Fast and precise testing of standard oscillators VCXOs and TCXO/VCTCXOs

08-11-2021 | IQD | Design & Manufacture

Being able to test oscillators easily and quickly is more than attainable utilising the IOSC EVBoard. The evaluation board is ideal for measuring most surface mount standard oscillators, VCXOs or TCXO/VCTCXOs. It is available now from IQD, part of the Würth Elektronik eiSos Group.

The board is supplied with six smaller boards that can be snapped off the mainboard and onto which different sized four-pad oscillators can be soldered. The smaller board may then be soldered to the mainboard. The six different package sizes are 1.6mm x 1.2mm, 2mm x 1.6mm, 2.5mm x 2mm, 3.2mm x 2.5mm, 5mm x 3.2mm and 7mm x 5mm.

Since noise in the supply voltage may affect the frequency of the oscillator, the board contains a filtered and regulated supply voltage. It can be freely selected between 1.8V and 5V. This enables the performance of the oscillator to be considered under perfect conditions. However, it may also be required to intentionally introduce noise through testing to observe the consequences. For this purpose, the board also provides the option to connect a supply voltage directly.

The Enable/Disable function may be tested by manual switching to scrutinise the effect on current draw. Also, there is the possibility to set this input to 'high' or 'low' through a digital source to measure the enable time. For products with voltage control input, including VCXOs and VCTCXOs, the board comprises a potentiometer to bring the frequency tolerance and the effect of soldering back to the nominal frequency by pulling. This process may further be employed to manually adjust the control voltage to simulate the effect on frequency. For sensitive products such as VCTCXOs, as well as pulling the frequency, there is the possibility to substitute the applied potentiometer resistor by a fixed resistor. This leads to greater stability and optimised jitter as well as phase noise.

For the output signal the board provides three configurations. Here users can select between a CMOS output, a clipped sine or a direct output without buffer or load. All outputs are terminated in an SMA connector.

The evaluation board is offered in two options – as an unpopulated PCB supplied with the appropriate BOM and as a populated board for immediate use. The unpopulated version is currently offered free of charge from the company with the next 200 oscillator sample orders.

By Natasha Shek