19-1825; Rev 0; 10/00

NUAL
KIT MA
ATION EET
EVALU T A SH
WS DA
FOLLO
2.4GHz Monolithic
Voltage-Controlled Oscillators
General Description Features

MAX2750/MAX2751/MAX2752
The MAX2750/MAX2751/MAX2752 are self-contained volt- ♦ Guaranteed Frequency Tuning Range
age-controlled oscillators (VCOs) intended for use in the MAX2750: 2400MHz to 2500MHz (Zero IF)
2.4GHz to 2.5GHz ISM band. Each IC combines a fully MAX2751: 2120MHz to 2260MHz
integrated oscillator and output buffer in a miniature 8-pin (240MHz to 280MHz IF)
µMAX package. MAX2752: 2025MHz to 2165MHz
The inductor and varactor elements of the tank are inte- (335MHz to 375MHz IF)
grated on-chip, greatly simplifying application of the part. ♦ On-Chip Tank Circuit
The only required external components are a couple of
♦ Internally Matched Output Buffer Amplifier
supply bypass capacitors. The IC provides direct connec-
tion to the VCO tuning voltage input and the VCO buffer ♦ Low-Current Shutdown Mode
output. The tuning voltage input range is +0.4V to +2.4V,
♦ +2.7V to +5.5V Supply Voltage Range
and the oscillator frequency tuning range is factory adjust-
ed to provide guaranteed limits. The output signal is ♦ Miniature 8-Pin µMAX Package
buffered by an amplifier stage (internally matched to 50Ω)
to provide higher output power and isolate the device from
load impedance variations.
The MAX2750/MAX2751/MAX2752 operate over a +2.7V Ordering Information
to +5.5V supply voltage range. Internal regulation of the
PART TEMP. RANGE PIN-PACKAGE
oscillator supply voltage eliminates the need for an exter-
nal LDO regulator for the VCO. The IC also provides a dig- MAX2750EUA -40°C to +85°C 8 µMAX
itally controlled shutdown mode to permit implementation MAX2751EUA -40°C to +85°C 8 µMAX
of sophisticated power-supply management. In shutdown, MAX2752EUA -40°C to +85°C 8 µMAX
the supply current is reduced to less than 1µA.

________________________Applications Pin Configuration appears at end of data sheet.

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Home RF
2.4GHz Bluetooth ISM Proprietary Radio

Typical Operating Circuit

BYP
GND

TUNE OSCILLATOR OUT OUT TO MIXER/

TUNE
CORE SYNTHESIZER

GND
VCC1

MAX2750
MAX2751 VCC
MAX2752 VCC2
SHDN
SHDN BIAS

________________________________________________________________ Maxim Integrated Products 1

For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
 2.4GHz Monolithic
Voltage-Controlled Oscillators
ABSOLUTE MAXIMUM RATINGS
MAX2750/MAX2751/MAX2752

VCC to GND ..............................................................-0.3V to +6V Operating Temperature Range ...........................-40°C to +85°C

TUNE, SHDN, BYP, OUT to GND ...............-0.3V to (VCC + 0.3V) Junction Temperature ......................................................+150°C
Continuous Power Dissipation (TA = +70°C) Storage Temperature Range .............................-65°C to +150°C
8-Pin µMAX (derate 5.7mW/°C above TA = +70°C).....457mW Lead Temperature (soldering, 10s) .................................+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
(VCC = +2.7V to +5.5V, VTUNE = +0.4V to +2.4V, V SHDN ≤ +2V, OUT = connected to 50Ω load, TA = -40°C to +85°C. Typical values
are at VCC = +3.0V, TA = +25°C, unless otherwise noted.) (Note 1)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Supply Voltage 2.7 5.5 V
o
TA = +25 C 11.3 14.4
MAX2750
TA = -40oC to +85oC 14.1 17.0
TA = +25oC 9.7 12.1
Supply Current MAX2751 o o mA
TA = -40 C to +85 C 12.7 15.9
TA = +25oC 10 12.1
MAX2752
TA = -40oC to +85oC 12.8 15.2
Shutdown Supply Current 0.2 1 µA
SHDN Input Voltage Low 0.6 V
SHDN Input Voltage High 2.0 V
SHDN Input Current Low V SHDN ≤ 0.6V -2 2 µA
SHDN Input Current High V SHDN ≥ 2.0V -2 2 µA
TUNE Input Current 0.4 ≤ V TUNE ≤ 2.4V 0.02 nA

AC ELECTRICAL CHARACTERISTICS
(MAX2750/MAX2751/MAX2752 EV kit, VCC = +2.7V to +5.5V, VTUNE = +0.4V to +2.4V, V SHDN ≤ +2V, OUT = connected to 50Ω load,
TA = +25°C. Typical values are at VCC = +3.0V, unless otherwise noted.)

PARAMETER CONDITIONS MIN TYP MAX UNITS

MAX2750 2400 2500 MHz
Oscillator Guaranteed V TUNE = +0.4V to +2.4V,
MAX2751 2120 2260 MHz
Frequency Limits (Note1) TA = -40oC to +85oC
MAX2752 2025 2165 MHz
fOFFSET = 4MHz -125 dBc/Hz
Phase Noise
Noise floor -151 dBm/Hz
fOSC = 2400MHz, +3V 140
MAX2750
fOSC = 2500MHz, +3V 90
fOSC = 2120MHz, +3V 175
Tuning Gain (Note 2) MAX2751 MHz/V
fOSC = 2260MHz, +3V 110
fOSC = 2025MHz, +3V 170
MAX2752
fOSC = 2165MHz, +3V 105
Output Power -3 dBm
Return Loss 12 dB
Harmonics -30 dBc

2 _______________________________________________________________________________________
 2.4GHz Monolithic
Voltage-Controlled Oscillators

MAX2750/MAX2751/MAX2752
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2750/MAX2751/MAX2752 EV kit, VCC = +2.7V to +5.5V, VTUNE = +0.4V to +2.4V, V SHDN ≤ +2V, OUT = connected to 50Ω load,
TA = +25°C. Typical values are at VCC = +3.0V, unless otherwise noted.)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Load Pulling VSWR = 2:1, all phases 4 MHzp-p
Supply Pushing VCC stepped: +3.3V to +2.8V 1.3 MHz/V
Oscillator Turn-On Time (Note 3) Exiting shutdown 8 µs
Oscillator Turn-Off Time (Note 4) Entering shutdown 5 µs

Note 1: Specifications are production tested at TA = +25°C. Limits over temperature are guaranteed by design and characterization.
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.

Typical Operating Characteristics

(Circuit of Figure 1, VCC = +3.0V, VTUNE = +0.4V to +2.4V, V SHDN ≤ 2V, TA = +25°C, unless otherwise noted.)

MAX2750/MAX2751/MAX2752 MAX2750/MAX2751/MAX2752 MAX2750/MAX2751/MAX2752

SUPPLY CURRENT vs. TEMPERATURE SHUTDOWN CURRENT vs. TEMPERATURE TUNING CURRENT vs. TEMPERATURE
15 0.5 1.0

MAX2750/51/52 toc03
MAX2750/51/52 toc01

MAX2750/51/52 toc02

14
0.4 0.8
MAX2750
SHUTDOWN CURRENT (µA)

TUNE INPUT CURRENT (nA)

13
SUPPLY CURRENT (mA)

12 0.3 0.6
11
0.2 0.4
10
MAX2752
9
MAX2751 0.1 0.2
8

7 0 0
-40 -20 0 20 40 60 80 -40 -20 0 20 40 60 80 -40 -20 0 20 40 60 80
TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C)

MAX2750 MAX2751 MAX2752

VCO TUNING CURVE VCO TUNING CURVE VCO TUNING CURVE
2600
MAX2750/51/52 toc05

MAX2750/51/52 toc06
MAX2750/51/52 toc04

2350 2350

2500 TA = -40°C 2250 TA = -40°C 2250

FREQUENCY (MHz)

FREQUENCY (MHz)
FREQUENCY (MHz)

TA = -40°C

2150 2150
2400 TA = +25°C
TA = +25°C
2050 2050
TA = +25°C
2300 TA = +85°C
TA = +85°C
1950 1950
TA = +85°C

2200 1850 1850

0 0.5 1.0 1.5 2.0 2.5 3.0 0 0.5 1.0 1.5 2.0 2.5 3.0 0 0.5 1.0 1.5 2.0 2.5 3.0
VTUNE (V) VTUNE (V) VTUNE (V)

_______________________________________________________________________________________ 3
 2.4GHz Monolithic
Voltage-Controlled Oscillators
Typical Operating Characteristics (continued)
MAX2750/MAX2751/MAX2752

(Circuit of Figure 1, VCC = +3.0V, VTUNE = +0.4V to +2.4V, V SHDN ≤ 2V, TA = +25°C, unless otherwise noted.)
MAX2751 NORMALIZED HARMONIC
PHASE NOISE OUTPUT POWER vs. TEMPERATURE OUTPUT SPECTRUM
-50 -2

MAX2750/51/52 toc09
MAX2750/51/52 toc07

MAX2750/51/52 toc08
-60
∆ MKR
-70 -30.00dB ∆ = 30dBc

OUTPUT POWER (dBm)

PHASE NOISE (dBc/Hz)

OUTPUT POWER (dBm)

-80
-3 ∆ = 48dBc
-90
-100
-110
-120 -4

-130
-140
-150 -5
0.1 1 10 -40 -20 0 20 40 60 80 ƒO 2ƒO 3ƒO
OFFSET FREQUENCY (MHz) TEMPERATURE (°C) FREQUENCY

OSCILLATOR TURN-ON TIME OSCILLATOR TURN-ON TIME

0 0

MAX2750/51/52 toc11
MAX2750/51/52 toc10

-10 -10
-20 -20
OUTPUT POWER (dBm)
OUTPUT POWER (dBm)

-30 -30
-40 -40
-50 -50
-60 -60
4µs
-70 8µs -70
-80 -80
-90 -90
-100 -100
0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20
TIME (µs) TIME (µs)
Pin Description
PIN NAME FUNCTION

1 BYP VCO Bypass. Bypass with a 0.1µF capacitor to GND.

Oscillator Frequency Tuning Voltage Input. High-impedance input with a voltage input range of +0.4V
2 TUNE
(low frequency) to +2.4V (high frequency).
Ground Connection for Oscillator and Biasing. Requires a low-inductance connection to the circuit
3 GND
board ground plane.
Shutdown Logic Input. A high-impedance input logic level low disables the device and reduces
4 SHDN
supply current to less than 1.0µA. A logic level high enables the device.
Bias and Oscillator DC Supply Voltage Connection. Bypass separately from PIN6 with a 220pF
5 VCC1
capacitor to GND for low noise and low spurious content performance from the oscillator.
Output Buffer DC Supply Voltage Connection. Bypass separately from PIN5 with a 220pF capacitor to
6 VCC2
GND for best high frequency performance.
Buffered Oscillator Output. Incorporates an internal DC blocking capacitor. OUT is internally matched
7 OUT
to 50Ω.
Ground Connection for Output Buffer. Requires a low-inductance connection to the circuit board
8 GND
ground plane.
4 _______________________________________________________________________________________
 2.4GHz Monolithic
Voltage-Controlled Oscillators

MAX2750/MAX2751/MAX2752
BYP MAX2750
0.1µF MAX2751
MAX2752

GND

OSCILLATOR
FROM TUNE CORE OUT OUT TO MIXER/
SYNTHESIZER SYNTHESIZER

LOOP FILTER

220pF
VCC1
GND

VCC

SHDN VCC2
SHDN BIAS
220pF

Figure 1. Typical Application Circuit

Detailed Description Applications Information

Oscillator Tune Input
The MAX2750/MAX2751/MAX2752 VCOs are imple- The tuning input is typically connected to the output of
mented as an LC oscillator topology, integrating all of the PLL loop filter. The loop filter provides an appropri-
the tank components on-chip. This fully monolithic ately low-impedance source. The input may incorporate
approach provides an extremely easy-to-use VCO, an extra RC filter stage to reduce high-frequency noise
equivalent to a VCO module. The frequency is con- and spurious signals. Any excess noise on the tuning
trolled by a voltage applied to the TUNE pin, which is input is directly translated into FM noise, which can
internally connected to the varactor. The VCO core degrade the phase-noise performance of the oscillator.
uses a differential topology to provide a stable frequen- Therefore, it is important to minimize the noise intro-
cy versus supply voltage and improve the immunity to duced on the tuning input. A simple RC filter with low
load variations. In addition, there is a buffer amplifier corner frequency is needed during testing in order to
following the oscillator core to provide added isolation filter the noise present on the voltage source driving the
from load variations and to boost the output power. tuning line.
Output Buffer Layout Issues
The oscillator signal from the core drives an output Always use controlled impedance lines (microstrip,
buffer amplifier. The amplifier is internally matched to coplanar waveguide, etc.) for high-frequency signals.
50Ω including an on-chip DC blocking capacitor. No Always place decoupling capacitors as close to the
external DC blocking capacitor is required, eliminating VCC pins as possible; for long VCC lines, it may be nec-
the need for any external components. The output essary to add additional decoupling capacitors located
amplifier has its own VCC and GND pins to minimize further from the device. Always provide a low-induc-
load-pulling effects. The amplifier boosts the oscillator tance path to ground, and keep GND vias as close to
signal to a level suitable for driving most RF mixers. the device as possible. Thermal reliefs on GND pads
are not recommended.

_______________________________________________________________________________________ 5
 2.4GHz Monolithic
Voltage-Controlled Oscillators
Pin Configuration
MAX2750/MAX2751/MAX2752

Chip Information
TRANSISTOR COUNT: 176
TOP VIEW
PROCESS: BiPOLAR
BYP 1 8 GND

TUNE 2 7 OUT
MAX2750
GND 3 MAX2751 6 VCC2
MAX2752
SHDN 4 5 VCC1

µMAX

Package Information

8LUMAXD.EPS

6 _______________________________________________________________________________________