Are you looking for a quick and simple way to test a crystal oscillator? IQD Frequency Products has developed a new board to do just that. With the IOSC-EV Board there is no need to worry about designing and building your own test circuit. The board can be used to test standard surface mount clock oscillators, VCXOs or TCXO/VCTCXOs.
The IOSC-EV Board comes with six smaller boards that can be snapped from the side of the main board and onto which different size 4 pad packaged oscillators can be soldered. The smaller board can then be soldered to the main PCB. The six different package sizes are 1.6 x 1.2mm, 2.0 x 1.6mm, 2.5 x 2.0mm, 3.2 x 2.5mm, 5.0 x 3.2mm & 7.0 x 5.0mm.
Because power supply noise can affect the frequency of the oscillator, the IOSC-EV Board includes a regulated and filtered power supply which can be set to anywhere between 1.8V and 5.0V. This allows seeing the best performance from the oscillator under ideal situations. However during testing one may want to inject noise on the power rail and monitor the effect, so the IOSC-Board also includes the option to apply power directly to the PCB.
The Enable/Disable function can be tested by means of a manual switch to observe the effect on the current draw, and there is also the ability to drive this input high or low from a digital source should you want to measure the enable time. For products with a Voltage Control Input, such as a VCXO or VCTCXO there is a potentiometer on the PCB to allow trimming out the frequency tolerance and the effect of the soldering, to bring the frequency to nominal.
It can be also used to manually adjust the voltage control input and measure the effect on the frequency. For sensitive products such as VCTCXOs there is an option to trim out the tolerance, measure the potentiometer resistance, then replace with fixed resistors for reduced noise, thus achieving best stability, jitter, and phase noise. Of course the voltage control input can also be adjusted from an external analogue source.
On the output stage the IOSC-EV Board offers three load configurations. CMOS output can be terminated into a 15pF load, then buffered to give a 50ohms output impedance that can be connected directly to test equipment such as frequency counters. Clipped sine wave output can be terminated into 10kohms 10pF load, then buffered to give a 50ohm output impedance that can be terminated directly into test equipment. The oscillator output can also be accessed directly, without any buffers or load, this can be useful for certain test setups, but caution is advised as incorrect setup may adversely affect the oscillator. All these outputs are terminated in an SMA connector.
The Eval Board is available in two options. The first is a non-populated PCB which is supplied with the bill of materials required to operate the test circuit and the second option is a populated board ready to be used. The non-populated version will be available free of charge to the first 400 visitors at the IQD stand at electronica 2018.
