Texas Instruments LMX2492 User Manual Download Page 17 | Manualshive

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Texas Instruments LMX2492 User Manual Download Page 17

PLL Phase Noise

Figure 6-2. Phase Noise with a Wide Loop Bandwidth

The figure above shows phase noise with a wide loop bandwidth and 100 MHz phase detector frequency.
At about 260 kHz, the phase noise is -113.1 dBc/Hz, which is actually being degraded by 0.5 dB by the 1/f
noise. This implies a figure of merit of -227.2 dBc/Hz.

17

SNAU160C – March 2014 – Revised November 2014

Typical Performance Measurements

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Copyright © 2014, Texas Instruments Incorporated

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Summary of Contents for LMX2492

Page 1: ...LMX2492 Evaluation Instructions Ultra Low Noise Frequency Synthesizer with Integrated VCO Evaluation Board Operating Instructions User s Guide Literature Number SNAU160C March 2014 Revised November 2014 ...

Page 2: ...ngs 6 2 2 1 Port Setup 6 2 2 2 Device Selection 7 2 2 3 Bits Pins Tab and Restoring the Default Configuration 8 2 2 4 Registers Tab 9 2 2 5 PLL Frequency Tab 10 2 2 6 Ramp Generator Tab 11 3 Schematic 12 4 Board Layers Stackup 13 5 Bill of Materials 14 6 Typical Performance Measurements 16 6 1 PLL Phase Noise 16 6 2 Ramping Example 19 Revision History 20 2 Contents SNAU160C March 2014 Revised Nove...

Page 3: ...h 2014 Revised November 2014 Evaluation Board Operating Instructions 3 SNAU160C March 2014 Revised November 2014 Evaluation Board Operating Instructions Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated ...

Page 4: ...ult but can be configured if necessary 1 1 2 VCC 5V The board operates on 5V and regulates this down to 3 3 V for the PLL The board can be configured to operate wit separate 1 1 3 VCC 3P3V This is actually supplied from the regular off the 5V supply but can also be run from a 3 3 V supply if the regulator is disconnected and a few resistors are changed 1 1 4 USB2ANY Connector Connect the board to ...

Page 5: ...CO Frequency 9 4 10 1 GHz VCO Gain MHz V 200 MHz V C1_LF 68 pF C2_LF 3 9 nF C3_LF 150 pF C4_LF Open R2 390 Ω R3_LF 150 Ω R4_LF 0 Ω Charge Pump Gain 3 1 mA Phase Detector Frequency 100 MHz OSCin Frequency 100 MHz 5 SNAU160C March 2014 Revised November 2014 Evaluation Board Configuration Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated ...

Page 6: ...oard it is recommended to click the Identify button and ensure the LED light is blinking to ensure that this is working correctly Note that position 3 is MUXout which can be used for readback In order to do this the MUXout pin needs to be programmed to Readback and also resistor R68 needs to be placed Figure 2 1 LMX2492 Port Setup 6 Evaluation Board Configuration SNAU160C March 2014 Revised Novemb...

Page 7: ...2 2 2 Device Selection Go to Select Device PLL Fractional LMX2492 Figure 2 2 Part Selection 7 SNAU160C March 2014 Revised November 2014 Evaluation Board Configuration Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated ...

Page 8: ...ar at the bottom One can right mouse click on any field for a short description of what it does To restore the part to the original software configuration on can select the default mode as shown Figure 2 3 Restoring Default Mode 8 Evaluation Board Configuration SNAU160C March 2014 Revised November 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated ...

Page 9: ...stor R68 to connect this pin back to the programming header Once this is done entire registers can be read or a specific field can be typed in to read the value Realize that some fields of the LMX2492 are read only and therefore might not be the same as written to Figure 2 4 Registers Tab 9 SNAU160C March 2014 Revised November 2014 Evaluation Board Configuration Submit Documentation Feedback Copyr...

Page 10: ...2 2 5 PLL Frequency Tab Verify your PLL Tab looks like below Figure 2 5 PLL Frequency Tab 10 Evaluation Board Configuration SNAU160C March 2014 Revised November 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated ...

Page 11: ...e 2 6 Enabling the Flex Scripts for the Ramp Generator GUI Then Click on Update All and wait until you see your screen populate to below Notes for Ramp Calculator tab Manually change the OSCin Frequency in the Ramp Calculator tab when you change the value in the PLL tab Click Update All whenever you change values in the frequency section Only modify values in Yellow regions Click and unclick RST t...

Page 12: ...4 Schematic Refer to Chapter 5 for actual component values Also realize that not all components are placed on this board 12 Schematic SNAU160C March 2014 Revised November 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated ...

Page 13: ...board shall include Blue is dielectrics Top layer for high priority high frequency signals GTL 1 oz CU RO4003 Dielectric 16 mils Ground plane GP1 FR4 18 mils thick Power plane VccCLK GP2 FR4 22 mils Bottom layer copper clad for thermal relief GBL Table 4 1 Top to Bottom Layer Order LMX2492 GTL 1 Top Layer LMX2492 GP1 2 GND Plane LMX2492 G1 3 Power LMX2492 GBL 4 Bottom Layer Figure 4 1 Board Layers...

Page 14: ...m 12 Y MuRata BLM18SG121TN1D 8 L5p L6 L7 L8 100MHz SMD OSCin RFout Connector SMT End launch 13 Y Emerson 142 0701 851 4 RFout 2 Vcc_5V SMA 50 ohm RES 51 ohm 5 0 063W 14 R1 Y Vishay Dale CRCW040251R0JNED 1 0402 RES 18 ohm 5 0 063W 15 R2 R6 R7 Y Vishay Dale CRCW040218R0JNED 3 0402 16 R2_LF RES 390 ohm 5 0 1W 0603 Y Vishay Dale CRCW0603390RJNEA 1 RES 68 ohm 5 0 063W 17 R3 Y Vishay Dale CRCW040268R0JN...

Page 15: ...tional N PLL with 28 U1 Y Texas Instruments LMX2492QRTW 1 Ramp Chirp Generation RTW0024A 29 U2 VCO 9 8 11 3GHz SMD Y RF Micro Devices RFVC1843 1 Ultra Low Noise 150mA Linear Regulator for RF Analog Circuits 30 U6 N Texas Instruments LP5900SD 3 3 1 Requires No Bypass Capacitor 6 pin LLP 31 uWire Connector FCI 52601 G10 8LF 1 OSC 100 0000MHZ 3 3V 32 Y2 Y Connor Winfield CWX813 100 0M 1 25PPM SMD 15 ...

Page 16: ... Phase Noise in Default Mode The above figure shows the phase noise in default for mode Note that this is the VCO frequency as it was observed on the Fout 2 output 16 Typical Performance Measurements SNAU160C March 2014 Revised November 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated ...

Page 17: ... 100 MHz phase detector frequency At about 260 kHz the phase noise is 113 1 dBc Hz which is actually being degraded by 0 5 dB by the 1 f noise This implies a figure of merit of 227 2 dBc Hz 17 SNAU160C March 2014 Revised November 2014 Typical Performance Measurements Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated ...

Page 18: ...Tuning Voltage The phase noise of the LMX2492 does vary somewhat with tuning voltage with the best performance typically near lower tuning voltages Table 6 1 Phase Noise FVCO Vtune 9000 0 04 9100 0 18 9200 0 338 9300 0 518 9400 0 726 9500 0 973 9600 1 26 9700 1 602 9800 2 014 9900 2 483 10000 3 01 10100 3 562 10200 4 158 10300 4 792 18 Typical Performance Measurements SNAU160C March 2014 Revised N...

Page 19: ... generate the waveform shown later in this document Figure 6 4 Setup for Ramping Example Figure 6 5 Generated Waveform at VCO 2 Output 19 SNAU160C March 2014 Revised November 2014 Typical Performance Measurements Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated ...

Page 20: ...m B Revision October 2014 to C Revision Page Changed Updated Schematic Again due to curruption Now using a GIF format 12 20 Revision History SNAU160C March 2014 Revised November 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated ...

Page 21: ...ring the warranty period to the address designated by TI and that are determined by TI not to conform to such warranty If TI elects to repair or replace such EVM TI shall have a reasonable time to repair such EVM or provide replacements Repaired EVMs shall be warranted for the remainder of the original warranty period Replaced EVMs shall be warranted for a new full ninety 90 day warranty period 3 ...

Page 22: ...io transmitter has been approved by Industry Canada to operate with the antenna types listed in the user guide with the maximum permissible gain and required antenna impedance for each antenna type indicated Antenna types not included in this list having a gain greater than the maximum gain indicated for that type are strictly prohibited for use with this device Concernant les EVMs avec antennes d...

Page 23: ... any load to the EVM output If there is uncertainty as to the load specification please contact a TI field representative During normal operation even with the inputs and outputs kept within the specified allowable ranges some circuit components may have elevated case temperatures These components include but are not limited to linear regulators switching transistors pass transistors current sense...

Page 24: ...F REMOVAL OR REINSTALLATION ANCILLARY COSTS TO THE PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES RETESTING OUTSIDE COMPUTER TIME LABOR COSTS LOSS OF GOODWILL LOSS OF PROFITS LOSS OF SAVINGS LOSS OF USE LOSS OF DATA OR BUSINESS INTERRUPTION NO CLAIM SUIT OR ACTION SHALL BE BROUGHT AGAINST TI MORE THAN ONE YEAR AFTER THE RELATED CAUSE OF ACTION HAS OCCURRED 8 2 Specific Limitations IN NO EVENT SHALL T...

Page 25: ...esponsible for compliance with all legal regulatory and safety related requirements concerning its products and any use of TI components in its applications notwithstanding any applications related information or support that may be provided by TI Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which anticipate dangerous consequences of failur...

Page 26: ...Mouser Electronics Authorized Distributor Click to View Pricing Inventory Delivery Lifecycle Information Texas Instruments LMX2492EVM ...

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