MAX2608EUT+T ,45MHz to 650MHz, Integrated IF VCOs with Differential OutputELECTRICAL CHARACTERISTICS(V = +2.7V to +5.5V, V = 0.4V to 2.4V, T = -40°C to +85°C, unless otherwi ..
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t Microprocessor Interface V
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MAX260AENG ,Microprocessor Programmable Universal Active FiltersELECTRICAL CHARACTERISTICS
N' = +5V, V' = -5V, CLK, = CLKB = 1 5V 350kHz for the MAX260 and 1.5M ..
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MAX5940AESA ,IEEE 802.3af PD Interface Controller For Power-Over-EthernetFeaturesThe MAX5940A/MAX5940B provide complete interface Fully Integrated IEEE 802.3af-Compliant ..
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MAX2606EUT+T-MAX2607EUT+T-MAX2608EUT+T
45MHz to 650MHz, Integrated IF VCOs with Differential Output
AVAILABLE
EVALUATION KIT AVAILABLE
General DescriptionThe MAX2605–MAX2609 are compact, high-performance
intermediate-frequency (IF) voltage-controlled oscillators
(VCOs) designed specifically for demanding portable
wireless communication systems. They combine monolith-
ic construction with low-noise, low-power operation in a
tiny 6-pin SOT23 package.
These low-noise VCOs feature an on-chip varactor and
feedback capacitors that eliminate the need for external
tuning elements, making the MAX2605–MAX2609 ideal
for portable systems. Only an external inductor is
required to set the oscillation frequency. In addition, an
integrated differential output buffer is provided for dri-
ving a mixer or prescaler. The buffer output is capable
of supplying up to -8dBm (differential) with a simple
power match. It also provides isolation from load
impedance variations.
The MAX2605–MAX2609 operate from a single +2.7V to
+5.5V supply and offer low current consumption. These IF
oscillators can cover the 45MHz to 650MHz frequency
range.
ApplicationsCellular and PCS Mobile Phones
2.4GHz ISM Band
902MHz to 928MHz ISM Band
Land Mobile Radio
GPS Receivers
General-Purpose IF Oscillators
FeaturesSmall Size Integrated Varactor for TuningLow Phase NoiseWide Application Frequency RangeDifferential or Single-Ended OutputsSingle +2.7V to +5.5V SupplyUltra-Small SOT23-6 PackageOn-Chip Temperature-Stable BiasLow-Current Operation
45MHz to 650MHz, Integrated IF
VCOs with Differential OutputGND
OUT-TUNEOUT+VCC
IND
MAX2605
MAX2606
MAX2607
MAX2608
MAX2609
SOT23-6TOP VIEW
Pin Configuration/
Functional Diagram
Ordering Information
PARTMAX2605
MAX2606
MAX2607150 to 300
70 to 150
45 to 70
FREQUENCY
RANGE
(MHz)
SUPPLY
CURRENT
(mA)MAX2608300 to 5002.7
PHASE
NOISE
(dBc/Hz)MAX2609500 to 6503.6-93
Selector GuideAABE6 SOT23-6-40°C to +85°C
MAX2608EUT-TAABD
AABC
AABB
TOP
MARK6 SOT23-6
6 SOT23-6
6 SOT23-6
PIN-
PACKAGETEMP. RANGE-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
MAX2607EUT-T
MAX2606EUT-T
MAX2605EUT-T
PARTAABF6 SOT23-6-40°C to +85°C
MAX2609EUT-TMAX2605–MAX2609
45MHz to 650MHz, Integrated IF
VCOs with Differential Output
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS(VCC= +2.7V to +5.5V, VTUNE= 0.4V to 2.4V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VCC= +2.75V,
VTUNE= 1.5V, and TA= +25°C.) (Note1)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
VCCto GND..............................................................-0.3V to +6V
IND to GND................................................-0.6V to (VCC+ 0.3V)
TUNE to GND.............................................-0.3V to (VCC+ 0.3V)
OUT+, OUT- to GND..................................-0.3V to (VCC+ 0.6V)
Continuous Power Dissipation (TA= +85°C)
6-Pin SOT23 (derate 8.7mW/°C above +70°C)...........696mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
MAX2609TA= -40°C to +85°C = +25°C
DC Output Current (Note 3)0.51.01.5OUT+ plus OUT-= -40°C to +85°C = +25°C= -40°C to +85°C = +25°C= -40°C to +85°C = +25°C= -40°C to +85°C = +25°C
PARAMETERMINTYPMAXUNITSSupply Current (Note 2)
TUNE Input Current0.03nA
Supply Voltage2.75.5V1.92.6
CONDITIONS
MAX2607
MAX2606
MAX2608
MAX2605
MAX2605–MAX2609
45MHz to 650MHz, Integrated IF
VCOs with Differential Output
AC ELECTRICAL CHARACTERISTICS(MAX2605–MAX2609 EV kits, VCC= +2.7V to +5.5V, VTUNE= 0.4V to 2.4V, TA= -40°C to +85°C, unless otherwise noted. Typical val-
ues are at VCC= +2.75V, VTUNE= 1.5V, and TA= +25°C.) (Note 1)
MAX2609, QL≥40
Peak Tuning Gain14.5%/VVTUNE= 0.4V to 0.6V step (Note 6)= +25°C-5.0+3.8
MAX2609
MAX2608, QL≥40
MAX2607, QL≥35
MAX2606, QL≥35
MAX2605, QL≥35
-107dBc/Hz
Phase Noise (Note 8)
fOFFSET= 100kHz
-4.7+3.6TA= +25°C= +25°C= +25°C= +25°C
PARAMETERMINTYPMAXUNITSGuaranteed Frequency Limits
(relative to nominal) (Note 5)
-4.1+3.2
-4.4+3.4
-4.6+3.6
Oscillator Nominal Frequency
Range (Note 4)70150
CONDITIONS
MAX2606
MAX2605
MAX2608
MAX2607
MAX2608
MAX2605
MAX2606
MAX2607
Single-Ended Output Power
(Note 7) -10dBm= -40°C to +85°C= -40°C to +85°C= -40°C to +85°C= -40°C to +85°C= -40°C to +85°C
-2.25+2.25
-2.5+2.5
-2.75+2.75
-2.8+2.8
-3.0+3.0
MAX2609
MHz
MAX2605–MAX2609
45MHz to 650MHz, Integrated IF
VCOs with Differential Output
AC ELECTRICAL CHARACTERISTICS (continued)(MAX2605–MAX2609 EV kits, VCC= +2.7V to +5.5V, VTUNE= 0.4V to 2.4V, TA= -40°C to +85°C, unless otherwise noted. Typical val-
ues are at VCC= +2.75V, VTUNE= 1.5V, and TA= +25°C.) (Note 1)
Note 1:Production tested at TA= +25°C. Maximum and minimum over temperature limits are guaranteed by design and
characterization.
Note 2:Supply current is measured while the part is oscillating and inductor Q ≥QMIN. For MAX2605/MAX2606/MAX2607, QMIN= 35;
for MAX2608/MAX2609, QMIN= 40.
Note 3:The DC output current is the total available output signal current.
Note 4:Application range of the part is achieved using external inductance as specified in Figures 1-5 and shown in Figure 6. The inter-
nal varactors support center frequencies of 45MHz to 650MHz. The center frequency is defined by the value of the external
inductor element, LF. The application frequency limits are guaranteed by design and characterization.
Note 5:The guaranteed (tested) limits ƒMINand ƒMAXare measured at VTUNE= 0.4V and VTUNE= 2.4V, respectively. Passing
requirements are: ƒ ≤ƒMINat VTUNE= 0.4 and ƒ ≥ƒMAXat VTUNE= 2.4V. The nominal frequency of oscillation is defined by
the inductor.
Note 6:Describes peak tuning gain, which occurs at VTUNE= 0.4V.
Note 7:Measurement at OUT+ or OUT- matched for optimum power transfer into 50Ωload near the center of the operating frequency
range.
Note 8:The phase-noise specifications listed apply to the typical operating circuit shown in Figure 6. Apply over the entire operating
frequency range of the MAX2605–MAX2609.
Note 9:Supply pushing is measured with VCCstepped from +2.7V to +3.2V.
SUPPLY CURRENT
vs. TEMPERATURE
MAX2605/9-01
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
MAX2609
MAX2605
MAX2606MAX2607MAX2608
TUNE INPUT LEAKAGE CURRENT
vs. TEMPERATURE
MAX2605/9-02
TEMPERATURE (°C)
LEAKAGE CURRENT (nA)1.00.51.52.02.53.0
MAX2605
VCO TUNING CURVEMAX2605/9-03
VTUNE (V)
FREQUENCY (MHz)
Typical Operating Characteristics(MAX260_ EV kit, VCC= +2.75V, VTUNE= 1.4V, TA = +25°C, unless otherwise noted.)
dBcEven-Order Harmonics-30Differential, RL= 50Ωeach side
PARAMETERMINTYPMAXUNITS
CONDITIONSMAX2605
120MAX2606
480MAX2608
220MAX2607Supply Pushing (Note 9)
kHz/V
MAX2609
MAX2605–MAX2609
45MHz to 650MHz, Integrated IF
VCOs with Differential OutputMAX2606
VCO TUNING CURVE
MAX2605/9-04
VTUNE (V)
FREQUENCY (MHz)
MAX2607
VCO TUNING CURVE
MAX2605/9-05
VTUNE (V)
FREQUENCY (MHz)
MAX2608
VCO TUNING CURVE
MAX2605/9-06
VTUNE (V)
FREQUENCY (MHz)
MAX2609
VCO TUNING CURVE
MAX2605/9-07
VTUNE (V)
FREQUENCY (MHz)
4fo5fo2fo3fofo6fo7fo
MAX2605/9-08
FREQUENCY
(dB)
OUTPUT SPECTRUM
NAMEFUNCTIONINDTuning Inductor Port. Connect an inductor from IND to GND to set VCO center frequency (see Oscillation
Frequency).GNDGround. Connect to the ground plane with a low-inductance path.
PINTUNEVoltage-Control Input for Frequency Tuning. Input voltage range from +0.4V to +2.4V.OUT-High-Impedance Open-Collector Output. An external pull-up resistor or inductor to VCCis required. Output
power is dependent on external load impedance. OUT- is complementary to OUT+. OUT+High-Impedance Open-Collector Output. An external pull-up resistor or inductor to VCCis required. Output
power is dependent on external load impedance. OUT+ is complementary to OUT-.VCCSupply Voltage Connection. Connect an external bypass capacitor to ground for low noise and low spuri-
ous-output content. See Layout Issuesfor more details.
Pin Descriptionypical Operating Characteristics (continued)(MAX260_ EV kit, VCC= +2.75V, VTUNE= 1.4V, TA = +25°C, unless otherwise noted.)
MAX2605–MAX2609
45MHz to 650MHz, Integrated IF
VCOs with Differential Output
Detailed DescriptionThe MAX2605–MAX2609 are low-noise VCOs designed
for fixed/single-frequency IF applications. The core
oscillator circuit is based on the well-known Colpitts
topology. The varactor and feedback capacitors are
integrated on-chip so that only an external inductor is
required to establish the frequency of oscillation and
produce a properly operating VCO. The tuning range,
biasing, startup, etc., are all managed within the IC. This
highly integrated design dramatically simplifies the
parts’ application.
The tuning range is wide enough so that, with the use
of ±2% tolerance inductors, no board-level adjustments
to the oscillation frequency are necessary. Once the
correct inductor value is chosen, the VCO is guaran-
teed always to tune to the desired operating frequency.
In addition, with the use of inductors of moderate Q (35
to 40), the VCO achieves excellent phase-noise perfor-
mance.
Applications Information
Desired Oscillation FrequencyThe desired VCO operating frequency is set by the
value of the external inductance, LF. Figures 1–5 show
the inductance value LFrequired to achieve the desired
oscillation frequency. The inductor value can be taken
directly from these figures. Inductance must be select-
ed accurately to ensure proper operation over all con-
ditions.
Inductor Implementation The inductance value required for the desired operat-
ing frequency may not necessarily coincide with a stan-
dard-value SMT inductor, which typically increases size
in ~1.2x steps. In such cases, the inductance must be
constructed from two inductors, LF1and LF2, in order to
achieve the desired inductance value. Choose LF1to
be a standard-value inductor with a value just less than
that required for LF. Choose LF2to be a standard-value
inductor with a value just less than (LF- LF1). LF1
should adhere to the minimum Q requirements, but LF2
may be implemented as a lower-cost, lower-Q, thin-film
SMT inductor. Its lower Q has only a small impact on
the overall Q of the total inductance because it is <20%
of the total inductance. However, the overall Q of LF1
and LF2must be greater than the minimum inductor Q
(Table 1).
It is also permissible to use PC board traces to provide
a small amount of inductance, thereby adjusting the
total inductance value. On the MAX2608/MAX2609, the
inductance values for LF2are sometimes more exactly
implemented as a PC board trace (shorted to GND),
rather than an SMT inductor. When designing LF with
two inductors, use the simple model in Figure 7 to cal-
culate XLand LEQ.
The LFin Figures 1–5 represents an equivalent induc-
tance as seen by pin 1 (IND). The equivalent induc-
tance corresponds to the inductive reactance
connected to IND at the desired oscillation frequency
(fNOMINAL).
LEQ= XL/ (2πfNOMINAL) as seen in Figure 8
Design LEQ= LFat the desired fNOMINAL. The
MAX2605–MAX2609 are designed to tolerate approxi-
mately 0.5pF of external parasitic capacitance at IND.
This parasitic capacitance arises from the pad capaci-
tance at the device pin and pads for the inductor.
Additional shunt capacitance is not recommended
because it degrades the tuning range.
Bypass Capacitor on TUNEThe MAX2605–MAX2609’s oscillator design uses a vari-
ant of the Colpitts topology, where DC bias for the var-
actor is applied via a DC voltage on TUNE and a
ground connection through the external inductor LF.
TUNE must also have a high-frequency AC ground for
Table 1. External Inductor LFRangeTable 2. CBYPASSValues3.9 ≤LF≤15500 to 650MAX2609
MIN
INDUCTOR 10 ≤LF≤47300 to 500MAX2608
39 ≤LF≤180
150 ≤LF≤820
680 ≤LF≤2200
INDUCTANCE
RANGE
(nH)
FREQUENCY
RANGE
(MHz)45 to 70
70 to 150
150 to 300MAX2607
MAX2606
MAX2605
PART≥39 pFMAX2609
≥100 pFMAX2608
≥330 pF
≥680 pF
≥820 pF
CBYPASSMAX2607
MAX2606
MAX2605
DEVICEMAX2605–MAX2609
45MHz to 650MHz, Integrated IF
VCOs with Differential Output
MAX2605
REQUIRED INDUCTANCE vs. DESIRED VCO FIXED FREQUENCYREQUIRED INDUCTANCE (nH)474951535557596163656769
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 50Ω,
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).
DESIRED VCO FIXED FREQUENCY (MHz)
Figure 1. MAX2605 Required Inductance vs. Desired VCO Fixed Frequency
MAX2605–MAX2609
45MHz to 650MHz, Integrated IF
VCOs with Differential Output
MAX2606
REQUIRED INDUCTANCE vs. DESIRED VCO FIXED FREQUENCYREQUIRED INDUCTANCE (nH)80859095100105110115120125130135
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 50Ω,
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).
DESIRED VCO FIXED FREQUENCY (MHz)
Figure 2. MAX2606 Required Inductance vs. Desired VCO Fixed Frequency
MAX2605–MAX2609
