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

www.ti.com Bringing LMX2594 to a Lock State
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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

Bringing LMX2594 to a Lock State www.ti.com
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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

www.ti.com Current Loop Filter Configuration
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LMX2594 EVM Instructions – 15-GHz Wideband Low Noise PLL With
Integrated VCO
5 Current Loop Filter Configuration
The parameters for the loop filters are:
Table 2. Current 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 simulation, see the PLLatinum Sim Tool.
For application notes, blogs,or videos on our products, see http://www.ti.com/pll.

Key Results to Expect www.ti.com
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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.

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Schematic
Appendix A
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Schematic
Figure 12. Schematic

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Bill of Materials
Appendix B
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Bill of Materials
Table 3. Bill of Materials
DESIGNATOR DESCRIPTION MANUFACTURER PART NUMBER QUANTITY
!PCB Printed-Circuit Board Any SV601308 1
C1, C3, C9, C14,
C15, C17, C30 CAP, CERM, 0.1 µF, 16 V, ±5%, X7R, 0603 AVX 0603YC104JAT2A 7
C1_LF CAP, CERM, 390 pF, 50 V,
±5%, C0G/NP0, 0603 Kemet C0603C391J5GACTU 1
C2, C4, C8, C16 CAP, CERM, 10 µF, 10 V,
±10%, X5R, 0805 Kemet C0805C106K8PACTU 4
C2_LF CAP, CERM, 0.068 µF, 50 V,
±10%, X7R, 0603 MuRata GRM188R71H683KA93D 1
C4_LF CAP, CERM, 1800 pF, 50 V,
±5%, C0G/NP0, 0603 MuRata GRM1885C1H182JA01D 1
C5, C6, C7, C10,
C11, C12 CAP, CERM, 0.01 µF, 16 V, ±10%, X7R, 0402 AT Ceramics 520L103KT16T 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
Cout0 CAP, CERM, 22 µF, 16 V,
±10%, X5R, 0805 TDK C2012X5R1C226K125AC 1
Css CAP, CERM, 3300 pF, 50 V,
±5%, C0G/NP0, 0603 MuRata GRM1885C1H332JA01D 1
D1 LED, Green, SMD Lite-On LTST-C190GKT 1
L1, L2 Inductor, Multilayer, Air Core, 18
nH, 0.3 A, 0.36 Ω, SMD MuRata LQG15HS18NJ02D 2
L1_TPS Inductor, Shielded, Composite,
2.2 µH, 3.7 A, 0.02 Ω, SMD Coilcraft XFL4020-222MEB 1
LBL1 Thermal Transfer Printable Labels, 0.650" W x 0.200" H -
10,000 per roll Brady THT-14-423-10 1
MUXout_SW Switch, SPST, Slide, Off-On, 2
Pos, 0.1 A, 20 V, SMD CTS Electrocomponents 219-2MST 1

www.ti.com Appendix B
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Bill of Materials
Table 3. Bill of Materials (continued)
DESIGNATOR DESCRIPTION MANUFACTURER PART NUMBER QUANTITY
OSCinM, OSCinP,
SYNC, SysRef,
Vcc Connector, SMT, End launch
SMA 50 ohm Emerson Network Power Connectivity 142-0701-851 5
R1 RES, 330 Ω, 5%, 0.1 W, 0603 Yageo America RC0603JR-07330RL 1
R2 RES, 100 k, 5%, 0.1 W, 0603 Vishay-Dale CRCW0603100KJNEA 1
R2_LF RES, 68, 5%, 0.1 W, 0603 Vishay-Dale CRCW060368R0JNEA 1
R3_LF, R12, R15,
R24b, R26, R29b,
R31, R34, R35,
R36, R41, R42,
R43, R44, R45
RES, 0, 5%, 0.1 W, 0603 Vishay-Dale CRCW06030000Z0EA 15
R4_LF RES, 18, 5%, 0.1 W, 0603 Vishay-Dale CRCW060318R0JNEA 1
R5, R7, R8, R9,
R16, R19, R20,
R22 RES, 12 kΩ, 5%, 0.1 W, 0603 Vishay-Dale CRCW060312K0JNEA 8
R33 RES, 10 Ω, 5%, 0.1 W, 0603 Vishay-Dale CRCW060310R0JNEA 1
R32 RES, 100, 1%, 0.1 W, 0603 Vishay-Dale CRCW0603100RFKEA 1
R37, R38, R39,
R40 RES, 50, 0.1%, 0.05 W, 0402 Vishay-Dale FC0402E50R0BST1 4
Rfbb1 RES, 180 k, 0.1%, 0.1 W, 0603 Yageo America RT0603BRD07180KL 1
Rfbt1 RES, 562 k, 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 (shrouded), 100 mil,
5x2, Gold plated, SMD FCI 52601-S10-8LF 1
Y1 Crystal Oscillator, 100 MHz,
LVDS, 3.3V, SMD Vectron VC-708-EDE-FNXN- 100M000000 1
C3_LF CAP, CERM, 300 pF, 100 V,
±5%, C0G/NP0, 0603 MuRata GRM1885C2A301JA01D 0
FID5, FID6, FID10,
FID11 Fiducial mark. There is nothing to buy or mount. N/A N/A 0
PinControl Header, 100 mil, 4x2, Gold,
SMT Molex 0015910080 0
R3, R4, R6, R10,
R17, R18, R21,
R23 RES, 12 kΩ, 5%, 0.1 W, 0603 Vishay-Dale CRCW060312K0JNEA 0
R11, R14, R24,
R29, Rtps1, Rtps2
RES, 0, 5%, 0.1 W, 0603, RES,
0, 5%, 0.1 W, 0603, RES, 0,
5%, 0.1 W, 0603, RES, 0, 5%,
0.1 W, 0603, RES, 0 Ω, 5%,
0.1W, 0603, RES, 0 Ω, 5%, 0.1
W, 0603
Vishay-Dale CRCW06030000Z0EA 0
R13 RES, 100, 5%, 0.1 W, 0603 Vishay-Dale CRCW0603100RJNEA 0
R25, R30 RES, 51, 5%, 0.1 W, 0603 Vishay-Dale CRCW060351R0JNEA 0
R27, R28 RES, 140, 1%, 0.1 W, 0603 Vishay-Dale CRCW0603140RFKEA 0
Rtps RES, 0, 5%, 0.125 W, 0805 Vishay-Dale CRCW08050000Z0EA 0

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Board Layers Stack-Up
Appendix C
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Board Layers Stack-Up
Total Board thickness is 62 mils.
Figure 13. Board Layer Stack-Up

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Changing Reference Oscillator and Setup
Appendix D
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Changing Reference Oscillator and Setup
The reference can be single-ended or differential. To measure the performance of the PLL ONLY,
the reference should have at least this level of performance. We understand that this can be a
challenge at 100-Hz offset:
(1) A noise source 10 dB down from the PLL noise will contribute to raise the noise by 0.4 dB.
Table 4. Reference 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 reference, onboard oscillator must be
disabled. Having multiple 100 MHz enabled or powered sharing VCC or Gnd will degrade the phase noise
performance of LMX2594.
For differential pair connection:
1. Switch R24b to R24.
2. Switch R29b to R29
3. Must remove R33 to remove power from oscillator
Figure 14. Single-Ended Reference Configuration

Appendix D www.ti.com
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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

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Connecting Reference Pro
Appendix E
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Connecting Reference Pro
1. To use Reference Pro, change the configuration for SE or differential connection as shown on
Appendix D.
2. Change jumper position on Reference Pro, connect middle pin of OE header to Vdd.
Figure 16. Reference Pro Output Enable 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 to VDD position (tie pins 2-3) or GND position (tie pins 1-2),
respectively. Connections from the VDD position to the device supply or from the GND position to the
ground plane are connected by 1.5-kΩresistors.

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Connecting Reference Pro
Table 5. Output Frequency of LMK61PD0A2 (Reference Pro)
FS1 FS0 OUTPUT FREQUENCY (MHz)
0 0 100
0 NC 312.5
0 1 125
NC 0 106.25
NC NC 156.25
NC 1 212.5
1 0 62.5
Table 6. OutputType of LMK61PD0A2 (Reference Pro)
OS OE OUTPUT TYPE
X O Disabled (PLL Functional)
0 1 LVPECL
NC 1 LVDS
1 1 HCSL
The OS pin is used to bias internal drivers and change the output type. It is imperative to match the output
termination passive components as shown on Table 7 with the output type from Table 6.
Table 7 lists component values for each configuration.
(1) 50 Ωto VCC – 2? V termination is required on receiver.
(2) 100-Ωdifferential 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 VALUE
LVPECL AC
(default EVM
configuration)
R25, R28 0 Ω
R26, R29 150 Ω
C24, C25 0.01 uF
R27, R30, R31 DNP
DC(1) R25, R28, C24, C25 0 Ω
R26, R29, R27, R30, R31 DNP
LVDS(2) AC R25, R28, R27, R30 0 Ω
R31 100 Ω
C24, C25 0.01 uF
R26, R29 DNP
DC R25, R27, R28, R30, C24, C25 0 Ω
R31 100 Ω
R26, R29 DNP
HCSL AC R25, R28 0 Ω
R26, R29 50 Ω
C24, C25 0 Ω
R27, R30, R31 DNP
DC R25, R28 0 Ω
R26, R29 50 Ω
C24, C25 0.01 uF
R27. R30, R31 DNP