.php?controller=attachment&id_attachment=333

There is 50ohms, you can see it on page 130 of the repair manual PDF:

http://web.mit.edu/8.13/8.13d/manuals/agilent-33120A-function-generator-service-guide-140pages.pdf

Actually 4 parallel 100 ohms, with 4 more in series

Cheers

Klaus

 

[Michael Terrell]

On Thursday, March 5, 2020 at 8:33:55 AM UTC-5, Klaus Kragelund wrote:

On Wednesday, March 4, 2020 at 7:52:14 PM UTC+1, Joerg wrote:
On 2020-03-03 22:58, Klaus Kragelund wrote:
On Wednesday, March 4, 2020 at 2:08:26 AM UTC+1, amdx wrote:
On 3/3/2020 5:42 PM, Klaus Kragelund wrote:
Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50 ohms
output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus


Have you looked at ENI amplifiers, I think most of them are class
A. Probably expensive, here's one, 100watts, 10kHz to 12MHz. 50 ohm
output. "The 2100L will work into any load impedance. Into a short
circuit or infinite load at some phase angles it may protect itself
at power greater than 80% rated power output. Any power reflected
due to output load mismatch is absorbed in the amplifier.
Therefore, although the output impedance is 50 ohms (maximum VSWR:
2:1), the amplifier will work into any load impedance." "Continuous
operation into any load or source impedance"

https://www.theemcshop.com/dc-220-mhz-rf-amplifiers/1336-used-ei-eni-2100l-rf-power-amplifier-10-khz-12-mhz-100-watts.html



Mikek

That is a nice selection of power HF amps

I would like something with 0 ohms output, but if I am sure I will
not short it, I could just open it and short the 50 ohms resistor


I doubt there is a 50ohms resistor in the output. It's ususally a
hard-driving direct push-pull stage and a measurement bridge. This
bridge causes power to be curbed if you are trying to do things such as
driving into a short at high power.

The manual is a bit hokey, they refer to transistors without providing
the schematic.

https://www.theemcshop.com/index.php?controller=attachment&id_attachment=333

There is 50ohms, you can see it on page 130 of the repair manual PDF:

http://web.mit.edu/8.13/8.13d/manuals/agilent-33120A-function-generator-service-guide-140pages.pdf

Actually 4 parallel 100 ohms, with 4 more in series

Since it was designed to drive 50 Ohm loads, it has to be a 50 Ohm source. If it wasn't, it would be useless to test filter circuits designed for 50 ohms. That is not the same as a HF Amplifier. The amplifier would waste 50% of its output power into a design like that. You need a design that transfers maximum power into your 50 Ohm load. Impedance matching is more important in receiver designs, where you sometimes use a 3dB pad to improve the impedance matching around a mixer circuit. You lose 3dB system gain, but you improve the overall signal quality.

 

[Clifford Heath]

On 6/3/20 12:41 am, Klaus Kragelund wrote:

On Wednesday, March 4, 2020 at 7:01:43 PM UTC+1, George Herold wrote:
On Wednesday, March 4, 2020 at 11:31:06 AM UTC-5, jla...@highlandsniptechnology.com wrote:
On Wed, 4 Mar 2020 08:19:58 -0800 (PST), George Herold
ggherold@gmail.com> wrote:

On Wednesday, March 4, 2020 at 10:09:52 AM UTC-5, jla...@highlandsniptechnology.com wrote:
On Tue, 3 Mar 2020 22:47:27 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

On Wednesday, March 4, 2020 at 12:57:56 AM UTC+1, John Larkin wrote:
On Tue, 3 Mar 2020 15:42:00 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50 ohms output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus

How much current do you need? Can you drive both ends opposite phases?

Some of the THS-series opamps might do it. Maybe use an eval board.


I would like to have an instrument, so I do not need to spend time on setup etc.

But, I had the same trail of thought, so I ordered this one as a backup solution:

https://dk.farnell.com/texas-instruments/ths4031evm/evaluation-module-amplifier/dp/3125639?CMP=i-bf9f-00001000

Cheers

Klaus

THS6022 is a beast.

There are nice tables in AoE-X, but they don't have those line drivers.

Klaus, the THS4031 has only 100 V/us slew rate. Is that going to work?

George H.

Never use THS3062.
The ADA4870 from Lasse looks like a beast!
(Did ya see the size of that thermal pad?)

I have ordered it from Digikey, Lasse, thanks for the pointer

A whopping 112 USD, glad it is no me that is paying

That's the EVB. The chip is <$20 in single units. What a monster!

 

[Joerg]

On 2020-03-05 05:33, Klaus Kragelund wrote:

On Wednesday, March 4, 2020 at 7:52:14 PM UTC+1, Joerg wrote:
On 2020-03-03 22:58, Klaus Kragelund wrote:
On Wednesday, March 4, 2020 at 2:08:26 AM UTC+1, amdx wrote:
On 3/3/2020 5:42 PM, Klaus Kragelund wrote:
Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50 ohms
output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus


Have you looked at ENI amplifiers, I think most of them are class
A. Probably expensive, here's one, 100watts, 10kHz to 12MHz. 50 ohm
output. "The 2100L will work into any load impedance. Into a short
circuit or infinite load at some phase angles it may protect itself
at power greater than 80% rated power output. Any power reflected
due to output load mismatch is absorbed in the amplifier.
Therefore, although the output impedance is 50 ohms (maximum VSWR:
2:1), the amplifier will work into any load impedance." "Continuous
operation into any load or source impedance"

https://www.theemcshop.com/dc-220-mhz-rf-amplifiers/1336-used-ei-eni-2100l-rf-power-amplifier-10-khz-12-mhz-100-watts.html



Mikek

That is a nice selection of power HF amps

I would like something with 0 ohms output, but if I am sure I will
not short it, I could just open it and short the 50 ohms resistor


I doubt there is a 50ohms resistor in the output. It's ususally a
hard-driving direct push-pull stage and a measurement bridge. This
bridge causes power to be curbed if you are trying to do things such as
driving into a short at high power.

The manual is a bit hokey, they refer to transistors without providing
the schematic.

https://www.theemcshop.com/index.php?controller=attachment&id_attachment=333

There is 50ohms, you can see it on page 130 of the repair manual PDF:

http://web.mit.edu/8.13/8.13d/manuals/agilent-33120A-function-generator-service-guide-140pages.pdf

Actually 4 parallel 100 ohms, with 4 more in series

Yes, but that is a function generator, not the big EMC amp. For 40Vpp
over the required frequency range into a possibly iffy load you need
something big.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John S]

On 3/6/2020 11:56 AM, amdx wrote:

On 3/5/2020 3:37 PM, Clifford Heath wrote:
On 6/3/20 12:41 am, Klaus Kragelund wrote:
On Wednesday, March 4, 2020 at 7:01:43 PM UTC+1, George Herold wrote:
On Wednesday, March 4, 2020 at 11:31:06 AM UTC-5,
jla...@highlandsniptechnology.com wrote:
On Wed, 4 Mar 2020 08:19:58 -0800 (PST), George Herold
ggherold@gmail.com> wrote:

On Wednesday, March 4, 2020 at 10:09:52 AM UTC-5,
jla...@highlandsniptechnology.com wrote:
On Tue, 3 Mar 2020 22:47:27 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

On Wednesday, March 4, 2020 at 12:57:56 AM UTC+1, John Larkin
wrote:
On Tue, 3 Mar 2020 15:42:00 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50
ohms output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus

How much current do you need? Can you drive both ends opposite
phases?

Some of the THS-series opamps might do it. Maybe use an eval
board.


I would like to have an instrument, so I do not need to spend
time on setup etc.

But, I had the same trail of thought, so I ordered this one as a
backup solution:

https://dk.farnell.com/texas-instruments/ths4031evm/evaluation-module-amplifier/dp/3125639?CMP=i-bf9f-00001000


Cheers

Klaus

THS6022 is a beast.

There are nice tables in AoE-X, but they don't have those line
drivers.

Klaus, the THS4031 has only 100 V/us slew rate.  Is that going to
work?

George H.

Never use THS3062.
The ADA4870 from Lasse looks like a beast!
(Did ya see the size of that thermal pad?)

I have ordered it from Digikey, Lasse, thanks for the pointer

A whopping 112 USD, glad it is no me that is paying

That's the EVB. The chip is <$20 in single units. What a monster!



 Why is the DK Farnell board so different then the Mouser Board?

https://dk.farnell.com/texas-instruments/ths4031evm/evaluation-module-amplifier/dp/3125639?CMP=i-bf9f-00001000



https://www.mouser.com/ProductDetail/Texas-Instruments/THS4031EVM?qs=rXqtSHp76q75uuzzLpelOA%3D%3D

 Get it while you can, 1 in stock.

                                           Mikek

Mouser says: Images are for reference only
See Product Specifications

 

[amdx]

On 3/5/2020 3:37 PM, Clifford Heath wrote:

On 6/3/20 12:41 am, Klaus Kragelund wrote:
On Wednesday, March 4, 2020 at 7:01:43 PM UTC+1, George Herold wrote:
On Wednesday, March 4, 2020 at 11:31:06 AM UTC-5,
jla...@highlandsniptechnology.com wrote:
On Wed, 4 Mar 2020 08:19:58 -0800 (PST), George Herold
ggherold@gmail.com> wrote:

On Wednesday, March 4, 2020 at 10:09:52 AM UTC-5,
jla...@highlandsniptechnology.com wrote:
On Tue, 3 Mar 2020 22:47:27 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

On Wednesday, March 4, 2020 at 12:57:56 AM UTC+1, John Larkin wrote:
On Tue, 3 Mar 2020 15:42:00 -0800 (PST), Klaus Kragelund
klauskvik@hotmail.com> wrote:

Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50
ohms output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus

How much current do you need? Can you drive both ends opposite
phases?

Some of the THS-series opamps might do it. Maybe use an eval board.


I would like to have an instrument, so I do not need to spend
time on setup etc.

But, I had the same trail of thought, so I ordered this one as a
backup solution:

https://dk.farnell.com/texas-instruments/ths4031evm/evaluation-module-amplifier/dp/3125639?CMP=i-bf9f-00001000


Cheers

Klaus

THS6022 is a beast.

There are nice tables in AoE-X, but they don't have those line
drivers.

Klaus, the THS4031 has only 100 V/us slew rate.  Is that going to
work?

George H.

Never use THS3062.
The ADA4870 from Lasse looks like a beast!
(Did ya see the size of that thermal pad?)

I have ordered it from Digikey, Lasse, thanks for the pointer

A whopping 112 USD, glad it is no me that is paying

That's the EVB. The chip is <$20 in single units. What a monster!

Why is the DK Farnell board so different then the Mouser Board?

https://dk.farnell.com/texas-instruments/ths4031evm/evaluation-module-amplifier/dp/3125639?CMP=i-bf9f-00001000

https://www.mouser.com/ProductDetail/Texas-Instruments/THS4031EVM?qs=rXqtSHp76q75uuzzLpelOA%3D%3D
Get it while you can, 1 in stock.

Mikek

 

[Metabastler]

Am 04.03.2020 um 00:42 schrieb Klaus Kragelund:

Hi

I need to drive a coil with 40Vpp at 10kHz to 20MHz for a test

Tried to find gear that would do that, but they all have 50 ohms output

Anyone got a link for a amplifier that can do this?

Thanks

Klaus

www.beak-electronic.de