LMK03200EVAL National Semiconductor, LMK03200EVAL Datasheet - Page 16

• Manufacturer Part Number: LMK03200EVAL
• Description: BOARD EVALUATION LMK03200
• Manufacturer: National Semiconductor

Specifications of LMK03200EVAL

• Main Purpose: Timing, Clock Conditioner
• Embedded: No
• Utilized Ic / Part: LMK03200
• Primary Attributes: 3 LVDS & 5 LVPECL Outputs, Integrated PLL & VCO
• Secondary Attributes: 3.15 V ~ 3.45 V Supply
• Silicon Manufacturer: National
• Silicon Core Number: LMK03200
• Kit Application Type: Clock & Timing
• Application Sub Type: Precision Clock Conditioner
• Kit Contents: Board, Cable
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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1.10 DIGITAL LOCK DETECT
The PLL digital lock detect circuitry compares the difference
between the phase of the inputs of the phase detector to a
RC generated delay of ε. To indicate a locked state the phase
error must be less than the ε RC delay for 5 consecutive ref-
erence cycles. Once in lock, the RC delay is changed to
approximately δ. To indicate an out of lock state, the phase
error must become greater δ. The values of ε and δ are shown
in the table below:
To utilize the digital lock detect feature, PLL_MUX must be
programmed for "Digital Lock Detect (Active High)" or "Digital
Lock Detect (Active Low)." When one of these modes is pro-
grammed the state of the LD pin will be set high or low as
determined by the description above as shown in
When the device is in power down mode and the LD pin is
programmed for a digital lock detect function, LD will show a
"no lock detected" condition which is low or high given active
high or active low circuitry respectively.
The accuracy of this circuit degrades at higher comparison
frequencies. To compensate for this, the DIV4 word should
be set to one if the comparison frequency exceeds 20 MHz.
The function of this word is to divide the comparison frequen-
cy presented to the lock detect circuit by 4.
10 ns
ε
20 ns
δ
Figure
3.
16
1.11 CLKout DELAYS
Each individual clock output includes a delay adjustment.
Clock output delay registers (CLKoutX_DLY) support a 150
ps step size and range from 0 to 2250 ps of total delay.
FIGURE 3. Digital Lock Detect Flowchart
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