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ADA4891 op amp...

B

bitrex

Guest
What\'s wrong with this picture? (from LTSpice\'s test fixtures)

<https://imgur.com/a/VC5TL3w>
 
C

Clive Arthur

Guest
On 30/10/2020 02:51, bitrex wrote:
What\'s wrong with this picture? (from LTSpice\'s test fixtures)

https://imgur.com/a/VC5TL3w
It\'s an ugly way of drawing the V- supply, but it should work?

--
Cheers
Clive
 
S

server

Guest
On Fri, 30 Oct 2020 08:52:17 +0000, Clive Arthur
<clive@nowaytoday.co.uk> wrote:

On 30/10/2020 02:51, bitrex wrote:
What\'s wrong with this picture? (from LTSpice\'s test fixtures)

https://imgur.com/a/VC5TL3w

It\'s an ugly way of drawing the V- supply, but it should work?
The amp is only rated for a 5 volt supply.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
B

bitrex

Guest
On 10/30/2020 10:45 AM, jlarkin@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 08:52:17 +0000, Clive Arthur
clive@nowaytoday.co.uk> wrote:

On 30/10/2020 02:51, bitrex wrote:
What\'s wrong with this picture? (from LTSpice\'s test fixtures)

https://imgur.com/a/VC5TL3w

It\'s an ugly way of drawing the V- supply, but it should work?

The amp is only rated for a 5 volt supply.
Yes, and yet it works in the test fixture anyway, but only if you
configure it as a non-inverting amp as they\'ve done.

They copy-pasted and didn\'t notice because of their own lousy models.
Sure saves time that way!
 
C

Clive Arthur

Guest
On 30/10/2020 14:45, jlarkin@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 08:52:17 +0000, Clive Arthur
clive@nowaytoday.co.uk> wrote:

On 30/10/2020 02:51, bitrex wrote:
What\'s wrong with this picture? (from LTSpice\'s test fixtures)

https://imgur.com/a/VC5TL3w

It\'s an ugly way of drawing the V- supply, but it should work?

The amp is only rated for a 5 volt supply.
That can\'t be right - op-amps work from +/-15V supplies!

I was a bit surprised not long ago when Googling \"high voltage op-amps\"
that the meaning has changed somewhat.

--
Cheers
Clive
 
J

John Larkin

Guest
On Fri, 30 Oct 2020 19:54:56 +0000, Clive Arthur
<clive@nowaytoday.co.uk> wrote:

On 30/10/2020 14:45, jlarkin@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 08:52:17 +0000, Clive Arthur
clive@nowaytoday.co.uk> wrote:

On 30/10/2020 02:51, bitrex wrote:
What\'s wrong with this picture? (from LTSpice\'s test fixtures)

https://imgur.com/a/VC5TL3w

It\'s an ugly way of drawing the V- supply, but it should work?

The amp is only rated for a 5 volt supply.


That can\'t be right - op-amps work from +/-15V supplies!

I was a bit surprised not long ago when Googling \"high voltage op-amps\"
that the meaning has changed somewhat.
High frequency and high slew rate are flexible terms too.

Lately I use a lot of OPA197. It\'s good to 36 volts, rrio, 10 MHz, and
has pA bias current. Makes a pretty good comparator too.

Here\'s my 400 volt opamp:

https://www.dropbox.com/s/w8px8z9mf64wpc9/HVamp.JPG?raw=1

It\'s not very fast.
 
B

bitrex

Guest
On 10/30/2020 4:50 PM, John Larkin wrote:
On Fri, 30 Oct 2020 19:54:56 +0000, Clive Arthur
clive@nowaytoday.co.uk> wrote:

On 30/10/2020 14:45, jlarkin@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 08:52:17 +0000, Clive Arthur
clive@nowaytoday.co.uk> wrote:

On 30/10/2020 02:51, bitrex wrote:
What\'s wrong with this picture? (from LTSpice\'s test fixtures)

https://imgur.com/a/VC5TL3w

It\'s an ugly way of drawing the V- supply, but it should work?

The amp is only rated for a 5 volt supply.


That can\'t be right - op-amps work from +/-15V supplies!

I was a bit surprised not long ago when Googling \"high voltage op-amps\"
that the meaning has changed somewhat.

High frequency and high slew rate are flexible terms too.

Lately I use a lot of OPA197. It\'s good to 36 volts, rrio, 10 MHz, and
has pA bias current. Makes a pretty good comparator too.

Here\'s my 400 volt opamp:

https://www.dropbox.com/s/w8px8z9mf64wpc9/HVamp.JPG?raw=1

It\'s not very fast.
I\'m doing an isolated composite video switch with a output line driver:

<https://www.dropbox.com/s/tah8fc6tvqicik4/video_switch.PNG?dl=0>

Don\'t have much experience with video amps so this is a first attempt.
The LT1723 looks promising, with a LT1203 as the switch.

<https://www.dropbox.com/s/f4qs1or7q3zqg4y/video_switch.PNG?dl=0>

if the LT1723 had enables I could probably eliminate the switch IC but I
haven\'t found a dual with enables with as large bandwidth and drive
current that makes much dif in the parts cost.

I can probably just cap couple the output if the transformer doesn\'t
give enough low frequency response for composite, no way to actively
compensate it like on the input side.
 
B

bitrex

Guest
On 10/30/2020 6:07 PM, bitrex wrote:
On 10/30/2020 4:50 PM, John Larkin wrote:
On Fri, 30 Oct 2020 19:54:56 +0000, Clive Arthur
clive@nowaytoday.co.uk> wrote:

On 30/10/2020 14:45, jlarkin@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 08:52:17 +0000, Clive Arthur
clive@nowaytoday.co.uk> wrote:

On 30/10/2020 02:51, bitrex wrote:
What\'s wrong with this picture? (from LTSpice\'s test fixtures)

https://imgur.com/a/VC5TL3w

It\'s an ugly way of drawing the V- supply, but it should work?

The amp is only rated for a 5 volt supply.


That can\'t be right - op-amps work from +/-15V supplies!

I was a bit surprised not long ago when Googling \"high voltage op-amps\"
that the meaning has changed somewhat.

High frequency and high slew rate are flexible terms too.

Lately I use a lot of OPA197. It\'s good to 36 volts, rrio, 10 MHz, and
has pA bias current. Makes a pretty good comparator too.

Here\'s my 400 volt opamp:

https://www.dropbox.com/s/w8px8z9mf64wpc9/HVamp.JPG?raw=1

It\'s not very fast.



I\'m doing an isolated composite video switch with a output line driver:

https://www.dropbox.com/s/tah8fc6tvqicik4/video_switch.PNG?dl=0

Don\'t have much experience with video amps so this is a first attempt.
The LT1723 looks promising, with a LT1203 as the switch.

https://www.dropbox.com/s/f4qs1or7q3zqg4y/video_switch.PNG?dl=0

if the LT1723 had enables I could probably eliminate the switch IC but I
haven\'t found a dual with enables with as large bandwidth and drive
current that makes much dif in the parts cost.

I can probably just cap couple the output if the transformer doesn\'t
give enough low frequency response for composite, no way to actively
compensate it like on the input side.
(please disregard second dead link)
 
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