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19-1528; Rev 0; 8/99
ANUAL
N KIT M EET
ATIO
SH
EVALU
S DATA
OLLOW
F
Monolithic Voltage-Controlled Oscillators
General Description
Features
o
Fully Monolithic
o
Guaranteed Performance
o
Wide Choice of Frequencies
855MHz to 881MHz (MAX2622)
885MHz to 950MHz (MAX2623)
947MHz to 998MHz (MAX2624)
o
+2.7V to +3.3V Single-Supply Operation
o
Low-Current Shutdown Mode
o
Smaller than Modules (8-pin µMAX package)
MAX2622/MAX2623/MAX2624
The MAX2622/MAX2623/MAX2624 self-contained volt-
age-controlled oscillators (VCOs) combine an integrat-
ed oscillator and output buffer in a miniature 8-pin
µMAX package.
The inductor and varactor elements of the tank circuits
are integrated on-chip, greatly simplifying application of
the part. In addition, the center frequency of oscillation
and frequency span are factory preset to provide a
guaranteed frequency range versus control voltage. An
external tuning voltage controls the oscillation frequency.
The output signals are buffered by an amplifier stage
(easily matched to 50Ω), using only capacitors to pro-
vide higher output power and isolate the devices from
load impedance variations.
The MAX2622/MAX2623/MAX2624 operate from a
+2.7V to +3.3V supply voltage and require only 9mA of
supply current. In shutdown mode, the supply current is
reduced to 0.1µA.
Ordering Information
PART
MAX2622EUA
MAX2623EUA
MAX2624EUA*
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 µMAX
8 µMAX
8 µMAX
Applications
866MHz to 868MHz European ISM Band (MAX2622)
DECT 1/2 Frequency LO (MAX2623)
902MHz to 928MHz ISM Band, ±10.7MHz IF
(MAX2623)
902MHz to 928MHz ISM Band, 45MHz to 70MHz IF
(MAX2624)
Pin Configuration appears at end of data sheet
*Future
product—contact factory for availability.
Typical Operating Circuit
N.C.
GND
TUNE
TUNE
C
SERIES
OSCILLATOR
CORE
OUT
C
SHUNT
GND
V
CC
100pF
OUT TO MIXER/
SYNTHESIZER
SHDN
SHDN
MAX2622
MAX2623
MAX2624
BIAS
V
CC
V
CC
100pF
0.1µF
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Monolithic Voltage-Controlled Oscillators
MAX2622/MAX2623/MAX2624
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ..............................................................-0.3V to +6V
TUNE,
SHDN
to GND .................................-0.3V to (V
CC
+ 0.3V)
OUT to GND ...............................................-0.3V to (V
CC
+ 0.6V)
Continuous Power Dissipation (T
A
= +70°C)
8-pin µMAX (derate 5.7mW/°C above T
A
= +70°C)...457mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
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.
DC ELECTRICAL CHARACTERISTICS
(Typical
Operating Circuit,
V
CC
= +2.7V to +3.3V, V
TUNE
= 1.4V, V
SHDN
= 2V, OUT = unconnected, T
A
= -40°C to +85°C, unless
otherwise noted. Typical values are at V
CC
= +3V, T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage
Supply Current
Shutdown Supply Current
SHDN
Input Voltage Low
SHDN
Input Voltage High
SHDN
Input Current Low
SHDN
Input Current High
TUNE Input Current
V
SHDN
≤
0.6V
V
CC
= 3.3V
V
CC
= 2.7V
V
SHDN
= 0.6V, V
CC
= 3.3V
V
SHDN
= 2.0V, V
CC
= 3.3V
0.4V
≤
V
TUNE
2.4V
2.0
-0.5
-0.5
0.2
0.5
0.5
CONDITIONS
MIN
2.7
9
0.1
TYP
MAX
3.3
11.5
10
0.6
UNITS
V
mA
µA
V
V
µA
µA
nA
AC ELECTRICAL CHARACTERISTICS
(Typical
Operating Circuit,
V
CC
= +2.7V to +3.3V, V
TUNE
= 0.4V to 2.4V, V
SHDN
= 2V, T
A
= +25°C, unless otherwise noted. Typical
values measured at V
CC
= +3V.) (Note 1)
PARAMETER
Oscillator Frequency Range
CONDITIONS
MAX2622, V
TUNE
= 0.4V to 2.4V, T
A
= -40°C to +85°C
MAX2623, V
TUNE
= 0.4V to 2.4V, T
A
= -20°C to +75°C
MAX2624, V
TUNE
= 0.4V to 2.4V, T
A
= -40°C to +85°C
Phase Noise
Noise Floor
Tuning Gain (Note 2)
Output Power
Return Loss (Notes 3, 4)
Harmonics
Load Pulling
Supply Pushing
Note 1:
Note 2:
Note 3:
Note 4:
VSWR = 2:1, all phases
V
CC
stepped from 2.8V to 3.3V
V
TUNE
= 0.4V to 2.4V
V
TUNE
= 0.4V (Note 3)
f
OFF
= 100kHz
f
OFF
= 1MHz
MIN
855
885
947
-101
-119
-156
80
-8
-12
-30
0.5
200
110
TYP
MAX
881
950
998
dBc/Hz
dBm/Hz
MHz/V
dBm
dB
dBc
MHz
p-p
kHz/V
MHz
UNIT
Specifications are production tested at T
A
= +25°C. Limits over temperature are guaranteed by design and characterization.
Maximum tuning gain is measured at V
TUNE
= 0.4V with a 0.2V step to 0.6V. This represents the worst-case (highest) tuning gain.
Measurements taken on MAX262_ EV kit.
Return loss is optimized across all frequencies via external shunt/series capacitor matching.
2
_______________________________________________________________________________________
Monolithic Voltage-Controlled Oscillators
Typical Operating Characteristics
(V
CC
= +3.0V, V
TUNE
= 1.4V to 2.4V, V
SHDN
= 2V, T
A
= +25°C, unless otherwise noted.)
MAX2624
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX2622-01
MAX2624-02
MAX2622/MAX2623/MAX2624
SUPPLY CURRENT vs. TEMPERATURE
9.8
9.7
SUPPLY CURRENT (mA)
9.6
9.5
9.4
9.3
9.2
9.1
MAX2622
9.0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
0
-40
MAX2623
MAX2624
6
5
SUPPLY CURRENT (nA)
4
3
2
1
MAX2622
VCO TUNING CURVE
T
A
= -40°C
950
FREQUENCY (MHz)
T
A
= +25°C
900
T
A
= +85°C
850
MAX2622-03
1000
800
750
-20
0
20
40
60
80
0
0.5
1.0
1.5
V
TUNE
(V)
2.0
2.5
3.0
TEMPERATURE (°C)
MAX2623
VCO TUNING CURVE
MAX2623-04
MAX2624
VCO TUNING CURVE
MAX2624-05
PHASE NOISE
MAX2622-06
1050
T
A
= -40°C
1000
FREQUENCY (MHz)
T
A
= -20°C
950
T
A
= +25°C
900
T
A
= +85°C
850
T
A
= +75°C
1100
T
A
= -40°C
1050
T
A
= +25°C
1000
T
A
= +85°C
FREQUENCY (MHz)
-60
-70
PHASE NOISE (dBc)
-80
-90
-100
-110
950
900
-120
800
0
0.5
1.0
1.5
V
TUNE
(V)
2.0
2.5
3.0
850
0
0.5
1.0
1.5
V
TUNE
(V)
2.0
2.5
3.0
-130
10
100
FREQUENCY (kHz)
1000
NORMALIZED HARMONIC OUTPUT SPECTRUM
MAX2622-07
TUNE CURRENT vs. TEMPERATURE
1.8
1.6
1.4
CURRENT (nA)
1.2
1.0
0.8
0.6
0.4
0.2
0
MAX2624
-40
-20
0
20
40
60
80
MAX2622
MAX2623
MAX2622-08
2.0
∆
= 29.44dBc
∆
= 38.47dBc
OUTPUT POWER
f
O
2f
O
FREQUENCY
3f
O
TEMPERATURE (°C)
_______________________________________________________________________________________
3
Monolithic Voltage-Controlled Oscillators
MAX2622/MAX2623/MAX2624
Pin Description
PIN
NAME
N.C.
TUNE
GND
SHDN
V
CC
V
CC
OUT
GND
FUNCTION
Not connected. Do not make any connections to this pin.
Oscillator Frequency Tuning Voltage Input. High-impedance input with a voltage input range of 0.4V
(low frequency) to 2.4V (high frequency) adjustment.
Ground Connection for Oscillator and Biasing. Requires a low-inductance connection to the circuit board
ground plane.
Shutdown Logic Input. A high-impedance input logic level low disables the device and reduces supply current
to 0.1µA. A logic level high enables the device.
Output Buffer DC Supply Voltage Connection. Bypass with a 100pF capacitor to GND for best high-
frequency performance.
Bias and Oscillator DC Supply Voltage Connection. Bypass with a 100pF capacitor to GND for low noise
and low spurious content performance from the oscillator.
Buffered Oscillator Output. DC blocking capacitor required.
Ground Connection for Output Buffer. Requires a low-inductance connection to the circuit board
ground plane.
1
2
3
4
5
6
7
8
Detailed Description
Oscillator
The MAX2622/MAX2623/MAX2624 VCOs are imple-
mented as an LC oscillator topology, integrating all of
the tank components on-chip. This fully monolithic
approach provides an extremely easy-to-use VCO,
equivalent to a VCO module. The frequency is con-
trolled by a voltage applied to the TUNE pin, which is
internally connected to the varactor. The VCO core
uses a differential topology to provide a stable frequen-
cy versus supply voltage and improve the immunity to
load variations. In addition, there is a buffer amplifier
following the oscillator core to provide added isolation
from load variations and to boost the output power.
Applications Information
Output Matching
Although the output amplifier internally provides a par-
tial match to 50Ω, a simple external shunt series capac-
itor network is needed to optimize the match to 50Ω.
The off-chip capacitors are low-cost surface-mount
components. No inductors are required. The capacitors
are configured as shown in the
Typical Operating
Circuit
. The recommended values of C
SERIES
and
C
SHUNT
for the MAX2622/MAX2623/MAX2624 are
shown in Table 1. A typical application circuit is shown
in Figure 1.
Tuning Line
The tuning input is typically connected to the output of
the PLL loop filter. The loop filter is presumed to pro-
vide an appropriately low-impedance source. It may
incorporate an extra RC filter stage to reduce high-fre-
quency noise and spurious signals. Any excess noise
on the tuning input is directly translated into FM noise,
which can degrade the phase-noise performance of the
oscillator. Therefore, it is important to minimize the
noise introduced on the tuning input. A simple RC filter
with low corner frequency may be needed during test-
ing in order to filter the noise present on the voltage
source driving the tuning line.
Output Buffer
The oscillator signal from the core drives an output
buffer amplifier. The amplifier is constructed as a com-
mon-emitter stage with an integrated on-chip pull-up
inductor at the output. An external shunt-series capaci-
tor circuit optimizes the match to 50Ω. The output
amplifier has its own V
CC
and GND pins to minimize
load-pulling effects. The amplifier boosts the oscillator
signal to a level suitable for driving most RF mixers.
4
_______________________________________________________________________________________
Monolithic Voltage-Controlled Oscillators
MAX2622/MAX2623/MAX2624
N.C.
MAX2622
MAX2623
MAX2624
GND
FROM
SYNTHESIZER
TUNE
LOOP FILTER
OSCILLATOR
CORE
C
SERIES
OUT
C
SHUNT
100pF
V
CC
OUT TO MIXER/
SYNTHESIZER
GND
V
CC
1k
SHDN
100pF
SHDN
BIAS
V
CC
100pF
0.1µF
Figure 1. Typical Application Circuit
Table 1. Output Matching Components for
50Ω Match
DEVICE
MAX2622
MAX2623
MAX2624
C
SERIES
(pF)
2
1.5
1.3
C
SHUNT
(pF)
1
1
0.7
N.C.
1
TUNE
2
Pin Configuration
TOP VIEW
8
7
GND
OUT
V
CC
V
CC
Layout Issues
A properly designed PC board is essential to any
RF/microwave circuit/system. Always use controlled
impedance lines (microstrip, coplanar waveguide, etc.)
on high-frequency signals. Always place decoupling
capacitors as close to the V
CC
pins as possible. For
long V
CC
lines, it may be necessary to add additional
decoupling capacitors located further from the device.
Always provide a low-inductance path to ground. Keep
GND vias as close to the device as possible. Thermal
reliefs on GND pads are
not
recommended.
GND
3
MAX2622
MAX2623
MAX2624
6
5
SHDN
4
µMAX
_______________________________________________________________________________________
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