SNAA390 Application note

Sinusoidal test is conducted at a fixed sinusoidal vibration frequency of 50, 100, 200, 500, 1000, and 2000 Hz with 10 g acceleration for all three axes. Phase noise plots from these tests are captured. The following plots are for the Z-axis for DLF-4 package. A spur sticking out at the frequency of vibration can be observed in each graph. Based on the test results and captured data, the vibration sensitivity in terms of ppb/g is calculated for BAW oscillators.

Figure 3-1 Baseline Capture Before Sinusoidal Vibration

Figure 3-2 Capture of Sinusoidal Vibration at 50 Hz

Figure 3-4 Capture of Sinusoidal Vibration at 200 Hz

Figure 3-6 Capture of Sinusoidal Vibration at 1000 Hz

Figure 3-3 Capture of Sinusoidal Vibration at 100 Hz

Figure 3-5 Capture of Sinusoidal Vibration at 500 Hz

Figure 3-7 Capture of Sinusoidal Vibration at 2000 Hz

The combined, overlaid waveform for the phase noise plots with respect to vibration frequencies are shown in the following figures. The figures show waveforms for the DLE-4, DLF-4, DLE-6, and DLF-6 packages.

The ppb/g is calculated and plotted for both LVCMOS and LVPECL. Each of the following figures show Z-axis data with the device at 10 g acceleration.

Figure 3-8 Combined Sinusoidal Vibration Phase Noise Plot on 4-pin DLE Package

Figure 3-10 Combined Sinusoidal Vibration Phase Noise Plot on 6-pin DLE Package

Figure 3-9 Combined Sinusoidal Vibration Phase Noise Plot on 4-pin DLF Package

Figure 3-11 Combined Sinusoidal Vibration Phase Noise Plot on 6-pin DLF Package

The calculated ppb/g values for the LMK6x on LVCMOS and LVPECL devices for both the DLE and DLF packages are plotted for all the tested vibration frequencies. These calculations are based on the vibration frequency spurs in phase noise measurements for various vibration frequencies for different types of LMK6x packages and output types. The equations are provided in Section 3.1.1. Figure 3-12 shows the vibration frequency versus the ppb/g value. The vibration sensitivity of the LMK6x LVCMOS output type is less than 1 ppb/g and the vibration sensitivity for the LMK6x differential output is less than 2 ppb/g based on the plots. In Figure 3-12, the top plot is the X-axis, the middle plot is the Y-axis, and the bottom plot is the Z-axis ppb/g versus the vibration frequency. The blue line in Figure 3-12 represents the DLE package and the green line represents the DLF package. The vibration sensitivity of the crystal oscillators are in the range of 10 ppb/g, which shows that the BAW oscillators have less vibration sensitivity compared to crystal oscillators.

Figure 3-12 ppb/g Versus Vibration Frequency Plot for LVCMOS Output - DLE and DLF packages - X, Y, Z Axis

Figure 3-13 ppb/g Versus Vibration Frequency Plot for Differential Output - DLE and DLF Packages - X, Y, Z Axis

3.1.2 Results From Sinusoidal Vibration Test