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L M X 2 5 3 1 L Q 1 3 1 2 E   E V A L U A T I O N   B O A R D   O P E R A T I N G   I N S T R U C T I O N S  

 
 
 

Troubleshooting 

Problem Corrective 

Actions 

Softw

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e do

es

 no

t co

mmu

nica

te 

with th

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alua

tio

n

 boa

rds 

All Modes 

• 

Ensure a valid signal is presented to the 

OSCin

 connector.  If a signal 

generator is used, ensure the RF is ON.

 

• 

Consult the CodeLoader instructions for more detailed information on 
communication issues

 

LPT Mode (Uses Parallel Port Cable) 

• 

Ensure CodeLoader is set to LPT mode on the Port Setup tab.

 

• 

Ensure the proper port number is selected (LPT1, LPT2, LPT3).  CodeLoader 
does NOT automatically detect this.

 

• 

Ensure the LPT cable is securely connected to the computer and board.

 

• 

Exit and Restart CodeLoader.

 

• 

Ensure the parallel port is in the correct mode 

 

o 

Windows often requires Administrative access to write to the parallel 
port. 

o 

Ensure that the parallel port is set to “Enabled” in windows device 
manager. 

o 

A reboot upon installation of CodeLoader is sometimes necessary to 
get the parallel port to work. 

o 

Standard mode is the most reliable.  This can be set in the BIOS mode 
of the computer as “Normal”, “Output Only”, or “AT”. 

USB Mode (Uses USB to Parallel Port Converter) 

• 

On the menu, select USB->Version to verify communication with the board.

 

• 

Ensure the Green LEDs are lit on the USB board.

 

• 

Ensure there is no conflicts with other USB devices and reinstall the board.

 

Part r

es

p

o

nds to

 

prog

ra

mmin

g, bu

t 

doe

s no

t lo

ck

 to 

the

 

corr

ec

t fre

q

u

enc

y 

• 

Ensure there is a valid signal presented to the 

OSCin

 connector.  If a signal 

generator is used, ensure that the RF is set to ON.

 

• 

If using the lower frequency band (DIV2=1), the VCO frequency in CodeLoader 
should be twice the frequency at the Fout pin.

 

• 

Ensure the VCO FREQUENCY CAL bits on the Bits/Pins tab are correct. 

• 

Ensure the loop filter is optimized if the charge pump current, phase detector 
frequency, or loop filter values have been changed from their original settings.  
Ensure the integrated loop filter components on CodeLoader are set to their 
proper settings. 

C

l

n

o

os

e-

in

 ph

ase 

ise

 is

 w

o

rs

e 

th

an e

valu

atio

n

 

boa

rd 

instru

ctio

ns sho

w

 

• 

Ensure the signal presented to the OSCin connector is clean.  Try another 
source, or if it is a signal generator, try using a higher frequency and dividing it 
down to the required phase detector frequency.

 

• 

Ensure the OSCin signal and cable provides sufficient power level.

 

• 

If the phase detector frequency or charge pump current is lowered from its’ 
original setting, the in-band phase noise can be degraded even if the loop filter 
is re-designed for the same loop bandwidth.  If the loop bandwidth is 
decreased, in-band phase noise can be degraded.

 

F

ar-

ou

t Ph

ase 

n

o

ise

 is

 

w

o

rs

e 

th

an ev

alu

atio

n

 

boa

rd 

instru

ctio

ns sho

w

 

• 

Ensure the measurement equipment noise floor is not limiting the 
measurement.  For spectrum analyzers, the noise floor at a particular setting 
can be measured by removing the RF input signal.

 

• 

If the settings are changed from what the board was designed for, ensure the 
delta-sigma modulator is not increasing the far-out noise.  To determine this, 
tune to an integer channel and set the ORDER bit to “Reset Modulator”.  The 
far out phase noise should not decrease.  If a decrease occurs, try a loop filter 
with more attenuation or select a lower order delta-sigma modulator.

 

 

 

 

4

Содержание LMX2531LQ1515E

Страница 1: ...X2531LQ1515E Evaluation Board Operating Instructions National Semiconductor Corporation Timing Devices Business Group 10333 North Meridian Suite 400 Indianapolis IN 46290 LMX2531LQ1515EFPEB Rev 4 02 2008 ...

Страница 2: ...DIVIDE BY 2 DISABLED 6 FREE RUNNING VCO PHASE NOISE INTERNAL DIVIDE BY 2 ENABLED 7 FRACTIONAL SPURS INTERNAL DIVIDE BY 2 DISABLED 8 FRACTIONAL SPURS INTERNAL DIVIDE BY 2 ENABLED 9 INTEGER SPURS INTERNAL DIVIDE BY 2 DISABLED 10 INTEGER SPURS INTERNAL DIVIDE BY 2 ENABLED 11 CODELOADER SETTINGS 12 SCHEMATIC 17 BILL OF MATERIALS 18 TOP LAYER 19 MID LAYER 1 GROUND PLANE 20 MID LAYER 2 POWER 21 BOTTOM L...

Страница 3: ...tors tend to be very noisy and should be used with caution If a signal generator is used the signal generator phase noise contribution can be reduced by setting the signal to 80 MHz and dividing this down to a phase detector frequency of 10 MHz Set up the CodeLoader software o Select the proper part from the menu as Select Part PLL VCO LMX2531LQ1515E o Select the proper mode from the Mode menu o L...

Страница 4: ...is used ensure that the RF is set to ON If using the lower frequency band DIV2 1 the VCO frequency in CodeLoader should be twice the frequency at the Fout pin Ensure the VCO FREQUENCY CAL bits on the Bits Pins tab are correct Ensure the loop filter is optimized if the charge pump current phase detector frequency or loop filter values have been changed from their original settings Ensure the integr...

Страница 5: ... 3 1 2 E E V A L U A T I O N B O A R D O P E R A T I N G I N S T R U C T I O N S Phase Noise Output Frequency 1515 MHz Internal Divide by 2 Disabled DIV2 0 Output Frequency 757 5 MHz Internal Divide by 2 Enabled DIV2 1 5 ...

Страница 6: ...of the VCO In order to take these plots the E5052 phase nose analyzer was used The method was to lock the PLL to the proper frequency then disable the EN_PLL EN_PLLLDO1 and EN_PLLLDO2 bits The equipment needs to be able to track the VCO phase noise to measure in this way and one can not let the VCO drift too far off in frequency If this kind of equipment is not available the VCO phase noise can al...

Страница 7: ...was to lock the PLL to the proper frequency then disable the EN_PLL EN_PLLLDO1 and EN_PLLLDO2 bits The equipment needs to be able to track the VCO phase noise to measure in this way and one can not let the VCO drift too far off in frequency If this kind of equipment is not available the VCO phase noise can also be measured by making a very narrow loop bandwidth filter When divide by 2 is enabled t...

Страница 8: ...Spur at 250 kHz offset at a worst case frequency of 1450 25 MHz is 72 7 dBc Worst case channels occur at exactly one channel spacing above or below a multiple of the crystal frequency Fractional Spur at 250 kHz offset at a worst case frequency of 1520 25 MHz is 69 4 dBc Fractional Spur at 250 kHz offset at a worst case frequency of 1570 25 MHz is 77 7 dBc 8 ...

Страница 9: ... MHz is 80 4 dBc Since this mode uses the divide by 2 mode the channel spacing here is actually 125 kHz The spur at 125 kHz could be eliminated by doubling the channel spacing before the divider Spur at 250 kHz offset for a frequency of 615 125 MHz is 85 7 dBc Spur at 250 kHz offset for a frequency of 630 125 MHz is 84 5 dBc The sub fractional spur at 125 kHz offset of 79 dBc is also visible 9 ...

Страница 10: ... T R U C T I O N S Integer Spurs Internal Divide by 2 Disabled Spur at 10 MHz offset for a frequency of 1450 MHz is 83 7 dBc Spur at 10 MHz offset for a frequency of 1520 MHz is below the spectrum analyzer noise floor Spur at 10 MHz offset for a frequency of 1580 MHz is 92 0 dBc 10 ...

Страница 11: ...rs Internal Divide by 2 Enabled Spur at 10 MHz offset for a frequency of 725 MHz is below the spectrum analyzer noise floor Spur at 10 MHz offset for a frequency of 707 5 MHz is below the spectrum analyzer noise floor Spur at 10 MHz offset for a frequency of 790 MHz is below the spectrum analyzer noise floor 11 ...

Страница 12: ... 1 2 E E V A L U A T I O N B O A R D O P E R A T I N G I N S T R U C T I O N S CodeLoader Settings CodeLoader is designed to run many devices When CodeLoader is first started it is necessary to select the correct device 12 ...

Страница 13: ...menu This restores bit settings and frequencies but not the Port Setup information The default reference oscillator used for these instructions was 10 MHz but there is an alternate mode for a 61 44 MHz oscillator as well If the bits become scrambled their original state may be recalled by choosing the appropriate mode If the internal divide by 2 DIV2 is enabled the VCO frequency will not change 13...

Страница 14: ...y bit to view more information about what this does When the DIV2 bit is enabled the frequency from the part will be half of that shown on the PLL VCO tab The frequency on the PLL VCO tab does not reflect this because the divide by 2 is actually after the VCO Also be sure to load the device Ctrl L after changing this bit to allow the VCO to calibrate for optimal phase noise performance 14 ...

Страница 15: ...N S The Registers tab shows the literal bits that are being sent to the part These are the registers every time the PLL is loaded by using the menu command or Ctrl L R5 INIT1 and R5 INIT 2 are just the R5 register being used to properly initialize the part So a single Ctrl L will load the part 15 ...

Страница 16: ... S T R U C T I O N S The port setup tells CodeLoader what information goes where If this is wrong the part will not program Although LPT1 is usually correct CodeLoader does NOT automatically detect the correct port On some laptops it may be LPT3 Manual verification is required 16 ...

Страница 17: ... C1 R2 C12 C2 VccVCO VccDIG VccPLL VccBUF R3 C3 C17 R4 C9 C4 R5 C5 OSCin VccVCO VccPLL VccBUF C13 C18 C20 R7 R23 R22 Ftest LD C15 C22 R1 R9 TRIGGE R GND 1 2 3 4 5 6 7 8 POWER C24 C14 C11 C19 C21 C23 Notethat AnyComponent w ithDesignator 100or Higheris ontheBottomSideof theBoard C10 VccDIG 1 NC 2 GND 3 NC 4 NC 5 VregBUF 6 NC 7 DATA 8 CLK 9 LE 10 CE 11 NC 12 NC 13 NC 14 NC 15 VccVCO 16 Vr egVCO 17 V...

Страница 18: ...Ω R1 R18 10 4 Vishay CRCW060310R0JNEA 603 5 0 1W Thick Film 10Ω R2 R3 R4 R5 11 1 Vishay CRCW060351R0JNEA 603 5 0 1W Thick Film 51Ω R6 12 1 Vishay CRCW060310K0JNEA 603 5 0 1W Thick Film 1KΩ R2_LF 13 4 Vishay CRCW060310K0JNEA 603 5 0 1W Thick Film 10KΩ R9 R11 R13 R15 14 4 Vishay CRCW060312K0JNEA 603 5 0 1W Thick Film 12KΩ R10 R12 R14 R16 15 1 Comm Con Connectors HTSM3203 8G2LF 2X4 n a n a Metal Plas...

Страница 19: ...L M X 2 5 3 1 L Q 1 3 1 2 E E V A L U A T I O N B O A R D O P E R A T I N G I N S T R U C T I O N S Top Layer 19 ...

Страница 20: ...L M X 2 5 3 1 L Q 1 3 1 2 E E V A L U A T I O N B O A R D O P E R A T I N G I N S T R U C T I O N S Mid Layer 1 Ground Plane 15 Mils Down FR4 20 ...

Страница 21: ...L M X 2 5 3 1 L Q 1 3 1 2 E E V A L U A T I O N B O A R D O P E R A T I N G I N S T R U C T I O N S Mid Layer 2 Power 21 ...

Страница 22: ...L M X 2 5 3 1 L Q 1 3 1 2 E E V A L U A T I O N B O A R D O P E R A T I N G I N S T R U C T I O N S Bottom Layer Signal Note Total Board Thickness 61 mils 22 ...

Страница 23: ...L M X 2 5 3 1 L Q 1 3 1 2 E E V A L U A T I O N B O A R D O P E R A T I N G I N S T R U C T I O N S Top Build Diagram 23 ...

Страница 24: ...for use in safety critical applications such as life support where a failure of the TI product would reasonably be expected to cause severe personal injury or death unless officers of the parties have executed an agreement specifically governing such use Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications and acknowledge and agre...

Страница 25: ...Mouser Electronics Authorized Distributor Click to View Pricing Inventory Delivery Lifecycle Information Texas Instruments LMX25311515EVAL LMX25311515EVAL NOPB ...

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