Oven Controlled Crystal Oscillator Kit


Oven Controlled Crystal Oscillator OCXO

SKU: OCXO Category: Tag:


<span>This kit is an Oven Controlled Crystal Oscillator (OCXO) version of the </span><a href="https://www.qrp-labs.com/synth" target="_blank">standard Si5351A Synthesiser module kit</a><span><span>. The 27MHz OCXO is kit-built, it does not use an expensive commercial OCXO component. Construction of this kit is more difficult than the other kits, however it does not require any special techniques or equipment, as long as the construction steps are followed carefully.<br /><br /></span></span><p>The Si5351A is a relatively recent clock-generator chip manufactured by <a href="http://www.silabs.com/" target="_blank">SiLabs</a>. It can produce three simultaneous independent 50-ohm impedance, squarewave outputs between 8kHz and 200MHz. Configuration of the chip is via a microcontroller with I2C (two-wire) interface.</p><p><span><strong>NOTE</strong></span>: QRP Labs tested the actual frequency range of the Si5351A outputs. The minimum frequency configuration with 27MHz crystal produces 3.515kHz output. The maximum frequency appears to be an internal limitation (not limited by the configuration) and was approximately 292MHz. Of course, outside the specified range of the datasheet, there are no guarantees…</p><p>The 27MHz OCXO is a kit-built oven made of PCB pieces. The Supplied PCB measuring 10 x 8cm breaks into 16 pieces: one main PCB and 15 small pieces which make up three boxes, that are used for the oven chamber and external box. The Proportional Integral temperature controller is simple but effective.</p><p>This OCXO/Si5351A synthesiser module kit requires a 5V supply. The tiny 0.5mm pin-spaced<strong> Si5351A chip is pre-soldered to the PCB</strong> at the factory. The remaining components are all through-hole components. The component density is quite high and construction requires following the instruction manual steps carefully. The circuit contains two 3.3V regulator and I2C level converters, for use with the I2C bus in 5V microcontroller systems. The kit has a 2 x 10-pin 0.1-inch header for all connections.</p><p>The synthesizer may be used in a variety of projects. The pinout has been designed to be somewhat similar to the popular AD9850 DDS module and may be substituted in certain cases (with appropriate software changes in the controller). This Si5351A module is also designed to be compatible with the <a href="https://www.qrp-labs.com/ultimate3" target="_blank">Ultimate3/Ultimate3S QRSS/WSPR kits</a>. It can be plugged into the <a href="https://www.qrp-labs.com/ultimate3" target="_blank">U3 kit</a> with certain minimal hardware modifications to the U3. It is directly compatible with the <a href="https://www.qrp-labs.com/ultimate3/u3s.html" target="_blank">Ultimate 3S kit</a> without modification. It requires Ultimate3 firmware v3.07 or above, to communicate with the Si5351A via I2C. Note that for use in the original U3 kit, not U3S, (PCB revisions 1 to 4), pin 12 of the header needs to be removed before installation.</p>