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Multi Frequency Oscillator

author: skum
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2 layer board of 0.92 x 0.61 inches (23.4 x 15.4 mm)
Uploaded: August 13th 2018
Shared: September 16th 2018
Total Price: $2.75

**A revision B that is physically smaller, but functionally identical [here](https://www.oshpark.com/shared_projects/…

A revision B that is physically smaller, but functionally identical here

Idea taken from https://nfggames.com/forum2/index.php?topic=5744.0 but since I sometimes needed to switch two frequencies, I made this. Example where it is usable, is when a PSX switches between NTSC and PAL, it needs to switch both the carrier frequency of the video signal AND the clock frequency to the DAC to have a proper video signal that doesn’t go black and white and so on.

Parts list:

  • U1 1.8V LDO Regulator, here a TPS78218 (Mouser P/N: 595-TPS78218DDCT)
  • U2 Texas Instruments CDCE925 (Mouser P/N: 595-CDCE925PWR)
  • C1 1uF 0603 SMD capacitor
  • C2 1uF 0603 SMD capacitor
  • C3 1uF 0603 SMD capacitor
  • C4 1uF 0603 SMD capacitor
  • R1 10K 0603 SMD resistor
  • R2 10K 0603 SMD resistor
  • R3 18R 0603 SMD resistor (or whatever needed to accomodate signal to the circuit)
  • R4 18R 0603 SMD resistor (or whatever needed to accomodate signal to the circuit)
  • Y1 27MHz crystal ((Mouser P/N: 774-ATS270BSM-1E or the shallower 815-ABLS3-27MD4YFT)

Use 0.8mm substrate for a shallow profile.

Note that Y2 and Y4 are parallel coupled, same with Y3 and Y5. Thus if programming with TI’s ClockPro software, Y4 must be tri-stated when Y2 output is on, and Y5 should be tri-stated when Y3 is on. Of course also vice-versa.

More info here

**A revision B that is physically smaller, but functionally identical [here](https://www.oshpark.com/shared_projects/…

A revision B that is physically smaller, but functionally identical here

Idea taken from https://nfggames.com/forum2/index.php?topic=5744.0 but since I sometimes needed to switch two frequencies, I made this. Example where it is usable, is when a PSX switches between NTSC and PAL, it needs to switch both the carrier frequency of the video signal AND the clock frequency to the DAC to have a proper video signal that doesn’t go black and white and so on.

Parts list:

  • U1 1.8V LDO Regulator, here a TPS78218 (Mouser P/N: 595-TPS78218DDCT)
  • U2 Texas Instruments CDCE925 (Mouser P/N: 595-CDCE925PWR)
  • C1 1uF 0603 SMD capacitor
  • C2 1uF 0603 SMD capacitor
  • C3 1uF 0603 SMD capacitor
  • C4 1uF 0603 SMD capacitor
  • R1 10K 0603 SMD resistor
  • R2 10K 0603 SMD resistor
  • R3 18R 0603 SMD resistor (or whatever needed to accomodate signal to the circuit)
  • R4 18R 0603 SMD resistor (or whatever needed to accomodate signal to the circuit)
  • Y1 27MHz crystal ((Mouser P/N: 774-ATS270BSM-1E or the shallower 815-ABLS3-27MD4YFT)

Use 0.8mm substrate for a shallow profile.

Note that Y2 and Y4 are parallel coupled, same with Y3 and Y5. Thus if programming with TI’s ClockPro software, Y4 must be tri-stated when Y2 output is on, and Y5 should be tri-stated when Y3 is on. Of course also vice-versa.

More info here

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      Hey there! Before ordering, make sure you have all all the info you need to complete and use this design. This usually means a component list, and sometimes additional information such as assembly notes, source code, or usage guides.
      Since this is a project designed by a community member, it may contain design errors that prevent it from working as intended. OSH Park cannot place any guarantees about the functionality or correctness of the design.
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