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Groups > sci.electronics.design > #518858 > unrolled thread

tiny board

Started byJohn Larkin <jjlarkin@highlandtechnology.com>
First post2018-10-09 20:22 -0700
Last post2018-10-10 07:38 -0700
Articles 17 — 6 participants

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Contents

  tiny board John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-09 20:22 -0700
    Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-10 06:30 +0000
      Re: tiny board tabbypurr@gmail.com - 2018-10-10 02:39 -0700
        Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-10 14:08 +0000
          Re: tiny board tabbypurr@gmail.com - 2018-10-10 08:34 -0700
      Re: tiny board DecadentLinuxUserNumeroUno@decadence.org - 2018-10-10 09:54 +0000
      Re: tiny board John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-10 07:43 -0700
      Re: tiny board John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-10 11:12 -0700
        Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-10 19:12 +0000
          Re: tiny board John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-10 12:26 -0700
            Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-12 17:57 +0000
              Re: tiny board John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-12 12:55 -0700
                Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-13 06:59 +0000
                  Re: tiny board John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-13 08:54 -0700
                    Re: tiny board <698839253X6D445TD@nospam.org> - 2018-10-13 18:19 +0000
    Re: tiny board George Herold <gherold@teachspin.com> - 2018-10-10 06:40 -0700
      Re: tiny board John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-10 07:38 -0700

#518858 — tiny board

FromJohn Larkin <jjlarkin@highlandtechnology.com>
Date2018-10-09 20:22 -0700
Subjecttiny board
Message-ID<0frqrdhr318tkcq2psfqpfj4e36eafcap8@4ax.com>

This has two of the tiny EPC BGA GaN fets and a gate driver. It can be
used as a throw-away component on other boards.

https://www.dropbox.com/s/k5wvzrcwodk0scf/T852C.JPG?raw=1

This is the dual-fet high-current version of the thing I posted a
while back. The fets are in parallel but the drains come out to
separate mouse-bites and test points so we can test everything
properly.

Here's the test fixture.

https://www.dropbox.com/s/27ee1vspd4g9h1n/T852_Tester.JPG?raw=1


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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#518859

From<698839253X6D445TD@nospam.org>
Date2018-10-10 06:30 +0000
Message-ID<ppk6an$1vqi$1@gioia.aioe.org>
In reply to#518858
John Larkin
>
>This has two of the tiny EPC BGA GaN fets and a gate driver. It can be
>used as a throw-away component on other boards.
>
>https://www.dropbox.com/s/k5wvzrcwodk0scf/T852C.JPG?raw=1

The question is: 
 'What happens when there are more holes than matter'


>This is the dual-fet high-current version of the thing I posted a
>while back. The fets are in parallel but the drains come out to
>separate mouse-bites and test points so we can test everything
>properly.
>
>Here's the test fixture.
>
>https://www.dropbox.com/s/27ee1vspd4g9h1n/T852_Tester.JPG?raw=1

2 resistors?
1 390 Ohm (drain I suppose)
the other one hard to tell, 470 maybe.

Missing : circuit diagram.

Real gold detected!

LOL

I would just use a piece of 10 cent veroboard,
as the long wires and high resistor values give away it is not really RF?
+5 not decoupled close to ground.

Is it a curve tracer?

????

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#518863

Fromtabbypurr@gmail.com
Date2018-10-10 02:39 -0700
Message-ID<db26434a-b723-45cb-9d90-7799b205da66@googlegroups.com>
In reply to#518859
On Wednesday, 10 October 2018 07:30:52 UTC+1, 69883925...@nospam.org  wrote:
> John Larkin
> >
> >This has two of the tiny EPC BGA GaN fets and a gate driver. It can be
> >used as a throw-away component on other boards.
> >
> >https://www.dropbox.com/s/k5wvzrcwodk0scf/T852C.JPG?raw=1
> 
> The question is: 
>  'What happens when there are more holes than matter'
> 
> 
> >This is the dual-fet high-current version of the thing I posted a
> >while back. The fets are in parallel but the drains come out to
> >separate mouse-bites and test points so we can test everything
> >properly.
> >
> >Here's the test fixture.
> >
> >https://www.dropbox.com/s/27ee1vspd4g9h1n/T852_Tester.JPG?raw=1
> 
> 2 resistors?
> 1 390 Ohm (drain I suppose)
> the other one hard to tell, 470 maybe.
> 
> Missing : circuit diagram.
> 
> Real gold detected!
> 
> LOL
> 
> I would just use a piece of 10 cent veroboard,
> as the long wires and high resistor values give away it is not really RF?
> +5 not decoupled close to ground.
> 
> Is it a curve tracer?
> 
> ????

vero doesn't have the heat transfer


NT

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#518873

From<698839253X6D445TD@nospam.org>
Date2018-10-10 14:08 +0000
Message-ID<ppl152$1fna$1@gioia.aioe.org>
In reply to#518863
On a sunny day (Wed, 10 Oct 2018 02:39:00 -0700 (PDT)) it happened
tabbypurr@gmail.com wrote in
<db26434a-b723-45cb-9d90-7799b205da66@googlegroups.com>:

>On Wednesday, 10 October 2018 07:30:52 UTC+1, 69883925...@nospam.org  wrote:
>> John Larkin
>> >
>> >This has two of the tiny EPC BGA GaN fets and a gate driver. It can be
>> >used as a throw-away component on other boards.
>> >
>> >https://www.dropbox.com/s/k5wvzrcwodk0scf/T852C.JPG?raw=1
>> 
>> The question is: 
>>  'What happens when there are more holes than matter'
>> 
>> 
>> >This is the dual-fet high-current version of the thing I posted a
>> >while back. The fets are in parallel but the drains come out to
>> >separate mouse-bites and test points so we can test everything
>> >properly.
>> >
>> >Here's the test fixture.
>> >
>> >https://www.dropbox.com/s/27ee1vspd4g9h1n/T852_Tester.JPG?raw=1
>> 
>> 2 resistors?
>> 1 390 Ohm (drain I suppose)
>> the other one hard to tell, 470 maybe.
>> 
>> Missing : circuit diagram.
>> 
>> Real gold detected!
>> 
>> LOL
>> 
>> I would just use a piece of 10 cent veroboard,
>> as the long wires and high resistor values give away it is not really RF?
>> +5 not decoupled close to ground.
>> 
>> Is it a curve tracer?
>> 
>> ????
>
>vero doesn't have the heat transfer

Heat transfer from 5V in a 390 Ohm resistor????

Ya musta beee kidding
 

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#518880

Fromtabbypurr@gmail.com
Date2018-10-10 08:34 -0700
Message-ID<0c7b8aa9-c623-41dd-8f22-0481d9f558a1@googlegroups.com>
In reply to#518873
On Wednesday, 10 October 2018 15:08:42 UTC+1, 69883925...@nospam.org  wrote:
> On a sunny day (Wed, 10 Oct 2018 02:39:00 -0700 (PDT)) it happened
> tabbypurr wrote in
> <db26434a-b723-45cb-9d90-7799b205da66@googlegroups.com>:
> 
> >On Wednesday, 10 October 2018 07:30:52 UTC+1, 69883925...@nospam.org  wrote:
> >> John Larkin
> >> >
> >> >This has two of the tiny EPC BGA GaN fets and a gate driver. It can be
> >> >used as a throw-away component on other boards.
> >> >
> >> >https://www.dropbox.com/s/k5wvzrcwodk0scf/T852C.JPG?raw=1
> >> 
> >> The question is: 
> >>  'What happens when there are more holes than matter'
> >> 
> >> 
> >> >This is the dual-fet high-current version of the thing I posted a
> >> >while back. The fets are in parallel but the drains come out to
> >> >separate mouse-bites and test points so we can test everything
> >> >properly.
> >> >
> >> >Here's the test fixture.
> >> >
> >> >https://www.dropbox.com/s/27ee1vspd4g9h1n/T852_Tester.JPG?raw=1
> >> 
> >> 2 resistors?
> >> 1 390 Ohm (drain I suppose)
> >> the other one hard to tell, 470 maybe.
> >> 
> >> Missing : circuit diagram.
> >> 
> >> Real gold detected!
> >> 
> >> LOL
> >> 
> >> I would just use a piece of 10 cent veroboard,
> >> as the long wires and high resistor values give away it is not really RF?
> >> +5 not decoupled close to ground.
> >> 
> >> Is it a curve tracer?
> >> 
> >> ????
> >
> >vero doesn't have the heat transfer
> 
> Heat transfer from 5V in a 390 Ohm resistor????
> 
> Ya musta beee kidding

I've no idea what you mean there


NT

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#518865

FromDecadentLinuxUserNumeroUno@decadence.org
Date2018-10-10 09:54 +0000
Message-ID<ppki8o$kfn$1@gioia.aioe.org>
In reply to#518859
<698839253X6D445TD@nospam.org> wrote in news:ppk6an$1vqi$1@gioia.aioe.org:

> The question is: 
>  'What happens when there are more holes than matter'
> 

The answer is:  One gets better heat transfer numbers.

  That is an idea for a polymer board though.

  Take gold rivets (FLOABW), and make the interconnections with gold wire, 
then 3D print the PCB over the rivet/wire assembly.  No more fiberglass.
There would be applications for this.  It is like when one pots the HV 
section of an HVPS, but more precise and more planar.

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#518875

FromJohn Larkin <jjlarkin@highlandtechnology.com>
Date2018-10-10 07:43 -0700
Message-ID<ho3srd5vq37ikhi590vfm6coonneta64jl@4ax.com>
In reply to#518859
On Wed, 10 Oct 2018 06:30:47 GMT, <698839253X6D445TD@nospam.org>
wrote:

>John Larkin
>>
>>This has two of the tiny EPC BGA GaN fets and a gate driver. It can be
>>used as a throw-away component on other boards.
>>
>>https://www.dropbox.com/s/k5wvzrcwodk0scf/T852C.JPG?raw=1
>
>The question is: 
> 'What happens when there are more holes than matter'

The GaN fets are tiny and will get hot. The board is 32 mils thick and
2 oz copper on both sides, and the vias help spread the heat.

At a given current, two fets in parallel result in less than 1/4 the
dissipation per fet compared to using one.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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#518889

FromJohn Larkin <jjlarkin@highland_snip_technology.com>
Date2018-10-10 11:12 -0700
Message-ID<h7esrdl6ni0gbf3m0iutjn6uambclocetc@4ax.com>
In reply to#518859
On Wed, 10 Oct 2018 06:30:47 GMT, <698839253X6D445TD@nospam.org>
wrote:

>John Larkin
>>
>>This has two of the tiny EPC BGA GaN fets and a gate driver. It can be
>>used as a throw-away component on other boards.
>>
>>https://www.dropbox.com/s/k5wvzrcwodk0scf/T852C.JPG?raw=1
>
>The question is: 
> 'What happens when there are more holes than matter'
>
>
>>This is the dual-fet high-current version of the thing I posted a
>>while back. The fets are in parallel but the drains come out to
>>separate mouse-bites and test points so we can test everything
>>properly.
>>
>>Here's the test fixture.
>>
>>https://www.dropbox.com/s/27ee1vspd4g9h1n/T852_Tester.JPG?raw=1
>
>2 resistors?
>1 390 Ohm (drain I suppose)
>the other one hard to tell, 470 maybe.
>
>Missing : circuit diagram.
>

This is my hack for testing the dual-fet board:

https://www.dropbox.com/s/fahyykwsjerh10y/Z440_C.JPG?raw=1

This will work for the old single-fet version too.



-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

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

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#518892

From<698839253X6D445TD@nospam.org>
Date2018-10-10 19:12 +0000
Message-ID<ppliub$hb4$1@gioia.aioe.org>
In reply to#518889
John Larkin wrote
>This is my hack for testing the dual-fet board:
>
>https://www.dropbox.com/s/fahyykwsjerh10y/Z440_C.JPG?raw=1
>
>This will work for the old single-fet version too.

OK, that will give rise-time depending on circuit wiring - and scope lead capacitance I suppose.
If you were to drive it with a ramp on one scope channel,
it could give the pinch of point / transfer. 

I don't know this transistor, suppose it is very fast,
the chip on that mouse byte board only shows 'LXE'

I have some Sirenza VCOs that use a similar mouse byte PCB,
have not had any problems with that in prototyping

Been coding a Linux test program for the LMX2332 PLL chip,
very hard to read datasheet,
could not register on TI site to download their windows program,
so writing my own.

What could have been done in 10 lines in that datasheet,
is done over many pages with bit numbers in reverse,
starting bytes at bit 1, not 0,
and all sort of other strange things.
Maybe made by some intern or something,
maybe same person did their website..


It strongly reminded me of than bomb defusing manual
1) turn big screw 180 degrees left.
2) before you do that pull pin out of hole.
3)


Made some test cable for testing via PC par port,
and got some parts together to test and build that LMX2332
based board.
 http://panteltje.com/pub/par_port_test_cable_and_parts_LNB_PLL_IMG_6622.JPG
 
I like those cheap vero type boards with round isles,
fits exactly in alu housing too.
SMDs fit exactly between 2 isles.

I am writing code in C on the PC and test that chip,
then will rewrite it in PIC asm for the on-board PIC.
At least that is the plan.
If the C program works as I hope,
then I will release it open source so people are freed from that TI windows stuff.
Will be a command line tool though, its simple enough not to need any graphics.
if you can figure out that datasheet that is:
 http://panteltje.com/pub/LMX2332_registers.gif
  picture is copyright TI I think, from their datasheet...




 

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#518893

FromJohn Larkin <jjlarkin@highland_snip_technology.com>
Date2018-10-10 12:26 -0700
Message-ID<l7ksrdt7ur1k4br3hh1mdb864f81m8ovn9@4ax.com>
In reply to#518892
On Wed, 10 Oct 2018 19:12:10 GMT, <698839253X6D445TD@nospam.org>
wrote:

>John Larkin wrote
>>This is my hack for testing the dual-fet board:
>>
>>https://www.dropbox.com/s/fahyykwsjerh10y/Z440_C.JPG?raw=1
>>
>>This will work for the old single-fet version too.
>
>OK, that will give rise-time depending on circuit wiring - and scope lead capacitance I suppose.
>If you were to drive it with a ramp on one scope channel,
>it could give the pinch of point / transfer. 
>
>I don't know this transistor, suppose it is very fast,
>the chip on that mouse byte board only shows 'LXE'
>
>I have some Sirenza VCOs that use a similar mouse byte PCB,
>have not had any problems with that in prototyping
>
>Been coding a Linux test program for the LMX2332 PLL chip,
>very hard to read datasheet,
>could not register on TI site to download their windows program,
>so writing my own.

We had to develop c code to drive the LMX2571 synth chip. It has a 62
page data sheet and about 4000 registers, and involves all sorts of
rules and number-theory stuff. 

TI wasn't any help. They obviously have procedures to go from
frequency to register settings, and they obviously have c code in
their eval kits, and they refused to let us see any of that.






>
>What could have been done in 10 lines in that datasheet,
>is done over many pages with bit numbers in reverse,
>starting bytes at bit 1, not 0,
>and all sort of other strange things.
>Maybe made by some intern or something,
>maybe same person did their website..
>
>
>It strongly reminded me of than bomb defusing manual
>1) turn big screw 180 degrees left.
>2) before you do that pull pin out of hole.
>3)
>
>
>Made some test cable for testing via PC par port,
>and got some parts together to test and build that LMX2332
>based board.
> http://panteltje.com/pub/par_port_test_cable_and_parts_LNB_PLL_IMG_6622.JPG
> 
>I like those cheap vero type boards with round isles,
>fits exactly in alu housing too.
>SMDs fit exactly between 2 isles.
>
>I am writing code in C on the PC and test that chip,
>then will rewrite it in PIC asm for the on-board PIC.
>At least that is the plan.
>If the C program works as I hope,
>then I will release it open source so people are freed from that TI windows stuff.
>Will be a command line tool though, its simple enough not to need any graphics.
>if you can figure out that datasheet that is:
> http://panteltje.com/pub/LMX2332_registers.gif
>  picture is copyright TI I think, from their datasheet...
>
>
>
>
> 

-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

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

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#519075

From<698839253X6D445TD@nospam.org>
Date2018-10-12 17:57 +0000
Message-ID<ppqna4$q0c$1@gioia.aioe.org>
In reply to#518893
John Larkin wrote
>On Wed, 10 Oct 2018 19:12:10 GMT, <698839253X6D445TD@nospam.org>
>>Been coding a Linux test program for the LMX2332 PLL chip,
>>very hard to read datasheet,
>>could not register on TI site to download their windows program,
>>so writing my own.
>
>We had to develop c code to drive the LMX2571 synth chip. It has a 62
>page data sheet and about 4000 registers, and involves all sorts of
>rules and number-theory stuff. 
>
>TI wasn't any help. They obviously have procedures to go from
>frequency to register settings, and they obviously have c code in
>their eval kits, and they refused to let us see any of that.

I have the software framework running now, hard to find test vectors, 
but one thing bugs me in this chip:
there is one output pin that seems multiplexed to show different signals in the chip,
like outputs from different dividers etc...
But in the control registers you can set bits that connect more than one signal
at the same time to that pin.

So in theory it seems you can destroy the chip by sending the wrong config data.
That is very bad chip design IMO.

Maybe there is some protection, but then the datasheet is wrong.
So I added a software abort in case the wrong bits are set.

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#519083

FromJohn Larkin <jjlarkin@highland_snip_technology.com>
Date2018-10-12 12:55 -0700
Message-ID<vtu1sdp2439fdj9qhut00n6n5d2gded37l@4ax.com>
In reply to#519075
On Fri, 12 Oct 2018 17:57:09 GMT, <698839253X6D445TD@nospam.org>
wrote:

>John Larkin wrote
>>On Wed, 10 Oct 2018 19:12:10 GMT, <698839253X6D445TD@nospam.org>
>>>Been coding a Linux test program for the LMX2332 PLL chip,
>>>very hard to read datasheet,
>>>could not register on TI site to download their windows program,
>>>so writing my own.
>>
>>We had to develop c code to drive the LMX2571 synth chip. It has a 62
>>page data sheet and about 4000 registers, and involves all sorts of
>>rules and number-theory stuff. 
>>
>>TI wasn't any help. They obviously have procedures to go from
>>frequency to register settings, and they obviously have c code in
>>their eval kits, and they refused to let us see any of that.
>
>I have the software framework running now, hard to find test vectors, 
>but one thing bugs me in this chip:
>there is one output pin that seems multiplexed to show different signals in the chip,
>like outputs from different dividers etc...
>But in the control registers you can set bits that connect more than one signal
>at the same time to that pin.
>
>So in theory it seems you can destroy the chip by sending the wrong config data.
>That is very bad chip design IMO.
>
>Maybe there is some protection, but then the datasheet is wrong.
>So I added a software abort in case the wrong bits are set.

There have been some chips, like FPGAs, that could literally be fried
by software mis-configuration, but that's very rare. If the mux is
mis-programmed, it's unlikely that any damage would be done.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

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

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#519135

From<698839253X6D445TD@nospam.org>
Date2018-10-13 06:59 +0000
Message-ID<pps54m$ora$1@gioia.aioe.org>
In reply to#519083
John Larkin wrote
>>>On Wed, 10 Oct 2018 19:12:10 GMT, <698839253X6D445TD@nospam.org>
>>>>Been coding a Linux test program for the LMX2332 PLL chip,
>>>>very hard to read datasheet,
>>>>could not register on TI site to download their windows program,
>>>>so writing my own.
>>>
>>>We had to develop c code to drive the LMX2571 synth chip. It has a 62
>>>page data sheet and about 4000 registers, and involves all sorts of
>>>rules and number-theory stuff. 
>>>
>>>TI wasn't any help. They obviously have procedures to go from
>>>frequency to register settings, and they obviously have c code in
>>>their eval kits, and they refused to let us see any of that.
>>
>>I have the software framework running now, hard to find test vectors, 
>>but one thing bugs me in this chip:
>>there is one output pin that seems multiplexed to show different signals in the chip,
>>like outputs from different dividers etc...
>>But in the control registers you can set bits that connect more than one signal
>>at the same time to that pin.
>>
>>So in theory it seems you can destroy the chip by sending the wrong config data.
>>That is very bad chip design IMO.
>>
>>Maybe there is some protection, but then the datasheet is wrong.
>>So I added a software abort in case the wrong bits are set.
>
>There have been some chips, like FPGAs, that could literally be fried
>by software mis-configuration, but that's very rare. If the mux is
>mis-programmed, it's unlikely that any damage would be done.


Yes, the FPGA oscillating over a few gates really heats it up, causes hot spots!
Been there, done that, but it did survive.

In the LMX2332 datasheet I do not see any power on states of the configuration registers specified either.
Better have a current limiting resistor in the supply I think...

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#519164

FromJohn Larkin <jjlarkin@highlandtechnology.com>
Date2018-10-13 08:54 -0700
Message-ID<cm44sdhh6mao31nsdnl9ljihsranabt9qr@4ax.com>
In reply to#519135
On Sat, 13 Oct 2018 06:59:14 GMT, <698839253X6D445TD@nospam.org>
wrote:

>John Larkin wrote
>>>>On Wed, 10 Oct 2018 19:12:10 GMT, <698839253X6D445TD@nospam.org>
>>>>>Been coding a Linux test program for the LMX2332 PLL chip,
>>>>>very hard to read datasheet,
>>>>>could not register on TI site to download their windows program,
>>>>>so writing my own.
>>>>
>>>>We had to develop c code to drive the LMX2571 synth chip. It has a 62
>>>>page data sheet and about 4000 registers, and involves all sorts of
>>>>rules and number-theory stuff. 
>>>>
>>>>TI wasn't any help. They obviously have procedures to go from
>>>>frequency to register settings, and they obviously have c code in
>>>>their eval kits, and they refused to let us see any of that.
>>>
>>>I have the software framework running now, hard to find test vectors, 
>>>but one thing bugs me in this chip:
>>>there is one output pin that seems multiplexed to show different signals in the chip,
>>>like outputs from different dividers etc...
>>>But in the control registers you can set bits that connect more than one signal
>>>at the same time to that pin.
>>>
>>>So in theory it seems you can destroy the chip by sending the wrong config data.
>>>That is very bad chip design IMO.
>>>
>>>Maybe there is some protection, but then the datasheet is wrong.
>>>So I added a software abort in case the wrong bits are set.
>>
>>There have been some chips, like FPGAs, that could literally be fried
>>by software mis-configuration, but that's very rare. If the mux is
>>mis-programmed, it's unlikely that any damage would be done.
>
>
>Yes, the FPGA oscillating over a few gates really heats it up, causes hot spots!
>Been there, done that, but it did survive.

Xilinx had a generation of chips that used internal tri-state busses
for signal routing. You could do a design that turned on all the
tri-state buffers, some high and some low, and draw lots of amps. If
the power supplies held up, that would melt the chip.

They also had some that could be damaged if powerup dV/dT wasn't
right.

>
>In the LMX2332 datasheet I do not see any power on states of the configuration registers specified either.
>Better have a current limiting resistor in the supply I think...


Our LMX2571s are working beautifully. That functionality would have
been a rack full of gear, worth some good chunk of a magabuck, not
that long ago. The jitter levels are amazing. 

But the driver and the math were a real pain. We had to do the
repeated-fraction thing to get the optimum (N/M)/K  to best hit a
desired frequency. Brute force, it might be a week of computing.

TI should supply some sample code. I can't imagine why they don't. It
probably costs them sales.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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#519172

From<698839253X6D445TD@nospam.org>
Date2018-10-13 18:19 +0000
Message-ID<pptd0o$u8a$1@gioia.aioe.org>
In reply to#519164
John Larkin wrote
>Our LMX2571s are working beautifully. That functionality would have
>been a rack full of gear, worth some good chunk of a magabuck, not
>that long ago. The jitter levels are amazing. 
>
>But the driver and the math were a real pain. We had to do the
>repeated-fraction thing to get the optimum (N/M)/K  to best hit a
>desired frequency. Brute force, it might be a week of computing.


In my case it is not all that critical,
divide 10 MHz Rubidium by 10 to 1 MHz,
divide 24 MHz or 25 MHz VCXO by 24 or 25 to get 1 MHz,
compare those in phase detector, steer the 25 MHz or 24 MHz VCXOs.
Output 24 or 25 MHz with Rubidium stability.
The 24 MHz will be multiplied in the LNB by 390 to 9360 MHz, and used to mix down the 10.4 GHz satellite signal.
The 25 MHz will be multiplied by 390 or 426 for use as LO for normal satellite reception.
That is the plan anyways.
Nothing happened today, was working in the garden...


>TI should supply some sample code. I can't imagine why they don't. It
>probably costs them sales.

Too many possibilities I guess..
But indeed some examples do help.
Could use that to verify my program.

If all else fails I was sort of thinking I can use a PIC (build in counters).
I have a quite accurate PIC frequency counter in a D connector:
 http://panteltje.com/panteltje/pic/freq_pic/

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#518871

FromGeorge Herold <gherold@teachspin.com>
Date2018-10-10 06:40 -0700
Message-ID<38d16998-023d-48da-96e2-e96febbce5f8@googlegroups.com>
In reply to#518858
On Tuesday, October 9, 2018 at 11:23:06 PM UTC-4, John Larkin wrote:
> This has two of the tiny EPC BGA GaN fets and a gate driver. It can be
> used as a throw-away component on other boards.
> 
> https://www.dropbox.com/s/k5wvzrcwodk0scf/T852C.JPG?raw=1

Is that the same size as a 8-pin DIP?  That's a cute idea.

George H.
> 
> This is the dual-fet high-current version of the thing I posted a
> while back. The fets are in parallel but the drains come out to
> separate mouse-bites and test points so we can test everything
> properly.
> 
> Here's the test fixture.
> 
> https://www.dropbox.com/s/27ee1vspd4g9h1n/T852_Tester.JPG?raw=1
> 
> 
> -- 
> 
> John Larkin         Highland Technology, Inc
> 
> lunatic fringe electronics

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#518874

FromJohn Larkin <jjlarkin@highlandtechnology.com>
Date2018-10-10 07:38 -0700
Message-ID<lj3srdllevkuu2v3i3fbg5ni9vruq76ich@4ax.com>
In reply to#518871
On Wed, 10 Oct 2018 06:40:51 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

>On Tuesday, October 9, 2018 at 11:23:06 PM UTC-4, John Larkin wrote:
>> This has two of the tiny EPC BGA GaN fets and a gate driver. It can be
>> used as a throw-away component on other boards.
>> 
>> https://www.dropbox.com/s/k5wvzrcwodk0scf/T852C.JPG?raw=1
>
>Is that the same size as a 8-pin DIP?  That's a cute idea.

No, the size is pretty arbitrary. But it does surface-mount onto some
larger board. Those tiny fets will be glob-topped, and that makes
rework even more impossible, so we put the fets on a disposable
subassembly.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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