Re: LF: Si5351A syntehsiser able to fire a FET driver chip directly??

[Andy Talbot <andy.g4jnt@gmail.com>]

Seems an odd choice of driver chip.  A high/low side driver used in a non-bootstrapped mode to drive two low-side FETs 

How about one of the normal FET driver chips - picking out one I've used in the past, the MCP14E 3/4/5 family.   Logic level input, spec. Logic '0' max 1.3V, Logic '1' min 2.4V.   So bias half way and your 2.2V swing takes it into the valid range.

They three types are inverting, non inverting, and one of each in a package

Andy  G4JNT

On 1 January 2018 at 10:38, Chris Wilson <dead.fets@gmail.com> wrote:

Hello  LF'ers, and a happy and healthy New Year to you all.

I use my U3S QRP Labs exciter to drive a PA on 137kHz, and it works
fine. Hans, the designer, made changes allowing a 180 degree out of
phase pair of signals to come from the Si5351A synthesizer chip with
the intention of this being able to drive a push pull Class D FET
driver chip directly without a X2 signal being divided and split by a
preceding IC, please see original and simplified circuits below. I
tried this but it appears the circa 2.2V outputs of the Si5351A chip
are not sufficient to drive the inputs of the IR2110 FET driver.

Any ideas please?     Thanks.

 Original  PA  circuit (works fine with "normal" U3S driving the 74F74
 direct with CLK0 output):

http://www.gatesgarth.com/amp.jpg



Modded  amp  circuit (simplified in the hope of building with one less
IC):

http://www.gatesgarth.com/amp-modded.jpg



IR2110FET driver specs:

http://www.gatesgarth.com/IR2110.pdf



74F74 IC specs:

http://www.gatesgarth.com/74F74.pdf


U3S schematic:

http://www.gatesgarth.com/u3s-schematic.jpg




--
Best regards,
 Chris                          mailto:dead.fets@gmail.com