Clock In A Can

Customizable can and half-can style crystal oscillators

Have you noticed that it is getting harder and harder to find through-hole oscillators in the metal can or half-can packages? The selection has been shrinking as manufacturers discontinue entire legacy product lines.

Fortunately, there is a solution! The ClockInACan is a small circuit board that is the same size as the oscillator and duplicates the same function exactly. Just provide your own crystal of the desired frequency or a multiple of the desired frequency, and set the three solder jumpers to select the divide ratio.

Features include

• Wide +2V to +5.5V power supply range
• Logic-level enable pin with internal pullup
• CMOS-compatible output
• Selectable divide ratio of 1, 1/2, 1/4, 1/8, 1/16, and 1/32
• Crystal footprint fits through hole and many surface mount crystals
• Pins are breadboard compatible, and also fit in DIP sockets
• Pins have labels underneath the PCB for your convenience

Here is the schematic.

Fab files can be found here:

• ClockInACan fab files
• ClockInAHalfCan fab files

The basic bill of materials is below.

Q	Designator	Description	Mouser Part Number
1	U1	Oscillator IC	513-NJU6311RB2-TE1
1	C1	0.1uF capacitor	603-CC603KRX7R9BB104
0	C2, C3	Optional load caps
0	R1, R2, R3	Divider jumpers
1	R4	0 ohm solder jumper
1	Y1	Crystal
4	J1, J7, J8, J14	PCB pins	575-0542000150000

Board dimensions below. Order the board in whatever cool colors you like!

• ClockInACan: 0.8 x 0.5 inches
• ClockInAHalfCan: 0.5 x 0.5 inches

Assembly Notes

I've found it easiest to install the pins before soldering any components on the board. Make a jig out of a block of wood, like this:

Then put the ClockInACan board on top, drop the four pins in place, and place the whole thing into a small press or a bench vise, like this:

Apply enough pressure to push the pins into place, but no more.

Solder in C1 first, then U1 and R4. Set the R1, R2, and R3 jumpers to your desired oscillator divider setting as follows:

R1	R2	R3	Setting
Open	Open	Open	1
Short	Open	Open	/2
Open	Short	Open	/4
Short	Short	Open	/8
Open	Open	Short	/16
Short	Open	Short	/32

For your convenience, this table is reproduced on the bottom of the ClockInACan PCB (although the ClockInAHalfCan does not have it due to space constraints).

Install Y1, taking care not to short any component leads on the metal case of the crystal. You may want to add Kapton tape to insulate the board from the crystal. Large HC49 crystals can be folded over to save vertical space.

Advanced Topics

The NJU6311 includes built-in load caps so C2 and C3 are not necessary unless you have a particularly picky crystal. Similarly, R4 can be 0 ohms, but with some crystals you may need to increase the resistance to reduce the drive current. For further information see the NJU6311 datasheet.

License

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. See https://creativecommons.org/licenses/by-sa/4.0/.