[time-nuts] Slightly OT: interest in a four-output, ultra-low jitter, synthesizer block?

Gerhard Hoffmann dk4xp at arcor.de
Sat Jan 27 09:30:12 EST 2018

Am 25.01.2018 um 15:32 schrieb John Ackermann N8UR:
> The challenge is that the chip is a 7x7 mm 44-QFN package and really 
> wants to be put on a six-layer circuit board.  That's doable, but 
> challenging, for home assembly.
> Rather than designing the chip into a larger circuit board, I'm 
> thinking of doing a small "carrier" board that would include just the 
> chip and critical bypass caps and have headers to plug into the main 
> board. Then, you could just drop the carrier into a project-specific 
> board and not have to worry about the complex layout and mounting.  I 
> have a contract manufacturer who can build these up, if there's enough 
> quantity to justify the setup cost.


would this here be an acceptable solution?

No need for 6 layers.

Fanout of the chip to 100 mil wire wrap pins,
lives on 3.6 to 5V,
has regulators for the voltages needed:

LT3080   1V8 for digital core
LT3042   3V3 for analog core
LT3042   1V8 or 2V5 or 3V3 for IO voltage

Voltage for outputs can be selected per port between 1V8 core and IO 
with a jumper wire.

There is a crystal and a CTS SMD oscillator.

Clock input 0:    just 1:1
Clock input 1:    differential with termination for PECL / LVDS
Clock input 2:    onboard oscillator
Clock input 3:    onboard crystal

Board size is abt. 1*2 inches, design rules 8mil/8mil, 1 signal layer + 
1 GND layer.
You can cut away the left half if you definitely want only the fanout.

Via sizes are harmless enough for my DIY etch process, 0603 parts.

Altium Designer files are available, or Gerbers after review.
All parts available @ DigiKey.

I don't intend to push that much further :-)

73, Gerhard DK4XP

I hope the 2 .pngs are okay by size.

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