Datasheet MAX2623EUA, MAX2622EUA Datasheet (Maxim)

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General Description

The MAX2622/MAX2623/MAX2624 self-contained volt­age-controlled oscillators (VCOs) combine an integrat­ed 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.

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)

Features

♦ Fully Monolithic
♦ Guaranteed Performance
♦ Wide Choice of Frequencies

855MHz to 881MHz (MAX2622)
885MHz to 950MHz (MAX2623)
947MHz to 998MHz (MAX2624)

♦ +2.7V to +3.3V Single-Supply Operation
♦ Low-Current Shutdown Mode
♦ Smaller than Modules (8-pin µMAX package)

MAX2622/MAX2623/MAX2624

Monolithic Voltage-Controlled Oscillators

________________________________________________________________

Maxim Integrated Products

1

19-1528; Rev 0; 8/99

PART
MAX2622EUA
MAX2623EUA
MAX2624EUA*

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

TEMP. RANGE PIN-PACKAGE

8 µMAX

8 µMAX

8 µMAX

EVALUATION KIT MANUAL

FOLLOWS DATA SHEET

Ordering Information

Typical Operating Circuit

Pin Configuration appears at end of data sheet

*

Future product—contact factory for availability.

N.C.

TUNE

SHDN

TUNE

GND

SHDN

OSCILLATOR

CORE

MAX2622
MAX2623
MAX2624

BIAS

GND

OUT

V

V

C

SERIES

C

SHUNT

CC

CC

100pF

100pF

OUT TO MIXER/
SYNTHESIZER

V

CC

0.1µF

MAX2622/MAX2623/MAX2624

Monolithic Voltage-Controlled Oscillators

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(

Typical Operating Circuit

, VCC= +2.7V to +3.3V, V

TUNE

= 1.4V, V

SHDN

= 2V, OUT = unconnected, TA= -40°C to +85°C, unless

otherwise noted. Typical values are at V

CC

= +3V, TA= +25°C.) (Note 1)

AC ELECTRICAL CHARACTERISTICS

(

Typical Operating Circuit,

VCC= +2.7V to +3.3V, V

TUNE

= 0.4V to 2.4V, V

SHDN

= 2V, TA= +25°C, unless otherwise noted. Typical

values measured at V

CC

= +3V.) (Note 1)

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.

Note 1: Specifications are production tested at T

A

= +25°C. Limits over temperature are guaranteed by design and characterization.

Note 2: 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.

Note 3: Measurements taken on MAX262_ EV kit.
Note 4: Return loss is optimized across all frequencies via external shunt/series capacitor matching.

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 (TA= +70°C)

8-pin µMAX (derate 5.7mW/°C above TA = +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

V

SHDN

≤ 0.6V

0.4V ≤ V

TUNE

2.4V

VCC= 3.3V

VCC= 2.7V

V

SHDN

= 0.6V, VCC= 3.3V

V

SHDN

= 2.0V, VCC= 3.3V

CONDITIONS

µA

0.1 10

Shutdown Supply Current

mA

9 11.5

V

2.7 3.3

Supply Voltage

Supply Current

nA

0.2

TUNE Input Current

V

0.6

SHDN Input Voltage Low

V

2.0

SHDN Input Voltage High

µA

-0.5 0.5

SHDN Input Current Low

µA

-0.5 0.5

SHDN Input Current High

UNITSMIN TYP MAXPARAMETER

f

OFF

= 100kHz

f

OFF

= 1MHz

dBc/Hz

-101

Phase Noise

-119

V

CC

stepped from 2.8V to 3.3V

VSWR = 2:1, all phases

V

TUNE

= 0.4V (Note 3)

CONDITIONS

885 950

kHz/V

200

Supply Pushing

MHz

p-p

0.5

MAX2623, V

TUNE

= 0.4V to 2.4V, TA= -20°C to +75°C

Load Pulling

dBc

-30

Harmonics

dB

-12

Return Loss (Notes 3, 4)

dBm/Hz

-156

Noise Floor

dBm

-8

Output Power

UNITMIN TYP MAXPARAMETER

MAX2622, V

TUNE

= 0.4V to 2.4V, TA= -40°C to +85°C

Oscillator Frequency Range MHz

855 881

V

TUNE

= 0.4V to 2.4V MHz/V

80 110

Tuning Gain (Note 2)

MAX2624, V

TUNE

= 0.4V to 2.4V, TA = -40°C to +85°C

947 998

MAX2622/MAX2623/MAX2624

Monolithic Voltage-Controlled Oscillators

_______________________________________________________________________________________

3

Typical Operating Characteristics

(VCC= +3.0V, V

TUNE

= 1.4V to 2.4V, V

SHDN

= 2V, TA= +25°C, unless otherwise noted.)

SUPPLY CURRENT vs. TEMPERATURE

9.8

9.7

9.6

9.5

9.4

9.3

SUPPLY CURRENT (mA)

9.2

9.1

9.0

-40 0-20 20 40 60 80

MAX2622

TEMPERATURE (°C)

MAX2623

VCO TUNING CURVE

1050

1000

950

TA = +25°C

900

FREQUENCY (MHz)

850

TA = -20°C

MAX2624

MAX2623

TA = -40°C

TA = +85°C

TA = +75°C

6

MAX2622-01

5

4

3

2

SUPPLY CURRENT (nA)

1

0

-40 0 20-20 40 60 80

1100

MAX2623-04

1050

1000

950

FREQUENCY (MHz)

900

SHUTDOWN SUPPLY CURRENT

MAX2624

vs. TEMPERATURE

TEMPERATURE (°C)

MAX2624

VCO TUNING CURVE

TA = -40°C

TA = +25°C

TA = +85°C

MAX2624-02

MAX2624-05

MAX2622

VCO TUNING CURVE

1000

TA = -40°C

950

TA = +25°C

900

850

FREQUENCY (MHz)

800

750

0 1.00.5 1.5 2.0 2.5 3.0

TA = +85°C

V

(V)

TUNE

PHASE NOISE

-60

-70

-80

-90

-100

PHASE NOISE (dBc)

-110

-120

MAX2622-03

MAX2622-06

800

0 1.00.5 1.5 2.0 2.5 3.0

V

(V)

TUNE

NORMALIZED HARMONIC OUTPUT SPECTRUM

OUTPUT POWER

f

O

FREQUENCY

∆ = 29.44dBc

∆ = 38.47dBc

2f

O

850

0 1.00.5 1.5 2.0 2.5 3.0

V

(V)

TUNE

2.0

MAX2622-07

3f

O

1.8

1.6

1.4

1.2

1.0

0.8

CURRENT (nA)

0.6

0.4

0.2

-130
10 100 1000

TUNE CURRENT vs. TEMPERATURE

MAX2622

MAX2623

MAX2624

0

-40 0-20 20 40 60 80
TEMPERATURE (°C)

FREQUENCY (kHz)

MAX2622-08

MAX2622/MAX2623/MAX2624

Detailed Description

Oscillator

The MAX2622/MAX2623/MAX2624 VCOs are imple­mented 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 con­trolled 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 frequen­cy 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.

Output Buffer

The oscillator signal from the core drives an output
buffer amplifier. The amplifier is constructed as a com­mon-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 VCCand GND pins to minimize
load-pulling effects. The amplifier boosts the oscillator
signal to a level suitable for driving most RF mixers.

Applications Information

Output Matching

Although the output amplifier internally provides a par-

tial match to 50Ω, a simple external shunt series capac­itor 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 pro­vide an appropriately low-impedance source. It may
incorporate an extra RC filter stage to reduce high-fre­quency 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 test­ing in order to filter the noise present on the voltage
source driving the tuning line.

Monolithic Voltage-Controlled Oscillators

4 _______________________________________________________________________________________

NAME FUNCTION

1

N.C. Not connected. Do not make any connections to this pin.

2 TUNE

Oscillator Frequency Tuning Voltage Input. High-impedance input with a voltage input range of 0.4V
(low frequency) to 2.4V (high frequency) adjustment.

PIN

3 GND

Ground Connection for Oscillator and Biasing. Requires a low-inductance connection to the circuit board
ground plane.

4

SHDN

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.

8 GND

Ground Connection for Output Buffer. Requires a low-inductance connection to the circuit board
ground plane.

7 OUT Buffered Oscillator Output. DC blocking capacitor required.

6 V

CC

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.

5 V

CC

Output Buffer DC Supply Voltage Connection. Bypass with a 100pF capacitor to GND for best high­frequency performance.

Pin Description

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 VCCpins as possible. For
long VCClines, 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.

MAX2622/MAX2623/MAX2624

Monolithic Voltage-Controlled Oscillators

_______________________________________________________________________________________ 5

Figure 1. Typical Application Circuit

Table 1. Output Matching Components for
50Ω Match

DEVICE C

SERIES

(pF)

MAX2622 2

MAX2623 1.5

MAX2624 1.3

C

SHUNT

(pF)

1

1

0.7

Pin Configuration

MAX2622

N.C.

MAX2623
MAX2624

FROM

SYNTHESIZER

LOOP FILTER

1k

SHDN

100pF

TUNE

OSCILLATOR

GND

SHDN

CORE

BIAS

TOP VIEW

GND

OUT

V

V

N.C.

GND

SHDN

C

SERIES

C

SHUNT

CC

CC

100pF

100pF

OUT TO MIXER/
SYNTHESIZER

V

CC

0.1µF

1

2

MAX2622
MAX2623

3

MAX2624

4

µMAX

87GND

OUTTUNE

V

6

5

V

CC

CC

MAX2622/MAX2623/MAX2624

Monolithic Voltage-Controlled Oscillators

6 _______________________________________________________________________________________

Package Information

8LUMAXD.EPS