Texas Instruments LMX2492EVM User manual

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LMX2492EVM Evaluation Module
User's Guide
SNAU160E–March 2014–Revised October 2017
LMX2492EVM Evaluation Module
The LMX2492EVM is design to evaluate the performance of LMX2492. This board consists of a LMX2492
device, a LP5900-3.3V LDO, a 9.4 - 10.8 GHz VCO and a 100 MHz crystal oscillator.
The LMX2492 is a low noise 14 GHz wideband delta-sigma fractional N PLL with ramp and chirp
generation. It consists of a phase frequency detector, programmable charge pump, and high frequency
input for the external VCO. The LMX2492 supports a broad and flexible class of ramping capabilities,
including FSK and configurable piecewise linear FM modulation profiles of up to 8 segments.
Contents
1 LMX2492EVM Evaluation Module......................................................................................... 3
2 Setup .......................................................................................................................... 4

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3 Typical Measurement ....................................................................................................... 6
4 Schematic ................................................................................................................... 12
5 PCB Layout and Layer Stack-up......................................................................................... 14
6 Bill of Materials ............................................................................................................. 17
7 Troubleshooting Guide .................................................................................................... 18
Appendix A USB2ANY Firmware Upgrade................................................................................... 19
Appendix B Using Different Reference Clock................................................................................ 22
List of Figures
1 EVM Connection Diagram.................................................................................................. 4
2 Select Device in TICS Pro.................................................................................................. 5
3 Default Mode................................................................................................................. 5
4 IO Port......................................................................................................................... 5
5 Loop Filter .................................................................................................................... 6
6 Default Output................................................................................................................ 7
7 TICS Pro FSK Configuration ............................................................................................... 7
8 FSK Example................................................................................................................. 8
9 Continuous Sawtooth Ramp Configuration............................................................................... 8
10 Continuous Sawtooth Ramp Example .................................................................................... 9
11 Continuous Trapezoid Ramp Configuration.............................................................................. 9
12 Flag Out Pins Configuration .............................................................................................. 10
13 Flags Out Timing........................................................................................................... 10
14 Continuous Trapezoid Ramp Example.................................................................................. 10
15 Readback Setting .......................................................................................................... 11
16 Register Readback......................................................................................................... 11
17 LMX2492EVM Schematic (Page 1)...................................................................................... 12
18 LMX2492EVM Schematic (Page 2)...................................................................................... 13
19 PCB Layer Stack-up ....................................................................................................... 14
20 Top Layer ................................................................................................................... 14
21 GND Layer .................................................................................................................. 15
22 Power Layer ................................................................................................................ 15
23 Bottom Layer................................................................................................................ 16
24 Troubleshooting Guide .................................................................................................... 18
25 Firmware Requirement .................................................................................................... 19
26 Firmware Loader ........................................................................................................... 19
27 BSL Button.................................................................................................................. 20
28 Update Firmware ......................................................................................................... 20
29 Firmware Update Completed............................................................................................. 21
30 USB Communications ..................................................................................................... 21
31 Reference Clock Input Configuration .................................................................................... 22
List of Tables
1 Loop Filter Configuration.................................................................................................... 6
2 Bill of Materials ............................................................................................................. 17
Trademarks
All trademarks are the property of their respective owners.

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LMX2492EVM Evaluation Module
1 LMX2492EVM Evaluation Module
1.1 Evaluation Module Contents
In the box, there are:
• One LMX2492EVM board (SV601040-002).
• One USB2ANY module (HPA665-001).
• One USB cable.
• One 10-pin ribbon cable.
1.2 Evaluation Setup Requirement
The evaluation will require the following hardware and software:
• A DC power supply
• A spectrum analyzer or a signal analyzer
• A PC running Windows 7 or more recent version
• An oscilloscope (optional)
• A high quality signal generator (optional)
• A function waveform generator (optional)
• Texas Instruments Clocks and Synthesizers TICS Pro software
• Texas Instruments PLLatinum Simulator Tool (optional)
1.3 Resources
Related evaluation and development resources are as follows:
•LMX2492 datasheet
•LMX2491 datasheet
•TICS Pro software
•PLLatinum Simulator Tool (PLL Sim)

HPA665
USB2ANY
Texas Instruments
50 
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2 Setup
2.1 Connection Diagram
Figure 1. EVM Connection Diagram
2.2 Power Supply
Apply 5-V to Vcc_5V SMA connector. The on-board VCO and the optional op-amp require 5-V supply
while the on-board XO and LMX2492 need 3.3-V supply. The on-board LDO regulates 5-V down to 3.3-V.
Never apply more than 6-V to Vcc_5V SMA connector or otherwise the LDO will be damaged. The total
current consumption of the board is about 240 mA.
2.3 Reference Clock
By default, the board is operated with the on-board 100-MHz CMOS XO. If required, the board can be
modified to operate with an external clock source. In this case, apply a single-ended clock to the OSCin
SMA connector or apply a differential clock to both OSCin and OSCin* SMA connectors. See Appendix B
for details.
2.4 RF Output
Connect RFout/2 SMA connector to a spectrum analyzer or a signal analyzer. By default, the output signal
frequency is 4.8 GHz and the amplitude is about –3 dBm. Because the frequency accuracy of the on-
board XO is 25 ppm, RF output frequency may also be off by 25 ppm. The phase noise of the XO is not
bad but not excellent, as a result, RF output phase noise may not look very good.
2.5 Programming
Connect the uWire header to a PC using the USB2ANY module. The firmware of the USB2ANY may not
be up-to-date. In this case, follow the procedures outlined in Appendix A to get it updated.
2.6 Evaluation Software
Download and install TICS Pro to a PC. Run the software and follow the following steps to get started.
1. Go to "Select Device" →"PLL" →LMX2492

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Figure 2. Select Device in TICS Pro
2. Go to "Default configuration" →"Default Mode xxxx-xx-xx"
Figure 3. Default Mode
2.7 EVM Strap Options
The MUXout pin is not connected to the uWire header but is used as the lock detect indicator. Other IO
pins, such as TRIG1, TRIG2 and MOD are connected to the uWire header. They could be used as the
input trigger sources or output flag indicators during frequency ramping.
Figure 4. IO Port

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3 Typical Measurement
3.1 Default Configuration
3.1.1 Loop Filter
The parameters for the loop filter are:
Table 1. Loop Filter Configuration
PARAMETER VALUE
VCO frequency 9.4 - 10.8 GHz
VCO gain 240 MHz/V
Effective charge pump gain 3.1 mA
Phase detector frequency 100 MHz
Loop bandwidth 435 kHz
Phase margin 60.8 degrees
C1_LF 68 pF
C2_LF 3.9 nF
C3_LF 150 pF
C4_LF Open
R2_LF 390 Ω
R3_LF 150 Ω
R4_LF 0 Ω
Figure 5. Loop Filter
3.1.2 Typical Output
1. Follow Section 2 to setup the evaluation.
2. Go to "USB communications" →"Write All Registers" to write all the registers to LMX2492.
Default output is 4.8 GHz at RFout/2 SMA connector.

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Figure 6. Default Output
3.2 Additional Tests
3.2.1 Frequency Shift Keying (FSK) Example
FSK operation requires an external input trigger signal at either MOD, TRIG1 or TRIG2 pin. In this
example, MOD pin is selected as the Trigger A source. A 20 kHz square-wave clock will be applied to
MOD pin to toggle the RF output to switch between 9600 MHz and 9604 MHz. That is, FSK deviation is 4
MHz.
Figure 7. TICS Pro FSK Configuration

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Figure 8. FSK Example
3.2.2 Continuous Sawtooth Ramp Example
This example shows how to generate a continuous sawtooth ramp. Only one ramp segment is necessary
as it will loop back to itself.
Figure 9. Continuous Sawtooth Ramp Configuration

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Figure 10. Continuous Sawtooth Ramp Example
3.2.3 Continuous Trapezoid Ramp Example
This is a long-ramp example, the ramp duration is 1 ms. RAMPx_DLY is enabled so that the ramp
generator will ramp every 2 phase detector cycles. Output flags are turned on to indicate the start of a
ramp.
Figure 11. Continuous Trapezoid Ramp Configuration

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Figure 12. Flag Out Pins Configuration
Figure 13. Flags Out Timing
Figure 14. Continuous Trapezoid Ramp Example

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3.2.4 Register Readback
To read back the written register values,
1. Remove R75 so that the MUXout pin is disconnected from the LED.
2. Populate R68 to connect MUXout pin to USB2ANY.
3. In TICS Pro, set MUXout pin to "Output Readback".
Figure 15. Readback Setting
4. Click on the Register Name that you want to read back.
5. Click the Read Register button to read back the register value.
Figure 16. Register Readback

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4 Schematic
Figure 17. LMX2492EVM Schematic (Page 1)

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Figure 18. LMX2492EVM Schematic (Page 2)

Top layer
RO4003 (Er = 3.38)
16 mil
GND layer
FR4 (Er = 4.6)
Power layer
FR4 (Er = 4.6)
Bottom layer
62 mil
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5 PCB Layout and Layer Stack-up
5.1 PCB Layer Stack-up
The top layer is 1 oz copper.
Figure 19. PCB Layer Stack-up
5.2 PCB Layout
Figure 20. Top Layer

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Figure 21. GND Layer
Figure 22. Power Layer

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Figure 23. Bottom Layer

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6 Bill of Materials
Table 2. Bill of Materials
DESIGNATOR QUANTITY DESCRIPTION PART NUMBER MANUFACTURER
C1, C2 2 CAP, CERM, 10 pF, 50 V, ±5%,
C0G/NP0, 0402 500R07S100JV4T Johanson Technology
C1_LF 1 CAP, CERM, 68 pF, 50 V, ±5%,
C0G/NP0, 0603 C0603C680J5GACTU Kemet
C2_LF 1 CAP, CERM, 3900 pF, 50 V, ±5%,
C0G/NP0, 0603 GRM1885C1H392JA01D MuRata
C3, C11 2 CAP, CERM, 1 µF, 16 V, ±10%, X7R,
0603 C1608X7R1C105K TDK
C3_LF 1 CAP, CERM, 150 pF, 50 V, ±5%,
C0G/NP0, 0603 C0603C151J5GACTU Kemet
C4 1 CAP, CERM, 0.1 µF, 50 V, ±10%,
C0G/NP0, 0402 C1005X7R1H104K TDK
C6, C7, C8, C9, C10 5 CAP, CERM, 0.1 µF, 16 V, ±5%, X7R,
0603 0603YC104JAT2A AVX
C13, C14, C15 3 CAP, CERM, 100 pF, 50 V, ±5%,
C0G/NP0, 0603 C0603C101J5GACTU Kemet
C18, C20, C22, C23, C24 5 CAP, CERM, 10 µF, 6.3 V, ±20%, X5R,
0603 C0603C106M9PACTU Kemet
D1 1 LED, Green, SMD SML-LX2832GC-TR Lumex
L1, L2, L3, L4, L5, L6, L7, L8 8 3 A Ferrite Bead, 120 Ω@ 100 MHz,
SMD BLM18SG121TN1D MuRata
OSCin, Vcc_5V 2 Connector, SMT, End launch SMA 50 Ω142-0701-851 Emerson Network
Power Connectivity
R1 1 RES, 51 Ω, 5%, 0.063 W, 0402 CRCW040251R0JNED Vishay-Dale
R2, R6, R7 3 RES, 18 Ω, 5%, 0.063 W, 0402 CRCW040218R0JNED Vishay-Dale
R2_LF 1 RES, 390 Ω, 5%, 0.1 W, 0603 CRCW0603390RJNEA Vishay-Dale
R3 1 RES, 68 Ω, 5%, 0.063 W, 0402 CRCW040268R0JNED Vishay-Dale
R3_LF 1 RES, 150 Ω, 5%, 0.1 W, 0603 CRCW0603150RJNEA Vishay-Dale
R4 1 RES, 36 Ω, 5%, 0.063 W, 0402 CRCW040236R0JNED Vishay-Dale
R4_LF, R15, R17, R18, R29, R30, R31,
R32, R33, R35, R40, R44, R51, R60 14 RES, 0 Ω, 5%, 0.1 W, 0603 CRCW06030000Z0EA Vishay-Dale
R8, R10, R19, R21, R22, R23, R25, R50 8 RES, 18 Ω, 5%, 0.1 W, 0603 CRCW060318R0JNEA Vishay-Dale
R9, R20, R24 3 RES, 68 Ω, 5%, 0.1 W, 0603 CRCW060368R0JNEA Vishay-Dale
R28 1 RES, 10 Ω, 5%, 0.1 W, 0603 CRCW060310R0JNEA Vishay-Dale
R56, R58, R61, R64, R65, R70, R72 7 RES, 12k Ω, 5%, 0.1 W, 0603 CRCW060312K0JNEA Vishay-Dale
R57, R59, R62, R63, R66, R69, R71 7 RES, 10k Ω, 5%, 0.1 W, 0603 CRCW060310K0JNEA Vishay-Dale
R75 1 RES, 330 Ω, 5%, 0.1 W, 0603 RC0603JR-07330RL Yageo America
RFout, RFout/2 2 Connector, SMT, End launch SMA 50 Ω142-0701-851 Emerson Network
Power
U1 1 500 MHz to 14 GHz Wideband, Low
Noise Fractional N PLL With Ramp/Chirp
Generation
LMX2492QRTWRQ1 Texas Instruments
U2 1 Voltage Controlled Oscillator 9.4 - 10.8
GHz MAOC-009265-TR0500 MACOM
U6 1 Ultra Low Noise, 150 mA Linear
Regulator for RF/Analog Circuits
Requires No Bypass Capacitor
LP5900SD-3.3 Texas Instruments
uWire 1 Header (shrouded), 100mil, 5x2, Gold
plated, SMD 52601-S10-8LF FCI
Y2 1 OSC 100.0000 MHz 3.3 V ±25 PPM
SMD CWX813-100.0M Connor-Winfield

Device locked Congratulation!
Start
Yes
Verify hardware setup:
x Validate power supply is connected, turned on, and current limit is appropriate for the device.
x Validate OSCin signal is supplied and turned on, if required.
x Ensure programming cable is hooked up to the board.
x Ensure spectrum analyzer center frequency matches target frequency. Choose wide span so that the carrier can
be seen if it is off frequency.
x Ensure device is not powered down by the CE pin.
x Load all registers (Ctrl+L).
Device locked Congratulation!
No
Yes
Verify software setup:
x 5HYHUWWRGHIDXOWPRGHLQWKHVRIWZDUHXQGHU³'HIDXOW&RQILJXUDWLRQ´.
x Validate that no boxes are red. If so, mouse over and read the tool tips.
x Ensure that all the frequency boxes values are correct. Also understand that the VCO frequency could be
different than the output frequency as there are often dividers after the boxes.
x Load all registers (Ctrl+L).
x Try Readback at this point, if necessary.
Device locked Congratulation!
No
Yes
Verify communications:
x *RWR³86%&RPPXQLFDWLRQV´, ³,QWHUIDFH´, ensure that the USB2ANY button is turned green. &OLFN³,GHQWLI\´WR
have the program blink the green LED.
x Send simple one way communication to the device such as: POWERDOWN, RESET, or change the status of a
pin. Realize that if a RESET is done, do a Ctrl+L to refresh the registers afterwards. For POWERDOWN, you can
validate this looking at the current on the power supply.
Device locked Congratulation!
No
Yes
No
Contact TI support
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7 Troubleshooting Guide
If the EVM does not work as expected, use the following chart to identify potential root causes. Couples of
thing to note:
• Make modifications to the EVM or change the default settings until AFTER it is verified to be working.
• Register readback requires the correct hardware and software setup. See Section 3.2.4 for details.
• The POR current of the LMX2492EVM is approximately 175 mA.
• The powerdown current of the LMX2492EVM is approximately 175 mA.
Figure 24. Troubleshooting Guide

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USB2ANY Firmware Upgrade
Appendix A
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USB2ANY Firmware Upgrade
Usually when the USB2ANY module is used at the first time, TICS Pro will request for a firmware update.
Simply follow the pop-up instructions to complete the update. This is necessary to ensure that the USB
connection between the PC and the USB2ANY module is properly setup, otherwise the programming to
LMX2492EVM will not be successful.
1. When you see this message, click the "OK" button.
Figure 25. Firmware Requirement
2. Next, follow the on-screen procedure.
Figure 26. Firmware Loader

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USB2ANY Firmware Upgrade
3. If you don't know the location of the BSL button, click the long button in the middle of the screen.
Figure 27. BSL Button
4. Click the "OK" button to go back to the previous screen. Follow the on-screen procedure until the
below screen is pop-up.
Figure 28. Update Firmware