UG123: SiOCXO1-EVB Evaluation Board User's Guide The Silicon Labs SiOCXO1-EVB (kit) is used to help evaluate Silicon Labs Precision Jitter Attenuation/Frequency Translation product line for Stratum 3/3E, IEEE 1588 and G.8262 SyncE applications. EVB FEATURES: • Flexible Output Termination • Power Supply Filtering • Optional Output Buffer • Optional OCXO Voltage Control Adjust silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 UG123: SiOCXO1-EVB Evaluation Board User's Guide Quick Start 1. Quick Start Refer to Figure 3.1 Functional Block Diagram on page 3, Figure 3.2 SiOCXO1-EB Shown Populated with an OCXO on page 3, and Figure 4.1 SiOCXO1-EB Configured with Si5348 EVB on page 5 to clarify the instructions below. 1. Connect power to J1, and note that start-up current could be on the order of 1 amp. Check the manufacturers warm-up time. 2. Connect SiOCXO1-EB output, J2, to the Si5348 REF clock input using the short SMA cable provided with the EVB kit. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 1 UG123: SiOCXO1-EVB Evaluation Board User's Guide Top Layer View of Board 2. Top Layer View of Board Figure 2.1. Top Layer View of Board silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 2 UG123: SiOCXO1-EVB Evaluation Board User's Guide Functional Description 3. Functional Description The SiOCXO1-EB is used in conjunction with Silicon Labs precision timing devices to facilitate characterization. The SiOCXO1-EB was designed to maximize output termination configurations as well as optional control voltage terminations. Resistors and capacitors are 0603, which makes it simple to remove and add various values. The SiOCXO1-EB bill of materials and PCB layouts are in Section 7. Bill of Materials and Section 6. Schematic. The block diagram for the board is provided below: Figure 3.1. Functional Block Diagram The SiOCXO1-EB is intended to be a general use board for a 7-pin OCXO with 22x25 nominal package size, such as the Rakon P/N STP3158 12.8 MHz pictured below. See Section 6. Schematic for example measurements carried out using this OCXO. Figure 3.2. SiOCXO1-EB Shown Populated with an OCXO 3.1 Power Supply The power supply voltage and current requirements are listed in the manufacturers data sheet. A 3.3 V ±5% supply is required. R6 may require modification if other voltages are used. Also, note the OCXO initial current can be on the order of 1A. Power supply filtering has been added to the evaluation board to minimize spurious response. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 3 UG123: SiOCXO1-EVB Evaluation Board User's Guide Functional Description 3.2 Output Termination and Optional Buffer In most applications simple R C termination is used, as seen with R1 and C4 in Figure 6.1 SiOCXO1-EB Schematic on page 7. This is a resistor to optimize impedance matching and a capacitor to block DC. Modifications can be made as required. Optionally a buffer can be added to minimize loading on the OCXO’s output, such as when driving cables. In this case U2, J6, C7, C8, R8, and R9 must be populated, while R2 can be depopulated. 3.3 Optional OCXO Frequency Adjust Some OCXO’s have an optional control voltage to adjust the output frequency, usually by a small amount such as 1 or 2 ppm. One example would be to discipline the OCXO to reduce the effects of OCXO aging. In this case, J3 and R4 must be populated as a minimum. C6 can be used for filtering or BW frequency limiting. Alternatively, R5 and C6 could be fixed or adjustable resistors to set a DC bias voltage. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 4 UG123: SiOCXO1-EVB Evaluation Board User's Guide Configuring the SiOCXO-EB 4. Configuring the SiOCXO-EB Figure 4.1. SiOCXO1-EB Configured with Si5348 EVB The connection between the SiOCXO-EB and Si5348 EVB should be kept as short as possible. It is recommended to use a UPS Power Supply back-up for long term testing. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 5 UG123: SiOCXO1-EVB Evaluation Board User's Guide SiOCOXO1-EB Functionality Test 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. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 6 UG123: SiOCXO1-EVB Evaluation Board User's Guide Schematic 6. Schematic Figure 6.1. SiOCXO1-EB Schematic silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 7 UG123: SiOCXO1-EVB Evaluation Board User's Guide Bill of Materials 7. Bill of Materials Table 7.1. SiOCXO1-EB Bill of Materials BOM Digikey Footprint Item Quantity Reference Part Manufacturer Manufacturer Part Number 1 1 C1 10UF_805 Venkel C0805Y 5V6R31 06ZN 805 2 2 C2,C8 100N Venkel C0402X 7R6R3104KNE 402 3 1 C3 10NF Venkel LIC0204 X6S6R3 -103MN E 204 4 2 C4,C5 100N Venkel C0603X 7R160-1 04KNE 603 7 1 D1 Red Panasonic LN1271 RAL 8 5 9 1 J1 Phoenix_2_scre w Phoenix MKDSN 1.5/2-5.0 8 277-1247-ND Phoenix2pinM_p2pit ch 10 1 J2 SMA_ED GE Johnson 142-070 1-801 J502-ND SMA_EDGE_p 062 12 2 J4,J5 Jmpr_1pin 13 1 L1 Ferrite Steward HI1612X 560R-10 1612 14 1 R1 37.4 Venkel CR0603 -16W-37 R4FT 603 15 1 R2 0 ohm Venkel CR0603 -16W-00 0T 603 18 1 R6 150 Venkel CR0603 -16W-15 00FT 603 21 1 U1 12.8 MHz Rakon STP315 8 5 1 C6 1UF Venkel C0603X 7R6R3105KNE P493CT-ND H1,H2,H3,H HOLE_NU 4,H5 M4 silabs.com | Smart. Connected. Energy-friendly. Comment LED_gull_flip platedNum4hole 1pin_p1pitch Alternate = Connor Winfield OH300-50503CF-0 12.8M or AVX OO12.8000000M1 4070AT NOPOP 603 Rev. 1.0 | 8 UG123: SiOCXO1-EVB Evaluation Board User's Guide Bill of Materials Item Quantity Reference Part Manufacturer Manufacturer Part Number BOM Digikey Footprint 6 1 C7 100N Venkel C0603X 7R160-1 04KNE NOPOP 11 2 J3,J6 SMA_ED GE Johnson 142-070 1-801 NOPOP 16 2 R3,R7 49.9 Venkel CR0603 -16W-49 R9FT NOPOP 603 17 2 R4,R5 1K Venkel CR0603 -16W-10 01FT NOPOP 603 19 2 R8,R10 0 ohm Venkel CR0603 -16W-00 0T NOPOP 603 20 1 R9 37.4 Venkel CR0603 -16W-37 R4FT NOPOP 603 22 1 U2 NC7SV34 Fairchild NC7SV3 4P5X NOPOP Comment 603 J502-ND NC7SV34P5XND SMA_EDGE_p 062 SC-70-5 Alternate = Fairchild NC7SZ126M5X Note: The OCXO must be populated if it is not. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 9 UG123: SiOCXO1-EVB Evaluation Board User's Guide Layout 8. Layout Figure 8.1. Layer 1: Primary Side Figure 8.2. Layer 2: Ground silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 10 UG123: SiOCXO1-EVB Evaluation Board User's Guide Layout Figure 8.3. Layer 3: Power Figure 8.4. Layer 4: Secondary Side silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 11 ClockBuilder Pro One-click access to Timing tools, documentation, software, source code libraries & more. Available for Windows and iOS (CBGo only). www.silabs.com/CBPro Timing Portfolio www.silabs.com/timing SW/HW www.silabs.com/CBPro Quality www.silabs.com/quality Support and Community community.silabs.com Disclaimer Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using or intending to use the Silicon Laboratories products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific device, and "Typical" parameters provided can and do vary in different applications. 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