Datasheet

L M K 0 3 0 0 2 C

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

Appendix A: VCO Performance

The internal VCO performance is measured by using a narrow bandwidth loop filter. By default

the narrow loop bandwidth filter is stuffed as Loop Filter #2 in positions C1_AUX, C2_AUX,

C2p_AUX, and R2_AUX and has a loop bandwidth of 55 Hz.

See the Loop Filter section in Board Options for more detail about switching between the two

different loop filters.

Loop Filter #2

Phase Margin

58º

Kφ

φφ

100 uA

Loop Bandwidth

55 Hz

Fcomp

500 kHz

Crystal Frequency

16 MHz

Output Frequency

1566 to 1724 MHz

Supply Voltage

3.3 Volts

VCO Gain

13 MHz/Volt

VCO

820 nF

10 uF820

Ω

150 pF 110 pF

600 Ω

ΩΩ

Ω

200 Ω

ΩΩ

Ω

CPout

Charge Pump

C2R2

R3 R4

C3 C4

This loop filter is located on the top side of the PCB and is selected by placing a

0 ohm resistor on pad R5.

This loop filter has been designed with a very small loop bandwidth to minimize

the PLL from interacting with the noise of the VCO to permit a VCO phase noise

measurement.