National Semiconductor LMX2531LQ2820E Operating Instructions Manual Download Page 1

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LMX2531LQ2820E

Evaluation Board Operating Instructions

National Semiconductor Corporation

Timing Devices Business Group

10333 North Meridian

Suite 400

Indianapolis, IN 46290

LMX25312820EVAL Instructions Rev 6.24.2009

Summary of Contents for LMX2531LQ2820E

Page 1: ...Q2820E Evaluation Board Operating Instructions National Semiconductor Corporation Timing Devices Business Group 10333 North Meridian Suite 400 Indianapolis IN 46290 LMX25312820EVAL Instructions Rev 6...

Page 2: ...VCO PHASE NOISE INTERNAL DIVIDE BY 2 DISABLED 7 FREE RUNNING VCO PHASE NOISE INTERNAL DIVIDE BY 2 ENABLED 8 FRACTIONAL SPURS INTERNAL DIVIDE BY 2 DISABLED 9 FRACTIONAL SPURS INTERNAL DIVIDE BY 2 ENAB...

Page 3: ...the OSCin pin Typically the 10 MHz output from the back of the RF test equipment is a good source Signal generators tend to be very noisy and should be used with caution If a signal generator is used...

Page 4: ...tion with the board Ensure the Green LEDs are lit on the USB board Ensure there are no conflicts with other USB devices and reinstall the board Part responds to programming but does not lock to the co...

Page 5: ...ing 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 t...

Page 6: ...0 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 2820 25 MHz Internal Divide by 2 Disabled DIV2 0 Output Frequency 1410 125 MHz Internal Divide...

Page 7: ...s 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 EN_PLLLDO2 EN_DIGLDO and EN_OSC bits The equipment needs to be able t...

Page 8: ...the EN_PLL EN_PLLLDO1 EN_PLLLDO2 EN_DIGLDO and EN_OSC 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...

Page 9: ...low a multiple of the crystal frequency The 67 5 dBc fractional spur at 250 kHz offset is at a worst case frequency of 2820 25 MHz The 71 8 dBc sub fractional spur at 125 kHz offset is also visible Wo...

Page 10: ...requency of 1355 125 MHz The 82 2 dBc sub fractional spur at 125 kHz offset is also visible The 72 6 dBc fractional spur at 250 kHz offset is at a worst case frequency of 1410 125 MHz The 56 7 dBc sub...

Page 11: ...I O N S Integer Spurs Internal Divide by 2 Disabled The integer spur at 10 MHz offset at an Fout frequency of 2710 MHz is 83 5 dBc The integer spur at 10 MHz offset at an Fout frequency of 2820 MHz is...

Page 12: ...I O N S Integer Spurs Internal Divide by 2 Enabled The integer spur at 10 MHz offset at an Fout frequency of 1355 MHz is 82 6 dBc The integer spur at 10 MHz offset at an Fout frequency of 1410 MHz is...

Page 13: ...29 8 dBc ORDER 4th Order Modulator Fractional numerator 500 Fractional denominator 1 000 000 The In band fractional spur at 5 kHz offset at an Fout frequency of 2820 005 MHz is 33 7 dBc ORDER 4th Ord...

Page 14: ...l numerator 500 Fractional denominator 1 000 000 The In band fractional spur at 5 kHz offset at an Fout frequency of 1410 0025 MHz is 41 8 dBc See inter modulation spur note on next page ORDER 4th Ord...

Page 15: ...025 MHz 1410 MHz 10 MHz 141 which is a multiple of the FPD 1410 0025 MHz is the divided output frequency Therefore a spur will occur at 2 5 kHz offset 1410 0025 1410 MHz If the frequency was set to 14...

Page 16: ...2 0 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 Select Device CodeLoader runs many devices When CodeLoader is first started it is necessary to select...

Page 17: ...ode can be recalled easily from the menu This restores bit settings and frequencies but not the Port Setup information For the CodeLoader program the default reference oscillator used for these instru...

Page 18: ...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 Bits Pins The Bits Pins tab displays many of the bits used to program the part Right mouse click any bit to view more informati...

Page 19: ...Counter Phase Detector Frequency N Counter and Charge Pump Gain should be set to provide the desired output frequency with an optimized loop filter The desired VCO frequency may also be entered direc...

Page 20: ...gisters 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 jus...

Page 21: ...I N G I N S T R U C T I O N S Port Setup 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 au...

Page 22: ...R7 R23 R22 Ftest LD C15 C22 R1 R9 TRIGGER GND 1 2 3 4 5 6 7 8 POWER C24 C14 C11 C19 C21 C23 NotethatAnyCom ponentw ithDesignator 100or Higher isontheBottomSideoftheBoard C10 Vcc Vcc R18 R24 R17 C105 C...

Page 23: ...R20 9 2 Panasonic P 22AHCT ND 603 10 0 1W Thick Film 0 22 R22 R23 10 2 Vishay CRCW06033R3JRT1 603 5 0 1W Thick Film 3 3 R1 R18 11 4 Vishay CRCW0603100JRT1 603 5 0 1W Thick Film 10 R2 R3 R4 R5 12 1 Vis...

Page 24: ...L M X 2 5 3 1 L Q 2 8 2 0 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 24...

Page 25: ...L M X 2 5 3 1 L Q 2 8 2 0 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 below top FR4 layer 25...

Page 26: ...L M X 2 5 3 1 L Q 2 8 2 0 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 26...

Page 27: ...L M X 2 5 3 1 L Q 2 8 2 0 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 27...

Page 28: ...L M X 2 5 3 1 L Q 2 8 2 0 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 28 Top Build Diagram...

Page 29: ...or 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...

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