- Make use of existing components I had in stock. In this case, a bunch of 40Mhz PLE(Plextronics) DIP-8, 4pin oscillators.
- Do voltage conversion from whatever the OSC uses to whatever the mainboard expects/users.
- Keep the footprint small.
- Use this as a sort of re-usable module going forward.
| Part Count | Part Name | Package | Part | Usage | Notes |
|---|---|---|---|---|---|
| 1 | SN74LVC1T45 | SOT-23-6 | Single Channel Bidirectional Level Shifter | Takes the OSC clk_out and brings the voltage down to lower voltage. | 22 Ohm resistor has the DIR fixed so A goes to B only. |
| 2 | C23345 (LCSC Part Number) | 0603 SMD | 22 Ohm Resistor | Bridges signal pins to VCC | |
| 1 | PLE-SQ3300-40.00Mhz OSC | PDIP-8, 4pins, shortcan | 40Mhz 5V OSC | Plextronic's legacy/obsolete 40Mhz oscillator. | Generates a 5V, 40Mhz clock signal. Enable tied to VCC via resistor. Output goes to SN74LVC1T45 to have voltage reduced. |
| 1 | 1x4 header | 2.54mm 1x4 | Right angle male header 4 pins | Interface with parent module to provide a clock signal at the desired voltage levels. | Provides a "standard" way for me to add a clock source to another project board. Makes clock sources interchangable and/or re-usable. |
The assumption regarding the pinout of the OSC:
| Pin | Function |
|---|---|
| 1 | Enable/Disable (current limit resistor tied to 5V) |
| 4 | GND |
| 5 | Clock Output |
| 8 | VCC (5V) |
