Texas Instruments LMX2594 User manual

LMX2594 EVM Instructions – 15-GHz Wideband
Low Noise PLL With Integrated VCO
User's Guide
Literature Number: SNAU210
March 2017

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Table of Contents
Contents
1 Trademarks......................................................................................................................... 3
2 Evaluation Board Setup ....................................................................................................... 4
3 EVM Description .................................................................................................................. 5
3.1 Installing the Software................................................................................................... 7
4 Bringing LMX2594 to a Lock 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 Enabling Onboard DC-DC Buck Converter (TPS62150) .................................................. 31

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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

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LMX2594 EVM Instructions – 15-GHz Wideband Low Noise PLL With
Integrated VCO
2 Evaluation Board Setup
Figure 2. LMX2594EVM Setup
SPACER
1. Power:
a. Set power supply to 3.3 V with 600-mA current limit and connect to VCC SMA.
2. Input Signal:
a. VC-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. Output:
a. Connect RFoutAM or RFoutAP to a phase noise Analyzer. Connect a 50-Ωon the unused output if
you are using only single-ended. Use a balun if you are using differential.

Voltage Regulator
Not Enabled
Diff. RF Output A
Diff. RF Output B
LMX2594
100 MHz XO
Diff. Reference Input
Single Ended Signal
Can Be Used
Power Supply 3.3 Volt
Sync
Sys Ref
Lock Indicator LED
Switch to Select:
1) SPI read block
2) Lock Indicator
(1 or 2)
Loop Filter
Components (*_LF)
Serial Interface Pin-out
2 4 6 8 10
1 3 5 7 9
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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 Connector
Description
NO. NAME
1RAMPDIR and CE (Choose with
Resistors on Board)
2 CSB
3 MUXout
4 SDI
5 Not Used
6 GND
7 RampCLK
8 SCK
9 SysRefReq
10 SYNC

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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

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LMX2594 EVM Instructions – 15-GHz Wideband Low Noise PLL With
Integrated VCO
3.1 Installing 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 on TICS Pro

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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

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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

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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