Texas Instruments LMX248 Series User manual

LMX248x Evaluation Board
User's Guide
Literature Number: SNAU137B
March 2014–Revised July 2018

2SNAU137B–March 2014–Revised July 2018
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Table of Contents
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

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LMX248x Evaluation Board
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.

Introduction www.ti.com
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1 Trademarks
All trademarks are the property of their respective owners.
2 Introduction
The EVM contains one Frequency Synthesizer (see Table 1).
Table 1. Evaluation Device and Package Configurations
DEVICE RF PLL FREQUENCY RANGE EVALUATION VEHICLE
LMX2485E 50 to 3000 MHz LMX2485E EVAL
LMX2485 500 to 3000 MHz
LMX2486 1000 to 4500 MHz LMX2487E EVALLMX2487 1000 to 6000 MHz
LMX2487E 3000 to 7500 MHz
Table 2. Evaluation Device and Package Configurations
BOARD
VERSION DESIGNATOR IC PACKAGE VCO MODEL VCO FREQUENCY RANGE
LMX2485E-
EVM U1 LMX2485E QFN24 Crystek CVCO55CL 60-80 MHz
LMX2487E-
EVM U1 LMX2487E QFN24 Crystek CVCO44BH 4100-4300 MHz
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.

Spectrum
Analyzer
5 V
Input Reference
Frequency
10 pin Header
from
USB2ANY
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3 Setup
3.1 Input/Output Connector Description
Figure 1. Evaluation Board Setup

Setup www.ti.com
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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
Table 3. RF PLL Loop Filter Parameters
Parameter LMX2485E LMX2487E
VCO Used Crystek CVCO55CL Crystek CVCO55BH
VCO Gain (KVCO) 8 MHz/V 100 MHz/V
VCO Input Capacitance 330 pF 10 pF
Nominal Output Frequency 60 to 80 MHz 4100 to 4300 MHz
Phase Margin 44 50
Loop Bandwidth 8.7 15
Reference Clock Frequency 50 MHz 100 MHz
KPD(Charge Pump) 16X (1520 μA) 8X (760 μA)
Phase Detector Freq 2000 kHz 20000 kHz
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 Ω270 Ω
R3 220 Ω1.2 kΩ
R4 3.3 k Ω1.2 k Ω
NOTE: PLL Loop Bandwidth is a function of KPD, KVCO, N, and the loop components. Changing KPD
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.

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3.5 Using the EVM Software
Figure 2. Choosing the LMX2487E Device in TICS Pro
NOTE: Don’t forget to press <Cntrl>+L or do Keyboard Controls →Load Device, to load the settings

18
R41
1
2 3 4 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
2 3 4 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
2 3 4 5
RFout
142-0701-851
100pF
C3_IF
0.01 µF
C2_IF
0.01 µF
C2pIF
0.01 µF
C1_RF
0.015 µF
C3_RF
1000pF
C4_RF
100pF
C34
0.1µF
C36
0.68 µF
C2_RF
100pF
C39
1
2 3 4 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
IN
6OUT 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
10µFC19
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
2 3 4 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
0
R8
0
R9
0
R12
0
R16
0
R19
0
R18
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
GN D 3
Vtune 2
GN D 1
GND
7GND
6GND
5
GND
8
GN D 4
GN D
9
RF o ut
10
GN D
11
GN D
12
GND 13
Vcc 14
GND 15
GND 16
60-110MHz
U2
GN D 3
Vtune 2
GN D 1
GND
7GND
6GND
5
GND
8
GN D 4
GN D
9
RF o ut
10
GN D
11
GN D
12
GND 13
Vcc 14
GND 15
GND 16
60-110MHz
U6
51
R 14
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
FCC disclaimer
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Schematic www.ti.com
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4 Schematic
View Section 5 for actual component values.
Figure 3. LMX2485E/87E EVM Schematic

www.ti.com Bill of Materials
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5 Bill of Materials
Table 4. Bill of Materials
ITEM DESIGNATOR DESCRIPTION MANUFACTURER PART NUMBER QUANTITY
1 AA1 Printed Circuit Board TBD by TI 551600806-001 REV A 1
2C18, C22, C24, C26, C30, C31,
C35, C41 CAP, CERM, 100pF,
25V, +/-10%, X7R, 0603 AVX 06033C101KAT2A 8
3C5, C10, C11,
C14, C16, C17,
C25, C28, C29,
C36
CAP, CERM, 0.1uF, 16V,
+/-10%, X7R, 0603 Kemet C0603C104K4RACTU 10
4C1, C2, C3, C7,
C8, C9, C37, C40 CAP, CERM, 1uF, 16V, +/-10%, X5R, 0603 Kemet C0603C105K4PACTU 8
5 C4, C19 CAP, CERM, 10uF, 10V,
+/-10%, X5R, 0805 Kemet C0805C106K8PACTU 2
6 D1 Lumex 1594540000 1
7 L1 FB, 120 ohm, 500mA,
0603 Murata BLM18AG121SN1D 1
8OSCin, RFout,
VccVCO Connector, SMT, End launch SMA 50 ohm Emerson Network Power 142-0701-851 3
9R3, R20, R21,
R23, R55 RES, 0 ohm, 5%, 0.1W, 0603 Vishay-Dale CRCW06030000Z0EA 5
10 R1, R2, R4, R6, R7, R9, R10, R12,
R56 RES, 10.0 ohm, 1%,
0.1W, 0603 Vishay-Dale CRCW060310R0FKEA 9
11 R27, R29, R31 RES, 18 ohm, 5%, 0.1W,
0603 Vishay-Dale CRCW060318R0JNEA 3
12 R14 RES, 51 ohm, 5%, 0.1W,
0603 Vishay-Dale CRCW060351R0JNEA 1
13 R43 RES, 270 ohm, 5%,
0.1W, 0603 Vishay-Dale CRCW0603270RJNEA 1
14 R24, C21 RES, 1k ohm, 5%, 0.1W,
0603 Vishay-Dale CRCW060310K0JNEA 1
15 R32, R34, R35,
R36, R39 RES, 15k ohm, 5%, 0.1W, 0603 Vishay-Dale CRCW060315K0JNEA 5
16 R33, R37, R42,
R47 RES, 27k ohm, 5%, 0.1W, 0603 Vishay-Dale CRCW060327K0JNEA 4
17 S1,S2, S3, S4 0.375" Standoff Voltrex SPCS-6 4
18 U3
Ultra Low Noise, 150mA
Linear Regulator for
RF/Analog Circuits
Requires No Bypass
Capacitor, 6-pin LLP
Texas Instruments LP5900SDX-3.3 1
19 U5 Low Noise, RRO Op Amp
with CMOS Input Texas Instruments LM6211MF 1
20 U7 Fairchild BSS138 1
21 uWire FCI 52601-G10-8LF 1
22
S1, TP_Ftest/LD,
TP_OSCout,
TP_TRIGGER,
TP_VtuneIF,
TP_VtuneRF
Open Open None 6
23 FID1, FID2, FID3 Fiducial mark. There is
nothing to buy or mount. N/A N/A 3

Bill of Materials www.ti.com
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Table 5. Additional LMX2485E-EVM Specific Components
ITEM DESIGNATOR DESCRIPTION MANUFACTURER PART NUMBER QUANTITY
24 U1 LMX2485E Texas Instruments 1
25 U2 VCO Crystek CVCO55CL-0060-
0110 1
26 C1_RF CAP, CERM, 0.01uF,
100V, +/-5%, X7R, 0603 Kemet C0603C103J1RACT U1
27 C2_RF CAP, CERM, 0.68uF,
10V, +/-10%, X5R, 0603 Kemet C0603C684K8PAC 1
28 C3_RF CAP, CERM, 0.015uF,
100V, +/-10%, X7R, 0603 Kemet C0603C153K1RAC TU 1
29 C4_RF CAP, CERM, 1000pF, 50V, +/-5%, C0G/NP0,
0603 Kemet C0603C102J5GAC 1
30 R2_RF RES, 180 ohm, 5%,
0.1W, 0603 Vishay-Dale CRCW0603180RJN EA 1
31 R3_RF RES, 220 ohm, 5%,
0.1W, 0603 Vishay-Dale CRCW0603220RJN EA 1
32 R4_RF RES, 3.3k ohm, 5%,
0.1W, 0603 Vishay-Dale CRCW06033K30JN EA 1
Table 6. Additional LMX2487E-EVM Specific Components
ITEM DESIGNATOR DESCRIPTION MANUFACTURER PARTNUMBER QUANTITY
24 U1 LMX2487E Texas Instruments 1
25 U2 Crystek CVCO55BH-4100-
4300 1
26 C1_RF CAP, CERM, 5600pF, 100V, +/-
5%, X7R, 0603 AVX 06031C562JAT2A 1
27 C2_RF CAP, CERM, 0.12uF, 10V, +/-
10%, X5R, 0603 MuRata GRM188R61A124K
A01D 1
28 C3_RF CAP, CERM, 220pF, 100V, +/-
10%, X7R, 0603 AVX 06031C221KAT2A 1
29 C4_RF CAP, CERM,
1000pF, 50V, +/-
5%, C0G/NP0,
0603 Kemet C0603C102J5GAC 1
30 R2_RF RES, 270 ohm,
5%, 0.1W, 0603 Vishay-Dale CRCW0603270RJN EA 1
31 R3_RF RES, 1.2k ohm,
5%, 0.1W, 0603 Vishay-Dale CRCW06031K20JN EA 1
32 R4_RF RES, 1.2k ohm,
5%, 0.1W, 0603 Vishay-Dale CRCW06031K20JN EA 1

www.ti.com Layers Stackup
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6 Layers Stackup
4-layer PCB Stackup includes:
• Top Layer for high-priority high-frequency signals (1 oz.)
• Rogers 4003 Dielectric, 16 mils
• RF Ground plane (1 oz.)
• FR4
• Power (PWR) Layer
• FR4, 23 mils
• Bottom Layer copper clad for thermal relief (1 oz.)
• Total board thickness is 62 mils
7 PCB Layouts
Figure 4. Layer #1 – Top

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Figure 5. Layer #2 – RF Ground Plane

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Figure 6. Layer #3 – Power

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Figure 7. Layer #3 – Bottom Layer

www.ti.com Typical Phase Noise Performance Plots
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8 Typical Phase Noise Performance Plots
8.1 LMX2485E Phase Noise Plots
Figure 8. Impact of CPG on Phase Noise

Typical Phase Noise Performance Plots www.ti.com
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Figure 9. LMX2485E Impact of Fractional Modulator Order

www.ti.com Typical Phase Noise Performance Plots
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Figure 10. LMK2485E Impact of Dithering

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8.2 LMX2487E Phase Noise Plots
Figure 11. LMX2487E Impact of CPG on Phase Noise

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Figure 12. LMX2487E Impact on Fractional Modulator

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Figure 13. LMX2487E Impact of Dithering