45MHz to 650MHz, Integrated IF

VCOs with Differential Output

10

______________________________________________________________________________________

MAX2608

REQUIRED INDUCTANCE vs. DESIRED VCO FIXED FREQUENCY

40.0

38.0

37.0

32.0

29.0

27.0

25.0

22.0

20.0

17.0

15.0

13.0

11.0

310 320 330 340 350 360 370 380 390 400 410 420

470

9.0

300

480

41.0

420 430 440 450 460

490 500

36.0

35.0

34.0

33.0

31.0

30.0

28.0

26.0

24.0

23.0

21.0

19.0

18.0

16.0

14.0

12.0

10.0

EFFECTIVE INDUCTANCE

FROM IND TO GND

INDUCTOR VALUE

MOUNTED ON EV KIT

MEASUREMENT CONDITIONS

VCC = 2.75V, TA = 25°C,

RLOAD = 100Ω||50Ω (100Ω RESISTIVE PULL-UP PARALLELED WITH 50Ω

VNA IMPEDANCE), UNUSED OUTPUT TERMINATED IN 50

Ω,

PCB PARASITIC SHUNT CAPACITANCE (IND TO GND) = 0.45pF

THE INDUCTANCE LISTED IS THE PRECISE NOMINAL INDUCTANCE VALUE

REQUIRED FROM IND TO GND IN ORDER TO GUARANTEE THE VCO

CAN TUNE TO THE DESIRED FIXED FREQUENCY, OVER ALL OPERATING

CONDITIONS AND WORST-CASE COMPONENT

VALUES (

±2% INDUCTOR AND IC PROCESS VARIATION).

Figure 4. MAX2608 Required Inductance vs. Desired VCO Fixed Frequency