Texas Instruments LMX2594, User Manual

Page 1: ...LMX2594 EVM Instructions 15 GHz Wideband Low Noise PLL With Integrated VCO User s Guide Literature Number SNAU210 March 2017 ...

Page 2: ...ck State 9 5 Current Loop Filter Configuration 11 6 Key Results to Expect 12 Appendix A Schematic 13 Appendix B Bill of Materials 14 Appendix C Board Layers Stack Up 16 Appendix D Changing Reference Oscillator and Setup 17 Appendix E Connecting Reference Pro 19 Appendix F Ramping Feature 22 F 1 Ramping Example Waveform 22 Appendix G SYSREF Feature 24 Appendix H VCO Calibration 29 Appendix I Enabli...

Page 3: ...right 2017 Texas Instruments Incorporated LMX2594 EVM Instructions 15 GHz Wideband Low Noise PLL With Integrated VCO User s Guide SNAU210 March 2017 LMX2594 EVM Instructions 15 GHz Wideband Low Noise PLL With Integrated VCO Figure 1 LMX2594EVM 1 Trademarks ...

Page 4: ... 708 100 MHz on board oscillator enabled default To use another reference see Appendix D 3 Programming Interface Reference Pro will provide SPI interface to program LMX2594 a Connect USB cable from laptop or PC to USB port in Reference Pro This provides power to Reference Pro Board and communication with TICS GUI b Connect 10 pin ribbon cable from Reference Pro to LMX2594EVM as shown above 4 Outpu...

Page 5: ...5 SNAU210 March 2017 Submit Documentation Feedback Copyright 2017 Texas Instruments Incorporated LMX2594 EVM Instructions 15 GHz Wideband Low Noise PLL With Integrated VCO 3 EVM Description The LMX2594 is populated on a 4 layer PCB This brief description should help you use the EVM Figure 3 LMX2594EVM Description The serial interface pin description is as follow Table 1 EVM and Serial Interface Co...

Page 6: ... March 2017 Submit Documentation Feedback Copyright 2017 Texas Instruments Incorporated LMX2594 EVM Instructions 15 GHz Wideband Low Noise PLL With Integrated VCO The LD switch should be on to enable Lock indicator Figure 4 LD Lock Detect ...

Page 7: ...ing the Software 1 Download TICS Pro from the TI Website at www ti com tool TICSPRO SW 2 Install it by following the wizard 3 Search for LMX2594 Click on Select Device From menu bar PLL VCO LMX2594 Figure 5 Search for LMX2594 on TICS Pro 4 You are now ready to use this software Verify that you can communicate with Reference Pro Select interface under USB communications Figure 6 USB Communications ...

Page 8: ...dback Copyright 2017 Texas Instruments Incorporated LMX2594 EVM Instructions 15 GHz Wideband Low Noise PLL With Integrated VCO 5 Click on identify and you should see the LED MSP430 Supplied Blink on Reference Pro Figure 7 USB Communication Between TICS Pro and Reference Pro ...

Page 9: ...ation Feedback Copyright 2017 Texas Instruments Incorporated LMX2594 EVM Instructions 15 GHz Wideband Low Noise PLL With Integrated VCO 4 Bringing LMX2594 to a Lock State Load the default mode by selecting it as shown in Figure 8 Figure 8 TICS Pro GUI LMX2594 Default Configuration ...

Page 10: ...7 Texas Instruments Incorporated LMX2594 EVM Instructions 15 GHz Wideband Low Noise PLL With Integrated VCO For best results in the User Controls Tab in TICS Pro Under General Controls check and uncheck the Reset box After the reset Write all registers as shown in Figure 9 Figure 9 TICS Pro Write All Registers ...

Page 11: ...Loop Filter Configuration PARAMETER VALUE VCO Gain 132 MHz V Loop Bandwidth 285 kHz Phase Margin 65 deg C1_LF 390 pF C2_LF 68 nF C3_LF Open C4_LF 1800 pF R2 68 Ω R3_LF 0 Ω R4_LF 18 Ω Effective Charge Pump Gain 15 mA Phase Detector Frequency MHz 200 MHz VCO Frequency Designed for 15 GHz but works over the whole frequency range Figure 10 Current Loop Filter Configuration For detailed design and simu...

Page 12: ...d LMX2594 EVM Instructions 15 GHz Wideband Low Noise PLL With Integrated VCO 6 Key Results to Expect Figure 11 Phase Noise Plot at 14 GHz Output Frequency This assumes that the input reference is very clean such as a 100 MHz Wenzel oscillator A signal generator is NOT sufficiently clean The LMX2594 requires an external reference ...

Page 13: ...13 SNAU210 March 2017 Submit Documentation Feedback Copyright 2017 Texas Instruments Incorporated Schematic Appendix A SNAU210 March 2017 Schematic Figure 12 Schematic ...

Page 14: ...16T 6 C13 C18 C23 C24 C26 C27 C28 C29 CAP CERM 1 µF 16 V 10 X7R 0603 TDK C1608X7R1C105K080AC 8 C19 C20 C21 C22 C25 CAP CERM 10 µF 10 V 20 X5R 0603 TDK C1608X5R1A106M080AC 5 CE_TP CSB_TP GND_TP MUXout_TP RampCLK_TP RampDIR_TP SCK_TP SDI_TP SYNC_TP SysRefReq_TP Vcc_TP VccRF_TP Vtune_TP Test Point Compact White TH Keystone 5007 13 Cin_0 CAP CERM 10 µF 25 V 10 X5R 0805 MuRata GRM219R61E106KA12D 1 Cout...

Page 15: ... 1 0 1 W 0603 Vishay Dale CRCW0603562KFKEA 1 RFoutAM RFoutAP RFoutBM RFoutBP JACK SMA 50 Ω Gold Edge Mount Johnson 142 0771 831 4 U1 High Performance Wideband PLLatinum RF Synthesizer RHA0040A VQFN 40 Texas Instruments LMX2594RHAR 1 U3 Buck Step Down Regulator with 3 to 17 V Input and 0 9 to 6 V Output 40 to 85 C 16 Pin QFN RGT Green RoHS and no Sb Br Texas Instruments TPS62150RGTR 0 uWire Header ...

Page 16: ...2017 Submit Documentation Feedback Copyright 2017 Texas Instruments Incorporated Board Layers Stack Up Appendix C SNAU210 March 2017 Board Layers Stack Up Total Board thickness is 62 mils Figure 13 Board Layer Stack Up ...

Page 17: ...rence Oscillator Requirements 100 MHz REFERENCE MINIMUM REQUIREMENTS FOR A 0 4 dB IMPACT ON PLL INBAND PN 1 Offset Hz 100 1k 10k 100k Noise level dBc Hz 139 149 159 164 There are different options to provide a reference oscillator to LMX2594 Use on board oscillator default Enable LMK61xx from Reference Pro PCB use external oscillator By default the onboard oscillator is enabled To use external ref...

Page 18: ...opyright 2017 Texas Instruments Incorporated Changing Reference Oscillator and Setup For single ended 1 Switch R24b to R24 2 Switch R29b to R29 3 Must remove R33 to remove power from oscillator 4 Populate R25 and R30 5 Remove R32 Figure 15 Differential Reference Configuration ...

Page 19: ... Header Figure 17 LMX2594EVM Setup With Reference Pro The LMK61PD0A2 has several control pins dedicated for control of output format output frequency and output enable control These control pins can be configured through the jumpers shown in Table 5 and Table 6 Jumpers FS1 FS0 OS and OE can be used to configure the corresponding control pin to either high or low state by strapping the center pin t...

Page 20: ...the output type from Table 6 Table 7 lists component values for each configuration 1 50 Ω to VCC 2 V termination is required on receiver 2 100 Ω differential termination R31 is provided on Reference Pro PCB Removing the differential termination on the EVM is possible if the differential termination is available on the receiver Table 7 Output Termination Schemes OUTPUT FORMAT COUPLING COMPONENT VAL...

Page 21: ...www ti com Appendix E 21 SNAU210 March 2017 Submit Documentation Feedback Copyright 2017 Texas Instruments Incorporated Connecting Reference Pro Figure 18 LMK61PD0A2 Output Termination ...

Page 22: ...ruments Incorporated Ramping Feature Appendix F SNAU210 March 2017 Ramping Feature F 1 Ramping Example Waveform VCO is ramping from 8 to 10 GHz and being dividing by 4 so that it can be seen with the HP53310A This can be set up on the ramp GUI tab Figure 19 Ramping Example Tics ...

Page 23: ...www ti com Ramping Example Waveform 23 SNAU210 March 2017 Submit Documentation Feedback Copyright 2017 Texas Instruments Incorporated Ramping Feature Figure 20 Ramping Example ...

Page 24: ...struments Incorporated SYSREF Feature Appendix G SNAU210 March 2017 SYSREF Feature 1 Bring LMX2594 to a Lock State 2 Perform Sync Figure 21 Perform Sync For SysRef 3 Configure TICS Pro PLL tab for SysRef Check the SYSREF_EN box Change OUTB_MUX to SysRef Uncheck the OUT_PD box ...

Page 25: ... Texas Instruments Incorporated SYSREF Feature Figure 22 Configure and Enable SysRef 4 Confirm the Interpolator Frequency is between 800 MHz and 1500 MHz If not change the SYSREF_DIV_PRE drop down to Div2 or Div4 to reach an appropriate Interpolator Frequency for the current configuration ...

Page 26: ...March 2017 Submit Documentation Feedback Copyright 2017 Texas Instruments Incorporated SYSREF Feature Figure 23 Interpolator Frequency For SysRef 5 Go to User Controls in the side bar and check the SysRefReq box under the Pins section ...

Page 27: ...NAU210 March 2017 Submit Documentation Feedback Copyright 2017 Texas Instruments Incorporated SYSREF Feature Figure 24 Check SysRefReq Box on User Controls Tab 6 To modify SysRef Frequency change the value in the SYSREF_DIV box ...

Page 28: ...gh Default mode See quick start instructions Master Pulse LMX2594 generates a finite number of pulses as long as the SysRefReq pin is held high Note SysRefReq must be held high for the duration of the pulses Uncheck SysRefReq under Pins in User Controls tab Check SYSREF_PULSE Set SYSREF_PULSE_CNT to desired number of pulses Check SysRefReq under Pins in User Controls tab Repeater RFOUTB will repea...

Page 29: ...1 6 V 3 Set MUXOUT_SEL register R0 2 to a value of 1 for lock detect 4 Set your desired output frequency to lock to 5 Trigger the calibration with FCAL_EN register R0 3 to a value of 1 6 Observe the triggered pulse there should be a pulse from MUXout digital HIGH to LOW and back to HIGH the low indicates the instant calibration is triggered and running then high is when done calibration Adjust the...

Page 30: ...Appendix H www ti com 30 SNAU210 March 2017 Submit Documentation Feedback Copyright 2017 Texas Instruments Incorporated VCO Calibration Figure 27 Unassisted Calibration Plot ...

Page 31: ...210 March 2017 Enabling Onboard DC DC Buck Converter TPS62150 Figure 28 Resistor Configuration to Enable DC DC 1 MUST SWITCH R35 to Rtps1 2 MUST SWITCH R34 to Rtps2 3 Populate Rtps 4 DC DC circuitry was optimized for efficiency for 5 to 8 V but a voltage of 3 3 V to 17 V can be applied to VCC SMA after resistor network is configured correctly from steps above ...

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