The IOSC evaluation board comes with six smaller boards, which can be broken off from the main board. 4-pad oscillators of different sizes (1.6×1.2mm, 2.0×1.6mm, 2.5×2.0mm, 3.2×2.5mm, 5.0×3.2mm and 7.0×5.0mm) can be mounted on these smaller boards. The substrates for the oscillators are then soldered onto the large board. As disturbances to the supply voltage can influence the frequency of the oscillator, the IOSC evaluation board contains a regulated and attenuated supply voltage that can be freely selected between 1.8 and 5.0 V. This way the performance of the oscillator can be observed under ideal conditions. The Evaluation Board offers the option of connecting the supply voltage directly on the board, such that disturbances and noise can be introduced in test phases and their implications understood.
The enable/disable function can be manually tested in order to precisely observe the effect and the current drawn. For products with pulling input, such as VCXOs or VCTCXOs, a potentiometer is mounted on the board to reduce the frequency tolerance and the effect of soldering and to bring the frequency back to the nominal value. In addition, the pulling input can be used for manual testing the effects on the frequency. For sensitive products like VCTCXOs, it is possible to improve stability, jitter and phase noise. Firstly, the tolerance is brought to the normal value with the aid of the pulling voltage. Then the resistance of the potentiometer has to be measured and replaced by a fixed resistor.
The IOSC evaluation board offers three connection configurations at the output stage. One can choose between a CMOS output, a clipped sine wave output or a direct output without buffer or load. All outputs have an SMA connector.
Würth Elektronik – www.we-online.com