LMX25311146EVAL National Semiconductor, LMX25311146EVAL Datasheet - Page 3

• Manufacturer Part Number: LMX25311146EVAL
• Description: BOARD EVAL FOR LMX25311146
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LMX25311146EVAL

• Main Purpose: Timing, Frequency Synthesizer
• Utilized Ic / Part: LMX2531LQ1146E
• Silicon Manufacturer: National
• Silicon Core Number: LMX2531
• Kit Application Type: Clock & Timing
• Application Sub Type: Frequency Synthesizer
• Kit Contents: Board, Cable, CD
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -
• Lead Free Status / Rohs Status: Supplier Unconfirmed

Loop Filter
Quick Setup
Crystal Frequency
Loop Bandwidth
Supply Voltage
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Phase Margin
Install the CodeLoader software which is available at www.national.com/timing.
Attach the parallel , or USB to parallel, port cable to the computer and the evaluation board.
Connect 3.0 volts to the Vcc connector
Connect the Fout connector to a spectrum analyzer or phase noise analyzer
Connect a clean 10 MHz source to 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.
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
It is recommended to ensure proper communication with the device
When using the lower frequency band with divide by 2 enabled (DIV2=1), be aware that the
frequency programmed to the VCO is actually twice the output frequency of the device
because the VCO frequency is being divided by 2.
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Select the proper part from the menu as Select Part->PLL+VCO->LMX2531LQ1146E
Select the proper mode from the Mode menu
Load the part by pressing Ctrl+L or selecting Keyboard Controls->Load Device from
the menu
Click the REG_RST bit on the bits/pins page and observe the current go to 0 mA
Unclick the REG_RST bit AND press Ctrl+L. The current should be approximately
35 mA
If device does not respond to this, consult the troubleshooting section
L M X 2 5 3 1 L Q 1 1 4 6 E
3.0 Volts
10 MHz
61.4
7.9
If a signal generator is used, the signal generator phase noise
Vtune
CPout
E V A L U A T I O N
Output Frequency
20 KΩ
VCO Gain
3
Fcomp
Kφ
100 pF
20 KΩ
B O A R D
O P E R A T I N G
1106 - 1184 MHz (DIV2=0)
VCO
100 pF
553 - 592 MHz (DIV2=1)
2.5-5.5 MHz/Volt
1440 uA (16X)
10 MHz
I N S T R U C T I O N S