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19-0831; Rev 0; 6/07
2.4GHz Monolithic Voltage-Controlled Oscillator for Automotive
General Description
The MAX2750AUA is a self-contained voltage-controlled oscillator (VCO) intended for use over the 2370MHz to 2470MHz frequency range. The IC combines a fully integrated oscillator and output buffer in a miniature 8-pin MAX(R) package. The inductor and varactor elements of the tank are integrated on-chip, greatly simplifying application of the part. The only required external components are a couple of supply bypass capacitors. The IC provides direct connection to the VCO tuning voltage input and the VCO buffer output. The tuning voltage input range is +0.4V to +2.4V, and the oscillator frequency tuning range is factory adjusted to provide guaranteed limits. The output signal is buffered by an amplifier stage (internally matched to 50) to provide higher output power and isolate the device from load impedance variations. The MAX2750AUA operates over a +2.7V to +5.5V supply voltage range. Internal regulation of the oscillator supply voltage eliminates the need for an external LDO regulator for the VCO. The IC also provides a digitally controlled shutdown mode to permit implementation of sophisticated power-supply management. In shutdown, the supply current is reduced to less than 2A.
Features
Guaranteed Frequency Tuning Range: 2370MHz to 2470MHz On-Chip Tank Circuit Internally Matched Output Buffer Amplifier Low-Current Shutdown Mode +2.7V to +5.5V Supply Voltage Range Miniature 8-Pin MAX Package -40C to +125C Temperature Range
MAX2750AUA
Ordering Information
PART TEMP RANGE PINPACKAGE 8 MAX PKG CODE U8-1
MAX2750AUA+ -40C to +125C
+Denotes a lead-free package.
Pin Configuration appears at end of data sheet.
________________________Applications
Automotive 2.4GHz ISM Band
MAX is a registered trademark of Maxim Integrated Products, Inc.
Typical Operating Circuit
BYP GND
TUNE
TUNE
OSCILLATOR CORE
OUT
OUT TO MIXER/ SYNTHESIZER
GND VCC1
MAX2750AUA
VCC SHDN SHDN VCC2 BIAS
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
2.4GHz Monolithic Voltage-Controlled Oscillator for Automotive MAX2750AUA
ABSOLUTE MAXIMUM RATINGS
VCC to GND ..............................................................-0.3V to +6V TUNE, SHDN, BYP, OUT to GND ...............-0.3V to (VCC + 0.3V) Continuous Power Dissipation (TA = +70C) 8-Pin MAX (derate 5.7mW/C above TA = +70C).....457mW Operating Temperature Range .........................-40C to +125C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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
(VCC = +2.7V to +5.5V, VTUNE = +0.4V to +2.4V, V SHDN +2V, OUT = connected to 50 load, TA = -40C to +125C. Typical values are at VCC = +3.0V, TA = +25C, unless otherwise noted.) (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 V SHDN 0.4 0.6V 2.0V 2.4V 2.0 -2 -2 20 +2 +2 TA = +25oC TA = -40C to +125C CONDITIONS MIN 2.7 11.3 16.0 2 0.6 TYP MAX 5.5 14.4 21.0 UNITS V mA A V V A A nA
V TUNE
AC ELECTRICAL CHARACTERISTICS
(MAX2750AUA EV kit, VCC = +2.7V to +5.5V, VTUNE = +0.4V to +2.4V, V SHDN +2V, OUT = connected to 50 load, TA = +25C. Typical values are at VCC = +3.0V, unless otherwise noted.) (Note 1)
PARAMETER Oscillator Guaranteed Frequency Limits Phase Noise Tuning Gain (Note 2) Output Power Return Loss Harmonics Load Pulling Supply Pushing Oscillator Turn-On Time Oscillator Turn-Off Time VSWR = 2:1, all phases VCC stepped: +3.3V to +2.8V Exiting shutdown (Note 3) Entering shutdown (Note 4) CONDITIONS V TUNE = +0.4V to +2.4V, TA = -40 C to +125 C (Note1) f OFFSET = 4MHz Noise floor f OSC = 2370MHz, +3V f OSC = 2470MHz, +3V
o o
MIN 2370
TYP
MAX 2470
UNITS MHz dBc/Hz dBm/Hz MHz/V dBm dB dBc MHz P-P MHz/V s s
-125 -151 140 90 -3 12 -30 4 1.3 8 5
Note 1: Minimum and maximum limits are guaranteed by production test at TA = +25C and TA = +125C. Minimum and maximum limits are guaranteed by design and characterization at TA = -40C. Note 2: Tuning gain is measured at the oscillator's guaranteed frequency limits. Note 3: Turn-on time to within 3dB of final output power Note 4: Turn-off time to output power of -10dBm. 2 _______________________________________________________________________________________
2.4GHz Monolithic Voltage-Controlled Oscillator for Automotive
Typical Operating Characterstics
(Circuit of Figure 1, VCC = +3.0V, VTUNE = +0.4V to +2.4V, V SHDN 2V, TA = +25C, unless otherwise noted.)
NORMALIZED HARMONIC OUTPUT SPECTRUM
MAX2750AUA toc01
MAX2750AUA
PHASE NOISE
-50 -60 -70 PHASE NOISE (dBc/Hz) -80 -90 -100 -110 -120 -130 -140 -150 0.1 1 OFFSET FREQUENCY (MHz) 10
MKR -30.00dB OUTPUT POWER (dBm)
= 30dBc = 48dBc
O
2O FREQUENCY
3O
OSCILLATOR TURN-ON TIME
MAX2750AUA toc03
OSCILLATOR TURN-ON TIME
-10 -20 OUTPUT POWER (dBm) -30 -40 -50 -60 -70 -80 -90 -100 4s
MAX2750AUA toc04
0 -10 -20 OUTPUT POWER (dBm) -30 -40 -50 -60 -70 -80 -90 -100 0 2 4 6 8 8s
0
10 12 14 16 18 20
0
2
4
6
8
10 12 14 16 18 20
TIME (s)
TIME (s)
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MAX2750AUA toc02
3
2.4GHz Monolithic Voltage-Controlled Oscillator for Automotive MAX2750AUA
Pin Description
PIN 1 2 3 4 5 6 7 8 NAME BYP TUNE GND SHDN VCC1 VCC2 OUT GND FUNCTION VCO Bypass. Bypass with a 0.1F capacitor to GND. Oscillator Frequency Tuning Voltage Input. High-impedance input with a voltage input range of +0.4V (low frequency) to +2.4V (high frequency). 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 less than 1.0A. A logic-level high enables the device. Bias and Oscillator DC Supply Voltage Connection. Bypass separately from pin 6 with a 220pF capacitor to GND for low noise and low spurious content performance from the oscillator. Output Buffer DC Supply Voltage Connection. Bypass separately from pin 5 with a 220pF capacitor to GND for best high frequency performance. Buffered Oscillator Output. Incorporates an internal DC-blocking capacitor. OUT is internally matched to 50 . Ground Connection for Output Buffer. Requires a low-inductance connection to the circuit board ground plane.
BYP 0.1F
MAX2750AUA
GND
FROM SYNTHESIZER LOOP FILTER
TUNE
OSCILLATOR CORE
OUT
OUT TO MIXER/ SYNTHESIZER
220pF VCC1 GND VCC SHDN SHDN BIAS VCC2 220pF
Figure 1. Typical Application Circuit
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_______________________________________________________________________________________
2.4GHz Monolithic Voltage-Controlled Oscillator for Automotive MAX2750AUA
Detailed Description
Oscillator
The MAX2750AUA VCO is 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.
Layout Issues
Always use controlled impedance lines (microstrip, coplanar waveguide, etc.) for high-frequency signals. Always place decoupling capacitors as close as possible to the VCC pins; for long VCC lines, it may be necessary to add additional decoupling capacitors located further from the device. Always provide a low-inductance path to ground, and keep GND vias as close as possible to the device. Thermal reliefs on GND pads are not recommended.
Pin Configuration
TOP VIEW +
BYP 1 TUNE 2 8 7 GND OUT VCC2 VCC1
Output Buffer
The oscillator signal from the core drives an output buffer amplifier. The amplifier is internally matched to 50 including an on-chip DC-blocking capacitor. No external DC-blocking capacitor is required, eliminating the need for any external components. The output amplifier has its own VCC and GND pins to minimize load-pulling effects. The amplifier boosts the oscillator signal to a level suitable for driving most RF mixers.
MAX2750AUA
GND 3 6 5 SHDN 4
Applications Information
Tune Input
The tuning input is typically connected to the output of the PLL loop filter. The loop filter provides an appropriately low-impedance source. The input 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 is needed during testing to filter the noise present on the voltage source driving the tuning line.
MAX
_______________________________________________________________________________________
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2.4GHz Monolithic Voltage-Controlled Oscillator for Automotive MAX2750AUA
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
8
4X S
8
0.500.1 0.60.1
E
H
0.60.1
1
D
1
DIM A A1 A2 b c D e E H L
BOTTOM VIEW
S
INCHES MIN MAX 0.043 0.002 0.006 0.030 0.037 0.010 0.014 0.005 0.007 0.116 0.120 0.0256 BSC 0.116 0.120 0.188 0.198 0.016 0.026 6 0 0.0207 BSC
MILLIMETERS MAX MIN 1.10 0.05 0.15 0.75 0.95 0.25 0.36 0.13 0.18 2.95 3.05 0.65 BSC 2.95 3.05 5.03 4.78 0.66 0.41 0 6 0.5250 BSC
TOP VIEW
A2
A1 A e c b L
FRONT VIEW
SIDE VIEW
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE, 8L uMAX/uSOP
DOCUMENT CONTROL NO.
APPROVAL
21-0036
REV.
J
1
1
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
8LUMAXD.EPS

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