Analog Frequency Multiplier

PL660 and PL663 XO Families

47745 Fremont Blvd., Fremont, California 94538 TEL (510) 492-0990, FAX (510) 492-0991

www.phaselink.com

Rev. 3/20/07 Page 7

120 MHz AFM Tuning: Using the “AFM Tuning Assistant” find the PL660-0x in the L2X worksheet. Enter the

Cinternal value found next to it into cell B21. In cell B24 enter the closest standard inductor value (see CoilCraft

0603CS series for example) to achieve the closest peak frequency to 60 MHz. Repeat the same procedure for

L4X at 120 MHz.

Results: L2X = 180 nH, L4X = 82 nH.

320 MHz AFM tuning: Repeat the previous procedure for L2X at 120 MHz and L4X at 320 MHz.

Results: L2X = 24 nH, L4X = 10 nH.

Proceed and assemble the test units.

Measuring 120 MHz L2X: Connect the RF generator and scope probe as shown in Figure 6. While power is

applied to the PCB, set the generator output to +12 dBm and the frequency to 30 MHz. Since this is the 2x port,

the scope will show 60 MHz with ~ 3V pk-pk amplitude. Vary the generator above and below 30 MHz until the

amplitude on the scope is maximum and record the generator frequency. For example peak recorded at 29.8x2 or

59.6 MHz.

Measuring 320 MHz L2X: Connect the RF generator and scope probe as shown in Figure 6. While power is

applied to the PCB, set the generator output to +12 dBm and the frequency to 80 MHz. Since this is the 2x port the

scope will show 160 MHz with ~ 3V pk-pk amplitude. Vary the generator above and below 80 MHz until the

amplitude on the scope is maximum and record the generator frequency. For example peak recorded at 78.0 x 2 =

156 MHz

In the AFM Tuning Assistant, add the scope’s probe capacitance to the Cstray cell. For our example 0.5 pF + 1.0

pF = 1.5 pF. With L2X at 24 nH adjust LWB1 (cell B23) until the peak frequency reads 156 MHz. Next replace the

L2X value with 180 nH and see if it peaks at 59.6 MHz. If it does not, adjust the Cstray until 59.4 MHz is achieved.

Again enter 24 nH for L2X and fine tune LWB1 for 156 MHz.

Results: LWB1 = 1.6 nH, Cstray = 2.9 pF-0.5 pF = 2.4 pF (subtract scope probe stray)

Repeat the same steps for the L4X: Set the generator to 80 MHz. The 82 nH peaks at 118 MHz and the 10 nH

peaks at 304 MHz.

Results: LWB1 = 1.8 nH, Cstray = 2.5 pF-0.5 pF = 2.0 pF (subtract scope probe stray)

Internal Capacitor Selection by Device

Device Number

Cinternal (pF)

2X

4X

PL660-0X

34.125

16.500

PL663-0X

46.500

PL663-1X

14.625

PL663-2X

14.625