5. SiOCOXO1-EB Functionality Test
1. Connect power to J1 (3.3 V).
2. Connect SiOCXO1-EB Output, J2, to an oscilloscope (terminate into 50 Ω).
3. Verify that the red LED is illuminated, the current draw matches closely to the specs, and the output matches the OCXO’s data
sheet.
5.1 Example Measurement Results Using STP3158LF 12.8 MHz OCXO from Rakon
Table 5.1. Current Specs for Rakon P/N STP3158 12.8 MHz at U1
Example Current Draw
Expected Value (Data Sheet)
Example Measured Value
Warm-up
≤ 0.9 A
0.72 A
Steady State
≤ 0.3 A
0.29 A
Notes on Current Settling:
1. The system (including the LED and OCXO) initially drew 0.72–0.74 A of current from the 3.3 V power supply. At one minute,
the current draw slightly decreased by 0.02–0.04A (warm-up time). Around the minute mark the current decreased rapidly to
0.32–0.37A. Then, the system decreased slightly to its consistent steady state current of 0.30 A within 20 minutes.
2. The LED draws around 10 mA, so subtract this from the power supply (system) current to get the current draw of the OCXO alone.
These are the values reflected in the table above.
Steady State Output Waveform for Rakon P/N STP3158 12.8 MHz at U1
Verify the output is a 12.8 MHz LVCMOS waveform. For example, measure with a Tektronix TDS 20245, 200 MHz oscilloscope
terminated with 50 Ω BNC T connector.
UG123: SiOCXO1-EVB Evaluation Board User's Guide • SiOCOXO1-EB Functionality Test
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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Rev. 1.1 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • July 26, 2021
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