Gerhard Hoffmann writes:
> Have you seen the new THS3491 ? LMH6702 on steroids.
>
> This one begs to be designed into new distribution amplifiers:
>
> Everything from DC / 1pps to a few 100 MHz into 50 Ohms, without any
> changes.
While everybody is looking for opamps with even higher GBW
I'd suggest that if you wish to use a DIP or SO-8 version of a single
CFA, and attain maximum BW and flatness, on a regular board, it should
be mounted on the ground plane side, and the feedback resistor should be
underneath on the opposite surface, directly between the output and
inverting
On Sat, 15 Dec 2018 19:02:30 +0200
Anders Wallin wrote:
> That got rid of the self-oscillation - but now I am left with severe (16 dB
> @ 230 MHz) gain-peaking! (see attached figure)
Could it be, that the stray capacitance to ground of the non-inverted
input is now too big? You increased the
Am 17.12.18 um 16:22 schrieb Anders Wallin:
Stylish dead-bug! ;)
On my board I increased Rf/Rg to 4k7, to get rid of the gain-peaking.
With 4k7 resistors I see +20 dBc/Hz worse phase-noise with the THS3491
compared to LMH6702 :( (image attached)
If noise power scales with the resistors then it
> Stylish dead-bug! ;)
> On my board I increased Rf/Rg to 4k7, to get rid of the gain-peaking.
> With 4k7 resistors I see +20 dBc/Hz worse phase-noise with the THS3491
> compared to LMH6702 :( (image attached)
> If noise power scales with the resistors then it explains about 4k7/200R =
> 14 dB,
> So the THS3491 is an LMH6702 replacement except
> for a slightly elevated noise floor. Why would
> anyone not want to use the LMH6702? What does
> the THS3491 have going for it?
Power output is what caught my eye. After the loss in the series termination,
the LMH6702 struggles to put out
...@lists.febo.com] On Behalf Of
Anders Wallin
Sent: Saturday, December 15, 2018 9:03 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] new op amp for distribution amplifiers
Hello Gerhard, everyone,
I made a test using the THS3491 on a slightly modified PCB from my &quo
> Has anybody tried the AD8003 (triple video line driver amplifier) for use
as
> distribution amplifiers? It looks to me like this part might be a decent
> choice...
I don't have any NF or residual PN numbers handy for the triple-amp
versions, but the single-amplifier part from the same family
Has anybody tried the AD8003 (triple video line driver amplifier) for use as
distribution amplifiers? It looks to me like this part might be a decent
choice.
On caveat, however: don't succumb to the temptation to reduce the circuit
bandwidth by putting a capacitor across the feedback resistor-
Have you seen the new THS3491 ? LMH6702 on steroids.
This one begs to be designed into new distribution amplifiers:
Everything from DC / 1pps to a few 100 MHz into 50 Ohms, without any
changes.
(the usual gain = 2, 50R/50R out design)
rise / fall 1.3 ns for 10V step
slew rate 8V / ns
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