Texas Instruments LMX248 Series, LMX2485E-EVM, LMX2485E, LMX2487E-EVM, LMX2486 User Manual

LMX248x Evaluation Board

User's Guide

Literature Number: SNAU137B

March 2014–Revised July 2018

Contents

1 Trademarks......................................................................................................................... 4

2 Introduction......................................................................................................................... 4

3 Setup.................................................................................................................................. 5

3.1 Input/Output Connector Description ................................................................................... 5

3.2 Loop Filter Values........................................................................................................ 6

3.3 RF PLL Loop Filter....................................................................................................... 6

3.4 Installing the EVM Software ............................................................................................ 6

3.5 Using the EVM Software ................................................................................................ 7

4 Schematic........................................................................................................................... 8

5 Bill of Materials.................................................................................................................... 9

6 Layers Stackup .................................................................................................................. 11

7 PCB Layouts...................................................................................................................... 11

8 Typical Phase Noise Performance Plots................................................................................ 15

8.1 LMX2485E Phase Noise Plots........................................................................................ 15

8.2 LMX2487E Phase Noise Plots........................................................................................ 18

Revision History.......................................................................................................................... 21

2

Table of Contents

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SNAU137B–March 2014–Revised July 2018

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User's Guide

SNAU137B–March 2014–Revised July 2018

LMX248x Evaluation Board

The Texas Instruments LMX2485E-EVM/LMX2487E-EVM helps designers evaluate the operation and
performance of any device in the LMX248x family. Although only two options are offered, the other
members in the family are all pinout-compatible and program-compatible to one of these existing board
option. They would be expected to have similar performance, just different in the maximum frequency of
operation.

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LMX248x Evaluation Board

3

Introduction

1 Trademarks

All trademarks are the property of their respective owners.

2 Introduction

The EVM contains one Frequency Synthesizer (see Table 1).

LMX2485E 50 to 3000 MHz

LMX2485 500 to 3000 MHz
LMX2486 1000 to 4500 MHz

LMX2487E 3000 to 7500 MHz

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Table 1. Evaluation Device and Package Configurations

DEVICE RF PLL FREQUENCY RANGE EVALUATION VEHICLE

LMX2485E EVAL

LMX2487E EVALLMX2487 1000 to 6000 MHz

Table 2. Evaluation Device and Package Configurations

BOARD

VERSION

LMX2485E-

EVM

LMX2487E-

EVM

DESIGNATOR IC PACKAGE VCO MODEL

U1 LMX2485E QFN24 Crystek CVCO55CL 60-80 MHz

U1 LMX2487E QFN24 Crystek CVCO44BH 4100-4300 MHz

VCO FREQUENCY

RANGE

Although the devices are very broadband, the VCO is ultimately what limits the frequency range of the
evaluation board. These VCOs were chosen primarily for their availability, standard footprint, and for their
lower risk of becoming obsolete.

4

LMX248x Evaluation Board

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Spectrum

Analyzer

5 V

Input Reference

Frequency

10 pin Header

from

USB2ANY

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3 Setup

3.1 Input/Output Connector Description

Setup

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Figure 1. Evaluation Board Setup

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LMX248x Evaluation Board

5

Setup

VccVCO

Connect this to a 5-V Power supply.

OSCin

Connect this to a signal generator at +4 dBm. Default frequency is 50 MHz for the LMX2485E-EVM
and 100 MHz for the LMX2487E-EVM.

RFout

Connect this to a spectrum analyzer. The board has DC-blocking capacitors, so the signal is AC
coupled.

uWire

Hook this to the programming interface.

3.2 Loop Filter Values

TI’s Clock Design Tool can be used to optimize the PLL phase noise/jitter for given specifications. See:

http://www.ti.com/tool/pllatinumsim-sw.

3.3 RF PLL Loop Filter

VCO Gain (K

VCO Input Capacitance 330 pF 10 pF

Nominal Output Frequency 60 to 80 MHz 4100 to 4300 MHz

Reference Clock Frequency 50 MHz 100 MHz

KPD(Charge Pump) 16X (1520 μA) 8X (760 μA)

Phase Detector Freq 2000 kHz 20000 kHz

Table 3. RF PLL Loop Filter Parameters

Parameter LMX2485E LMX2487E

VCO Used Crystek CVCO55CL Crystek CVCO55BH

) 8 MHz/V 100 MHz/V

VCO

Phase Margin 44 50

Loop Bandwidth 8.7 15

PLL Supply 3.3 V from LDO 3.3 V from LDO

VCO Supply 5 V 5 V

C1 10 nF 5.6 nF
C2 680 nF 120 nF
C3 15 nF 220 pF
C4 1 nF 1 nF
R2 180 Ω 270 Ω
R3 220 Ω 1.2 kΩ
R4 3.3 k Ω 1.2 k Ω

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NOTE: PLL Loop Bandwidth is a function of KPD, K

and N will thereforechange the loop bandwidth.

3.4 Installing the EVM Software

1. Go to http://www.ti.com/tool/ticspro-sw

2. Click on the download button to download the software.

3. Run the executable file.

6

LMX248x Evaluation Board

, N, and the loop components. Changing K

VCO

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PD

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3.5 Using the EVM Software

Figure 2. Choosing the LMX2487E Device in TICS Pro

Setup

NOTE: Don’t forget to press <Cntrl>+L or do Keyboard Controls → Load Device, to load the settings

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LMX248x Evaluation Board

7

18

R41

1

234

5

VccVCO

142-0701-851

VccRFAMP

VccIFVCO

0

R1

0.1µF

C7

VddRF3

0

R2

0.1µF

C3

VddRF4

0

R4

0.1µF

C2

VddRF2

18

R40

18

R38

0.1µF

C1

0.1µF

C11

0

R6

1

234

5

IFout

142-0701-851

0.1µF

C8

VddIF1

0

R7

220

R3_RF

3.3k

R4_RF

18

R29

0

R3_IF

27k

R37

8.2k

R2_IF

0

R2pRF

180

R2_RF

15k

R32

15k

R34

15k

R35

2.2k

R36

1800pF

C1_IF

0.1µF

C25

100pF

C32

100pF

C30

1

234

5

RFout

142-0701-851

100pF

C3_IF

0.01µF

C2_IF

0.01µF

C2pIF

0.01µF

C1_RF

0.015µF

C3_RF

1000pF

C4_RF

100pF

C34

0.1µF

C36

0.68µF

C2_RF

100pF

C39

1

234

5

OSCin

142-0701-851

27k

R52

15k

R39

15k

R51

27k

R53

27k

R33

0.1µF

C12

VddRF1

27k

R42

VccPLL

VccPLL

VccRFVCO

VccIFVCO

VddRF1

VddIF1

68

R28

0

R10

0.1µF

C9

VddIF2

4700pF

C2pRF

0

R21

Note

-------

- Any component with designator value of 100 or higher is on the back side of the board and will not be placed in default mode.

- The components with a suffix of "p" indicate a pad is shared and the part number without the "p" suffix can not be placed.

--- R27p Place 68 ohms to ground to create a 6 dB T pad, or 0 ohms for impedance measurent callibration.

--- R33p Place this component to use the directional coupler

--- R35p Place 68 ohms to ground to create a 6 dB T pad, or 0 ohms for impedance measurent callibration.

100pF

C33

68

R44

VccIFAMP

IN6OUT

1

GND

3

EN

4

NC

5

DAP

7

NC

2

U3

LP5900SDX-3.3

4

3

2

1

5

V+
V-

U4

LM6211MF

4

3

2

1

5

V+

V-

U5

LM6211MF

10µF C19

VccRFVCO

0.1µF

C10

VccPLL

0.1µF

C5

VccRFAMP

0.1µF

C17

10k

R24

10k

C21

VccPLL

0.1µF

C20

10k

R30

1µF

C27

VccPLL

VccIFAMP

0.1µF

C23

0

R26

1.00k

R25

1

234

5

VccAUX

142-0701-851

0

R23

0

R54

0

R20

0

R55

0

R22

FID2 FID1

FID3

LOGO

PCB

Texas Instruments

LOGO

PCB

ESD Susceptible

S1

TCBS-6-01

S3

TCBS-6-01

S2

TCBS-6-01

S4

TCBS-6-01

0

R5

0R80

R9

0

R12

0

R16

0

R190R18

0

R15

0

R11

0

R3

SV600806
B

PCB Number:

PCB Rev:

Label Table

Variant Label Text

001 LMX2485E EVAL

002 LMX2487E-EVM

CE

10

CLK

8

DATA

7

ENOSC

19

FINRF

5

FINIF

13

FINRF

4

LE

6

OSCIN

20

CPOUTIF

16

CPOUTRF

1

FLOUTRF

23

FTEST/LD

12

OSCOUT

18

VDDIF1

14

VDDIF2

17

VDDRF1

3

VDDRF2

9

VDDRF3

22

VDDRF4

24

VDDRF5

11

GND

2

GND

15

NC

21

GND

25

U1

LMX2485ESQ/NOPB

10µF

C4

1 2
3 4
5 6
7 8
9 10

uWire

52601-S10-8LF

TP_VtuneRF

TP_OSCout

TP_Ftest/LD

TP_VtuneIF

21 ohm

L1

21 ohm

L2

1

MH1

1

MH2

1

MH3

1

MH4

0.1µF

C14

1.00k

R17

GND

3

Vtune

2

GND

1

GND

7

GND

6

GND

5

GND

8

GND

4

GND9RFout10GND11GND

12

GND

13

Vcc

14

GND

15

GND

16

60-110MHz

U2

GND

3

Vtune

2

GND

1

GND

7

GND

6

GND

5

GND

8

GND

4

GND9RFout10GND11GND

12

GND

13

Vcc

14

GND

15

GND

16

60-110MHz

U6

51

R14

100pF

C26

0.1µF

C29

18

R31

18

R27

0.1µF

C28

27k

R46

100pF

C37

VccPLL

27k

R47

100pF

C31

VddIF2

100pF

C24

VddRF2

100pF

C35

VddRF3

100pF

C18

VddRF4

100pF

C22

VddRF5

100pF

C38

VddRF5

0.1µF

C13

0

R13

TP_CE

TP_GND

TP_CLK

TP_DATA

TP_LE

TP_ENOSC

15k

R45

0.1µF

C15

10µF

C6

Green

12

D1

270

R43

VccPLL

1

2 3

Q1
BSS138

15k

R48

LOGO

PCB

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Schematic

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8

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LMX248x Evaluation Board

4 Schematic

View Section 5 for actual component values.

Figure 3. LMX2485E/87E EVM Schematic