UNKNOWN 3256)

VCO Tank Design for the MAX2310

© Sep 30, 2002, Maxim Integrated Products, Inc.

Abstract: This application note presents various voltage-controlled oscillator (VCO) designs for popular IF frequencies of 85MHz, 190MHz, and 210MHz. These designs reduce the number of iterations required for optimized results. Analysis can be accomplished with a simple spreadsheet program.

Additional Information:

Introduction

This application note presents various voltage-controlled oscillator (VCO) designs for popular IF frequencies of 85MHz, 190MHz, and 210MHz. These designs reduce the number of iterations required for optimized results. Analysis can be accomplished with a simple spreadsheet program.

VCO Design

Figure 2 shows the differential tank circuit used for the MAX2310 IF VCO. For analysis purposes, the tank circuit must be reduced to an equivalent simplified model. Figure 1 depicts the basic VCO model. The frequency of oscillation can be characterized by EQN1:

EQN1

fosc = frequency of oscillation
L = inductance of the coil in the tank circuit
Cint = internal capacitance of the MAX2310 tank port
Ct = total equivalent capacitance of the tank circuit

Figure 1. Basic VCO model.
Figure 1. Basic VCO model.

Rn = equivalent negative resistance of the MAX2310 tank port
Cint = internal capacitance of the MAX2310 tank port
Ct = total equivalent capacitance of the tank circuit
L = inductance of the coil in the tank circuit

Figure 2. The MAX2310 tank circuit.
Figure 2. The MAX2310 tank circuit.

Inductor L resonates with the total equivalent capacitance of the tank and the internal capacitance of the oscillator (Ct+Cint) (see Figure 1). Ccoup provides DC block and couples the variable capacitance of the varactor diodes to the tank circuit. Ccent is used to center the tank's oscillation frequency to a nominal value. It is not required but adds a degree of freedom by allowing one to fine-tune resonance between inductor values. Resistors (R) provide reverse-bias voltage to the varactor diodes via the tune voltage line (Vtune). Their value should be chosen large enough so as not to affect loaded-tank Q but small enough so that 4kTBR noise is negligible. The resistors' noise voltage gets modulated by KVCO, producing phase noise. Capacitance Cv is the variable tuning component in the tank. The capacitance of varactor diode (Cv) is a function of reverse-bias voltage (see Appendix A for the varactor model). Vtune is the tuning voltage from a phase-locked loop (PLL).

Figure 3 shows the lumped Cstray VCO model. Parasitic capacitance and inductance plague every RF circuit. In order to predict the frequency of oscillation, the parasitic elements must be taken into account. The circuit in Figure 3 lumps the parasitic elements in one capacitor called Cstray. The frequency of oscillation can be characterized by EQN2:

EQN2

L = inductance of the coil in the tank circuit
Cint = internal capacitance of the MAX2310 tank port
Ccent = tank capacitor used to center oscillation frequency
Cstray = lumped stray capacitance
Ccoup = tank capacitor used to couple the varactor to the tank
Cv = net variable capacitance of the varactor diode (including series inductance)
Cvp = varactor-pad capacitance

Figure 3. Lumped Cstray model.
Figure 3. Lumped Cstray model.

Figure 4 depicts the detailed VCO model. It takes into account the capacitance of the pads but does not include the effects of series inductance for simplicity. Cstray is defined as:

EQN3

CL = capacitance of the inductor
CLP = capacitance of the inductor pads
CDIFF = capacitance due to parallel traces

Figure 4. Detailed VCO model.
Figure 4. Detailed VCO model.

Rn = equivalent negative resistance of the MAX2310 tank port
Cint = internal capacitance of the MAX2310 tank port
LT = inductance of series trace to the inductor tank circuit
CDIFF = capacitance due to parallel traces
L = inductance of the coil in the tank circuit
CL = capacitance of the inductor
CLP = capacitance of inductor pads
Ccent = tank capacitor used to center oscillation frequency
Ccoup = tank capacitor used to couple the varactor to the tank
Cvar = variable capacitance of the varactor diode
Cvp = varactor-pad capacitance
LS = series inductance of the varactor
R = resistance of the varactor reverse-bias resistors

To simplify analysis, inductance LT is ignored in this design. The effects of LT are more pronounced at higher frequencies. To mathematically model the shift in frequency due to LT with the spreadsheets that follow, the value of CDIFF can be increased appropriately. Minimize inductance LT to prevent undesired series resonance. This can be accomplished by making the traces short.

Tuning Gain

Tuning gain (Kvco) must be minimized for best closed-loop phase noise. Resistors in the loop filter as well as the resistors "R" (Figure 2) will produce broadband noise. Broadband thermal noise ( ) will modulate the VCO by Kvco, which is measured in MHz/V. There are two ways to minimize Kvco. One is to minimize the frequency range over which the VCO must tune. The second way is to maximize the tuning voltage available. To minimize the frequency range over which the VCO must tune, tight tolerance components must be used, as will be shown. To maximize tuning voltage, a charge pump with a large compliance range is needed. This is usually accomplished by using a larger Vcc. The compliance range for the MAX2310 is 0.5V to Vcc-0.5V. In battery-powered applications, the compliance range is usually fixed by battery voltage or a regulator.

Basic Concept for Trimless Design

VCO design for manufacturability with real-world components will require an error budget analysis. In order to design a VCO to oscillate at a fixed frequency (fosc), the tolerance of the components must be taken into consideration. Tuning gain (Kvco) must be designed into the VCO to account for these component tolerances. The tighter the component tolerance, the smaller the possible tuning gain, and the lower the closed-loop phase noise. For worst-case error budget design, we will look at three VCO models:
  1. Maximum-value components (EQN5)
  2. Nominal tank, all components perfect (EQN2)
  3. Minimum-value components (EQN4)
All three VCO models must cover the desired nominal frequency. Figure 5 shows visually how the three designs must converge to provide a manufacturable design solution. Observation of EQN1 and Figure 5 reveal that minimum-value components will shift the oscillation frequency higher and that maximum-value components will shift the oscillation frequency lower.

Figure 5. Worst-case and nominal-tank centering.
Figure 5. Worst-case and nominal-tank centering.

Minimum tuning range must be used in order to design a tank with the best closed-loop phase noise. Therefore, the nominal tank should be designed to cover the center frequency with overlap to take into account device tolerance. The worst-case high-tune tank and worst-case low-tune tank should tune just to the edge of the desired oscillation frequency. EQN2 can be modified by component tolerance to produce a worst-case high-tune tank EQN4 and a worst-case low-tune tank EQN5.

EQN4

EQN5

TL = % tolerance of the inductor (L)
TCINT = % tolerance of the capacitor (CINT)
TCCENT = % tolerance of the capacitor (CCENT)
TCCOUP = % tolerance of the capacitor (CCOUP)
TCV = % tolerance of the varactor capacitance (CV)

EQN4 and EQN5 assume that the strays do not have a tolerance.

General Design Procedure

Step 1

Estimate or measure pad capacitance and other strays. The stray capacitance on the MAX2310 Rev C EV kit has been measured with a Boonton Model 72BD capacitance meter. CLP = 1.13pF, CVP = 0.82pF, CDIFF = 0.036pF.

Step 2

Determine the value for capacitance Cint. This can be found in the MAX2310/MAX2312/MAX2314/MAX2316 data sheet on Page 5. Typical operating characteristic TANKH PORT 1/S11 vs. FREQUENCY shows the equivalent parallel RC values for several popular LO frequencies. Appendix B includes tables of Cint versus frequency for the high- and low-band tank ports. Keep in mind that the LO frequency is twice the IF frequency.

Example:

For an IF frequency of 210MHz (high-band tank), the LO will operate at 420MHz. From Appendix B, Table 5, Cint = 0.959pF.

Step 3

Choose an inductor. A good starting point is using the geometric mean. This will be an iterative process.
EQN6

This equation assumes L in (nH) and C in (pF) (1x10-9 x 1x10-12 = 1x10-21). L = 11.98nH for a fosc = 420MHz. This implies a total tank capacitance C = 11.98pF. An appropriate initial choice for an inductor would be 12nH Coilcraft 0805CS-12NXGBC 2% tolerance.

When choosing an inductor with finite step sizes, the following formula EQN6.1 will be useful. The total product LC should be constant for a fixed oscillation frequency fosc.

EQN6.1

LC = 143.5 for a fosc = 420MHz. The trial-and-error process with the spreadsheet in Table 3 yielded an inductor value of 18nH 2% with a total tank capacitance of 7.9221pF. The LC product for the tank in Figure 8 is 142.59, close enough to the desired LC product of 143.5. One can see this is a useful relationship to have on hand. For best phase noise, choose a high-Q inductor like the Coilcraft 0805CS series. Alternatively, a micro-strip inductor can be used if the tolerance and Q can be controlled reasonably.

Step 4

Determine the PLL compliance range. This is the range over which the VCO tuning voltage (Vtune) will be designed to work. For the MAX2310, the compliance range is 0.5V to Vcc-0.5V. For a Vcc = 2.7V, this would set the compliance range to 0.5 to 2.2V. The charge-pump output will set this limit. The voltage swing on the tank is 1Vp-p centered at 1.6VDC. Even with large values for Ccoup, the varactor diodes will not be forward-biased. This is a condition to be avoided, as the diode will rectify the AC signal on the tank pins, producing undesirable spurious response and loss of lock in a closed-loop PLL.

Step 5

Choose a varactor. Look for a varactor with good tolerance over your specified compliance range. Keep the series resistance small. For a figure of merit, check that the self-resonant frequency of the varactor is above the desired operating point. Look at the Cv(2.5V)/Cv(0.5V) ratio at your compliance-range voltage. If the coupling capacitors Ccoup were chosen large, then the maximum tuning range can be calculated using EQN2. Smaller values of capacitor Ccoup will reduce this effective frequency tuning range. When choosing a varactor, it should have a tolerance specified at your given compliance-range mid and end points. Select a hyperabrupt varactor such as the Alpha SMV1763-079 for linear tuning response. Take the value for total tank capacitance, and use that for Cjo of the varactor. Remember, Ccoup will reduce the net capacitance coupled to the tank.

Step 6

Pick a value for Ccoup. Large values of Ccoup will increase tuning range by coupling more of the varactor into the tank at the expense of decreasing tank-loaded Q. Smaller values of Ccoup will increase the effective Q of the coupled varactor and loaded Q of the tank at the expense of reducing tuning range. Typically this will be chosen as small as possible, while still getting the desired tuning range. Another benefit of choosing Ccoup small is that it reduces the voltage swing across the varactor diode. This will help thwart forward-biasing the varactor.

Step 7

Pick a value for Ccent, usually around 2pF or greater for tolerance purposes. Use Ccent to center the VCO's nominal frequency.

Step 8

Iterate with the spreadsheet.

MAX2310 VCO Tank Designs for IF Frequencies of 85MHz, 190MHz, and 210MHz

The following spreadsheets show designs for several popular IF frequencies for the MAX2310. Keep in mind that the LO oscillates at twice the desired IF frequency.

Figure 6. 85MHz low-band IF tank schematic.
Figure 6. 85MHz low-band IF tank schematic.

Table 1. 85MHz Low-Band IF Tank Design
  Light grey indicates calculated values.

  Darker grey indicates user input.

MAX2310 Low-Band Tank Design and Tuning Range
Total Tank Capacitance vs. V tune
V tune  Total C Ct
(Nominal)
Ct
(Low)
Ct
(High)
0.5V Ct high 14.1766pF 13.3590pF 14.9459pF
1.375V Ct mid 12.8267pF 11.7445pF 13.7620pF
2.2V Ct low 11.4646pF 10.3049pF 12.4534pF
 
Tank Components
Tolerance
C coup
18pF
0.9pF
5%
C cent
5.6pF
0.1pF
2%
C stray
0.70pF
   
L
68nH
2.00%
 
C int
0.902pF
10.00%
 
 
Parasitics and Pads (C stray)
Due to Q
C L
0.1pF
Ind. pad
C Lp
1.13pF
Due to ||
C diff
0.036pF
Var. pad
C vp
0.82pF
 
Varactor Specs
Alpha SMV1255-003
Cjo
82pF
Varactor Tolerance
Vj
17V
0.5V
19.00%
M
14
1.5V
29.00%
Cp
0pF
2.5V
35.00%
Rs
 Reactance
Ls
1.7nH
X Ls
1.82
Freq
170.00MHz
 
 
Nominal Varactor
X c
Net Cap
Cv high
54.64697pF
-17.1319
61.12581pF
Cv mid
27.60043pF
-33.92
29.16154pF
Cv low
14.92387pF
-62.7321
15.36874pF
 
Negative Tol Varactor (Low Capacitance)
Cv high
44.26404pF
-21.1505
48.42117pF
Cv mid
19.59631pF
-47.7746
20.37056pF
Cv low
9.700518pF
-96.5109
9.886531pF
 
Positive Tol Varactor (High Capacitance)
Cv high
65.02989pF
-14.3965
74.41601pF
Cv mid
35.60456pF
-26.2945
38.24572pF
Cv low
20.14723pF
-46.4682
20.96654pF
 
  Nominal LO
(Nom) Range
Low Tol IF
(High) Range
Nominal IF
(Nom) Range
High Tol IF
(Low) Range
F low
162.10MHz
84.34MHz
81.05MHz
78.16MHz
F mid
170.42MHz
89.95MHz
85.21MHz
81.45MHz
F high
180.25MHz
96.03MHz
90.13MHz
85.62MHz
BW
18.16MHz
11.69MHz
9.08MHz
7.46MHz
% BW
10.65%
12.99%
10.65%
9.16%
 
Nominal IF Frequency
85.00MHz
 
Design Constraints
Condition for bold number
<IF
=IF
> IF
Delta
0.66
-0.21
0.62
Test
pass
pass
pass
Raise or lower cent freq by
-0.21
MHz
Inc or dec BW
-1.28
MHz
Cent adj for min BW
84.98
MHz
 
K vco
10.68MHz/V

Figure 7. 190MHz high-band IF tank schematic.
Figure 7. 190MHz high-band IF tank schematic.

Table 2. 190MHz High-Band IF Tank Design
  Light grey indicates calculated values.

  Darker grey indicates user input.

MAX2310 High-Band Tank Design and Tuning Range
Total Tank Capacitance vs. V tune
V tune
Total C Ct
(Nominal)
Ct
(Low)
Ct
(High)
0.5V
Ct high 10.4968pF 10.0249pF 10.9126pF
1.375V
Ct mid 9.6292pF 8.8913pF 10.2124pF
2.2V
Ct low 8.6762pF 7.7872pF 9.3717pF
 
Tank Components
Tolerance
C coup
12pF
0.1pF
1%
C cent
3.4pF
0.1pF
3%
C stray
0.70pF
   
L
18nH
2.00%
 
C int
0.954pF
10.00%
 
 
Parasitics and Pads (C stray)
Due to Q
C L
0.01pF
Ind. pad
C Lp
1.13pF
Due to ||
C diff
0.036pF
Var. pad
C vp
0.82pF
 
Varactor Specs
Alpha SMV1255-003
Cjo
82pF
Varactor Tolerance
Vj
17V
0.5V
19.00%
M
14
1.5V
29.00%
Cp
0pF
2.5V
35.00%
Rs
 Reactance
Ls
1.7nH
X Ls
4.06
Freq
380.00MHz
 
 
Nominal Varactor
X c
Net Cap
Cv high
54.64697pF
-7.66426
116.1695pF
Cv mid
27.60043pF
-15.1747
37.67876pF
Cv low
14.92387pF
-28.0643
17.44727pF
 
Negative Tol Varactor (Low Capacitance)
Cv high
44.26404pF
-9.46205
77.51615pF
Cv mid
19.59631pF
-21.3728
24.19031pF
Cv low
9.700518pF
-43.1759
10.70708pF
 
Positive Tol Varactor (High Capacitance)
Cv high
65.02989pF
-6.44056
175.8588pF
Cv mid
35.60456pF
-11.7633
54.36221pF
Cv low
20.14723pF
-20.7884
25.03539pF
 
  Nominal LO
(Nom) Range
Low Tol IF
(High) Range
Nominal IF
(Nom) Range
High Tol IF
(Low) Range
F low
366.15MHz
189.23MHz
183.07MHz
177.78MHz
F mid
382.29MHz
200.94MHz
191.14MHz
183.78MHz 
F high
402.74MHz
214.71MHz
201.37MHz
191.84MHz
BW
36.59MHz
25.47MHz
18.29MHz
14.06MHz
% BW
9.57%
12.68%
9.57%
7.65% 
 
Nominal IF Frequency
190MHz
 
Design Constraints
Condition for bold number 
< IF
= IF
> IF
Delta
0.77
-1.14
1.84 
Test
pass
pass
pass 
Raise or lower cent freq by  
-1.14
MHz 
Inc or dec BW  
-2.61
MHz 
Cent adj for min BW
190.54
MHz 
 
K vco
21.52MHz/V

Figure 8. 210MHz high-band IF tank schematic.
Figure 8. 210MHz high-band IF tank schematic.

Table 3. 210MHz High-Band IF Tank Design
  Light grey indicates calculated values.

  Darker grey indicates user input.

MAX2310 High-Band Tank Design and Tuning Range
Total Tank Capacitance vs. V tune
V tune 
Total C Ct
(Nominal)
Ct
(Low)
Ct (High)
0.5V
Ct high 8.8304pF 8.1465pF 9.4877pF
1.35V
Ct mid 7.9221pF 7.0421pF 8.6970pF
2.2V
Ct low 6.9334pF 5.9607pF 7.7653pF
 
Tank Components
Tolerance
C coup
12pF
0.6pF
5%
C cent
1.6pF
0.1pF
6%
C stray
0.70pF
   
L
18nH
2.00%
 
C int
0.959pF
10.00%
 
 
Parasitics and Pads (C stray)
Due to Q
C L
0.1pF
Ind. pad
C Lp
1.13pF
Due to ||
C diff
0.036pF
Var. pad
C vp
0.82pF
 
Varactor Specs
Alpha SMV1255-003
Cjo
82pF
Varactor Tolerance
Vj
17V
0.5V
19.00%
M
14
1.5V
29.00%
Cp
0pF
2.5V
35.00%
Rs
 Reactance
Ls
1.7nH
X Ls
4.49 
Freq
420.00MHz
 
 
Nominal Varactor
X c
Net Cap
Cv high
54.64697pF
-6.93433
154.787pF
Cv mid
27.60043pF
-13.7295
40.99616pF 
Cv low
14.92387pF
-25.3916
18.12647pF
 
Negative Tol Varactor (Low Capacitance)
Cv high
44.26404pF
-8.56091
92.99806pF
Cv mid
19.59631pF
-19.3373
25.51591pF
Cv low
9.700518pF
-39.0639
10.95908pF 
 
Positive Tol Varactor (High Capacitance)
Cv high
65.02989pF
-5.82717
282.5852pF
Cv mid
35.60456pF
-10.643
61.54791pF
Cv low
20.14723pF
-18.8086
26.45795pF
 
  Nominal LO
(Nom) Range
Low Tol IF
(High) Range
Nominal IF
(Nom) Range
High Tol IF
(Low) Range
F low
399.20MHz
209.92MHz
199.60MHz
190.67MHz
F mid
421.47MHz
225.78MHz
210.73MHz
199.14MHz
F high
450.52MHz
245.41MHz
225.26MHz
210.75MHz
BW
51.31MHz
35.49MHz
25.66MHz
20.09MHz
% BW
12.18%
15.72%
12.18%
10.09%
 
Nominal IF Frequency
210MHz
 
Design Constraints
condition for bold number
< IF
= IF
> IF
Delta
0.08
-0.73
0.75
Test
pass
pass
pass 
Raise or lower cent freq by  
-0.73
MHz
Inc or dec BW
-0.83
MHz
Cent adj for min BW
210.34
MHz
 
K vco
30.18MHz/V   

Figure 9. High-Q 210MHz high-band IF tank schematic.
Figure 9. High-Q 210MHz high-band IF tank schematic.

Table 4. High-Q 210MHz High-Band IF Tank Design
  Light grey indicates calculated values.

  Darker grey indicates user input.

MAX2310 High-Band Tank Design and Tuning Range
Total Tank Capacitance vs. V tune
V tune 
Total C Ct
(Nominal)
Ct
(Low)
Ct (High)
0.5V
Ct high 5.8856 5.5289 6.2425
1.375V
Ct mid 5.2487 4.9113 5.5858
2.2V
Ct low 4.8371 4.5156 5.1581
 
Tank Components
C coup
15pF
0.75pF
5%
C cent
1.6pF
0.1pF
6%
C stray
0.77pF
   
L
27
2.00%
 
C int
0.959
10.00%
 
 
Parasitics and Pads (C stray)
Due to Q
C L
0.17pF
Ind. pad
C Lp
1.13pF
Due to ||
C diff
0.036pF
Var. pad
C vp
0.82pF
 
Varactor Specs
Alpha SMV1763-079
Cjo
8.2pF
Varactor Tolerance
Vj
15V
0.5V
7.50%
M
9.5
1.5V
9.50%
Cp
0.67pF
2.5V
11.50%
Rs
0.5Ω
 Reactance
Ls
0.8nH
X Ls
2.11
Freq
420.00MHz
 
 
Nominal Varactor
X c
Net Cap
Cv high
6.67523pF
-56.7681
6.933064pF
Cv mid
4.23417pF
-89.4958
4.336464pF 
Cv low
2.904398pF
-130.471
2.952167pF
 
Negative Tol Varactor (Low Capacitance)
Cv high
6.174588pF
-61.3709
6.39456pF
Cv mid
3.831924pF
-98.8904
3.915514pF
Cv low
2.570392pF
-147.425
2.607736pF 
 
Positive Tol Varactor (High Capacitance)
Cv high
7.175873pF
-52.8076
7.474698pF
Cv mid
4.636416pF
-81.7313
4.759352pF
Cv low
3.238404pF
-117.015
3.297904pF
 
  Nominal LO
(Nom) Range
Low Tol IF
(High) Range
Nominal IF
(Nom) Range
High Tol IF
(Low) Range
F low
399.25MHz
208.05MHz
199.62MHz
191.92MHz
F mid
422.78MHz
220.75MHz
211.39MHz
202.89MHz
F high
440.40MHz
230.22MHz
220.20MHz
211.14MHz
BW
41.15MHz
22.16MHz
20.58MHz
19.21MHz
% BW
9.73%
10.04%
9.73%
9.47%
 
Nominal IF Frequency
210MHz
 
Design Constraints
Condition for bold number
< IF
= IF
> IF
Delta
1.95
-1.39
1.14
Test
pass
pass
pass 
Raise or lower cent freq by  
-1.39
MHz
Inc or dec BW
-3.08
MHz
Cent adj for min BW
209.60
MHz
 
K vco
24.21MHz/V   

Appendix A

Figure 10. Varactor model.
Figure 10. Varactor model.

Alpha Application Note AN1004 has additional information on varactor models. Varactor capacitance is defined in EQN7:

EQN7

Alpha SMV1255-003 Alpha SMV1763-079
Cjo = 82 pF Cjo = 8.2 pF
Vj =17 V Vj =15 V
M = 14 M = 9.5
Cp = 0 Cp = 0.67
Rs = 1Ω Rs = 0.5Ω
Ls = 1.7 nH Ls = 0.8 nH

The series inductance of the varactor is taken into account by backing out the inductive reactance and calculating a new effective capacitance Cv:
EQN8

Appendix B

Table 5. Cint vs. Frequency for the MAX2310 High-Band Tank
Frequency (MHz) Cint (pF) Frequency (MHz) (cont.) Cint (pF) (cont.)
100 0.708 360 0.949
110 0.759 370 0.955
120 0.800 380 0.954
130 0.809 390 0.954
140 0.839 400 0.954
150 0.822 410 0.955
160 0.860 420 0.959
170 0.869 430 0.956
180 0.880 440 0.959
190 0.905 450 0.964
200 0.917 460 0.962
210 0.920 470 0.963
220 0.926 480 0.963
230 0.924 490 0.960
240 0.928 500 0.964
250 0.935 510 0.965
260 0.932 520 0.968
270 0.931 530 0.966
280 0.933 540 0.968
290 0.927 550 0.967
300 0.930 560 0.974
310 0.933 570 0.977
320 0.943 580 0.976
330 0.944 590 0.984
340 0.945 600 0.982
350 0.956 - -

Figure 11. Cint vs. frequency for the MAX2310 high-band tank (sixth-order polynomial curve fit)
Figure 11. Cint vs. frequency for the MAX2310 high-band tank (sixth-order polynomial curve fit)

Table 6. Cint vs. Frequency for the MAX2310 Low-Band Tank
Frequency (MHz) Cint (pF) Frequency (MHz) (cont.) Cint (pF) (cont.)
100 0.550 360 1.001
110 0.649 370 0.982
120 0.701 380 0.992
130 0.764 390 1.001
140 0.762 400 0.985
150 0.851 410 0.980
160 0.838 420 0.986
170 0.902 430 0.992
180 0.876 440 0.994
190 0.907 450 1.001
200 0.913 460 1.003
210 0.919 470 1.007
220 0.945 480 0.992
230 0.952 490 1.010
240 0.965 500 1.004
250 0.951 510 1.011
260 0.954 520 1.022
270 0.974 530 1.019
280 0.980 540 1.044
290 0.973 550 1.026
300 0.982 560 1.041
310 0.970 570 1.038
320 0.982 580 1.032
330 0.991 590 1.036
340 0.993 600 1.025
350 0.991 - -

Figure 12. C<sub>int</sub> vs. frequency for the MAX2310 low-band tank (sixth-order polynomial curve fit).
Figure 12. Cint vs. frequency for the MAX2310 low-band tank (sixth-order polynomial curve fit).

References

  1. Chris O'Connor, Develop Trimless Voltage-Controlled Oscillators, Microwaves and RF, July1999.
  2. Wes Hayward, Radio Frequency Design, Chapter 7.
  3. Krauss, Bostian, Raab, Solid State Radio Engineering, Chapters 2, 3, 5.
  4. Alpha Industries Application Note AN1004.
  5. Coilcraft, RF Inductors Catalog, March 1998, p.131.
  6. Maxim, MAX2310/MAX2312/MAX2314/MAX2316 Data Sheet, Rev 0.
  7. Maxim, MAX2310/MAX2314 Evaluation Kit Data Sheet, Rev 0.
  8. Maxim, MAX2312/MAX2316 Evaluation Kit Data Sheet, Rev 0.


Related Parts
MAX2306 CDMA IF VGAおよびI/Q復調器、VCOおよび合成付 Free Samples  
MAX2308 CDMA IF VGAおよびI/Q復調器、VCOおよび合成付 Free Samples  
MAX2309 CDMA IF VGAおよびI/Q復調器、VCOおよび合成付 Free Samples  
MAX2310 VCOおよびシンセサイザ付き、CDMA IF VGAおよびI/Q復調器  
MAX2312 VCOおよびシンセサイザ付き、CDMA IF VGAおよびI/Q復調器  
MAX2314 VCOおよびシンセサイザ付き、CDMA IF VGAおよびI/Q復調器  
MAX2316 VCOおよびシンセサイザ付き、CDMA IF VGAおよびI/Q復調器  


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Unknown: Sep 30, 2002
UNKNOWN 3256), AN530, AN 530, APP530, Appnote530, Appnote 530