bitrex = a complete dope wrote:

==================================
 Phil Allison wrote:

>>
> > ** The uA733 fits your spec, Digikey have lots in various paks inc SMD.
> > 
> > The data sheet says it hails from 1970, so maybe a bit old hat for you.
> > 
> > I know it cos there are a couple in my 50MHz dual trace scope 
> > providing most of the vertical gain.
>
.
> 
> Amazing it's still being made and in relatively large quantity,

** Must be very special - right ? 

 
> problem is it's not really suitable for use as a buffer amp/line driving.
>

** Read you own post - fuckhead. 

 What does it say about buffering a low impedance? 

 ( Wot a vile, pathetic cretin ) 


.....  Phil 

On 2020-10-06, bitrex <user@example.net> wrote:
> On 10/6/2020 5:32 AM, bitrex wrote:
>
> Dual-boot Linux and Windows can't figure out what time it is :(

Set both to use the hardware clock as GMT

-- 
  Jasen.

On 10/5/2020 11:48 PM, bitrex wrote:
> Looking for a recommendation for a voltage-feedback op amp suitable for 
> buffering/amplifying composite video signals, not a portable application 
> so +5/-5 supply is OK. An amp that can drive 75 ohms directly is nice 
> but not required I can always add a buffer. Something around $1.50 in 
> quantity?
> 
> There's a lot to choose from and not everything lists differential gain 
> and differential phase up-front so a recommendation would be nice

Neat, Linear/AD actually makes the thing I need all integrated into one 
chip, a 3-input video multiplexer + line driver:

<https://www.mouser.com/ProductDetail/Analog-Devices/LT6559CUDPBF?qs=hVkxg5c3xu%2FSkXiqmdItxQ%3D%3D>

not much more than $1 in quantity, surprisingly.

On 10/6/2020 12:22 AM, Phil Allison wrote:
> bitrex wrote:
> 
> ===============--
>> Looking for a recommendation for a voltage-feedback op amp suitable for
>> buffering/amplifying composite video signals, not a portable application
>> so +5/-5 supply is OK. An amp that can drive 75 ohms directly is nice
>> but not required I can always add a buffer. Something around $1.50 in
>> quantity?
>>
>>
> ** The uA733 fits your spec, Digikey have lots in various paks inc SMD.
> 
> The data sheet says it hails from 1970, so maybe a bit old hat for you.
> 
> I know it cos there are a couple in my 50MHz dual trace scope providing most of the vertical gain.
> 
> 
> ....  Phil
> 
>   
> 
> 

Wow, magnetic tape or disc-file systems. I'm picturing one of those big 
cabinets with spinning tape mass storage for mainframe computers.

Amazing it's still being made and in relatively large quantity, even. 
All transistors inside look to be NPN, maybe the design dates from the 
time when it wasn't cheap to put PNPs on an IC. problem is it's not 
really suitable for use as a buffer amp/line driving.

I just noticed NJR seems to make a bespoke chip for that "and is 
suitable for low power design on downsizing of Car camera and CCTV."

<https://www.mouser.com/datasheet/2/294/NJM2561_E-1375659.pdf>

and includes the 6dB voltage gain to compensate for the termination 
divider action.

The application is something like that, buffering the output of a video 
multiplexer into an isolation transformer. There's an EDN article on how 
to set the output impedance using feedback rather than in-line 
resistance but needs an op-amp type of amplifier that can have arbitrary 
gain:

<https://www.edn.com/save-3-db-of-output-power-using-feedback-to-set-the-output-impedance/>

On 10/6/2020 5:32 AM, bitrex wrote:

Dual-boot Linux and Windows can't figure out what time it is :(

bitrex wrote:

===============--
> Looking for a recommendation for a voltage-feedback op amp suitable for 
> buffering/amplifying composite video signals, not a portable application 
> so +5/-5 supply is OK. An amp that can drive 75 ohms directly is nice 
> but not required I can always add a buffer. Something around $1.50 in 
> quantity?
> 
>
** The uA733 fits your spec, Digikey have lots in various paks inc SMD.

The data sheet says it hails from 1970, so maybe a bit old hat for you.

I know it cos there are a couple in my 50MHz dual trace scope providing most of the vertical gain. 


....  Phil

 

On 10/5/2020 11:48 PM, bitrex wrote:
> Looking for a recommendation for a voltage-feedback op amp suitable for 
> buffering/amplifying composite video signals, not a portable application 
> so +5/-5 supply is OK. An amp that can drive 75 ohms directly is nice 
> but not required I can always add a buffer. Something around $1.50 in 
> quantity?
> 
> There's a lot to choose from and not everything lists differential gain 
> and differential phase up-front so a recommendation would be nice

Differential gain and phase error, rather

Looking for a recommendation for a voltage-feedback op amp suitable for 
buffering/amplifying composite video signals, not a portable application 
so +5/-5 supply is OK. An amp that can drive 75 ohms directly is nice 
but not required I can always add a buffer. Something around $1.50 in 
quantity?

There's a lot to choose from and not everything lists differential gain 
and differential phase up-front so a recommendation would be nice