19-4797; Rev 0; 2/99
L
MANUA
ION KIT HEET
AT
EVALU
TA S
WS DA
FOLLO
10MHz to 500MHz VCO Buffer Amplifiers
with Differential Outputs
General Description
Features
o
+2.7V to +5.5V Supply Range
o
Input Frequency Range
High: 10MHz to 500MHz (MAX2470/2471)
Low: 10MHz to 200MHz (MAX2470)
o
>14dB Power Gain at 200MHz
o
64dB Typical Reverse Isolation at 200MHz
o
Low-Distortion Output Drive
o
Ultra-Small SOT23-6 Package
o
High Input Impedance
o
Single-Ended (MAX2470) or Differential
(MAX2471) Inputs
MAX2470/MAX2471
The MAX2470/MAX2471 are flexible, low-cost, high-
reverse-isolation buffer amplifiers for applications with
discrete and module-based VCO designs. Both feature
differential 50Ω outputs for driving a single differential
(balanced) load or two separate single-ended (unbal-
anced) 50Ω loads. The MAX2470 offers a single-ended
input and has two selectable frequency ranges of oper-
ation: 10MHz to 500MHz and 10MHz to 200MHz. The
MAX2471 offers a differential input and operates from
10MHz to 500MHz. The MAX2470/MAX2471 also feature
high input impedance for maximum flexibility, enabling
them to be used with a variety of oscillator topologies.
High reverse isolation combined with low supply current
make them ideal for applications requiring high perfor-
mance with low power.
These devices are also ideal for use as active baluns.
The MAX2470 converts a single-ended input to a differ-
ential output. The MAX2471 is useful as a differential
buffer stage or to convert from a differential input to two
single-ended outputs.
The MAX2470 operates from a single +2.7V to +5.5V
supply. At -5dBm output power, it consumes 5.5mA in
the high-frequency range and only 3.6mA in the
low-frequency range. The MAX2471 operates from a
+2.7V to +5.5V single supply and consumes 5.5mA.
Both devices are available in ultra-small SOT23-6 plas-
tic packages, requiring minimal board space.
Ordering Information
PART
MAX2470EUT-T
MAX2471EUT-T
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
6 SOT23-6
6 SOT23-6
SOT TOP
MARK
AAAX
AAAY
Typical Operating Circuits
V
CC
HI/LO
Applications
Cellular and PCS Mobile Phones
ISM-Band Applications
Active Baluns
General-Purpose Buffers/Amplifiers
BIAS
MAX2470
OUT
IN
OUT
50Ω
Pin Configuration
GND
50Ω
TOP VIEW
OUT
1
6
V
CC
V
CC
BIAS
GND
2
MAX2471
OUT
50Ω
MAX2470
MAX2471
5
IN
IN
OUT
3
4
HI/LO (IN)
IN
OUT
50Ω
SOT23-6
( ) ARE FOR MAX2471
GND
________________________________________________________________
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.
10MHz to 500MHz VCO Buffer Amplifiers
with Differential Outputs
MAX2470/MAX2471
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ..............................................................-0.3V to +7V
IN to GND......-0.3V to (V
CC
+ 0.3V) or 3.7V (whichever is lower)
IN
to IN ..................................................................-2.2V to +2.2V
HI/LO to GND .............................................-0.3V to (V
CC
+ 0.3V)
Continuous Power Dissipation
SOT23-6 (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, 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 +5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +3V,
T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage Range
SYMBOL
V
CC
No signal
HI/LO = V
CC
Supply Current
I
CC
No signal
HI/LO = GND
HI/LO Input Level High
HI/LO Input Level Low
HI/LO Input Bias Current
V
IH
V
IL
I
IN
VHI/LO = GND or V
CC
-10
P
OUT
= -5dBm,
R
LOAD
= 100Ω diff.
No signal
P
OUT
= -5dBm,
R
LOAD
= 100Ω diff.
2.0
0.6
10
CONDITIONS
MIN
2.7
5.1
5.5
3.0
3.6
V
V
µA
4.5
mA
TYP
MAX
5.5
7.4
UNITS
V
AC ELECTRICAL CHARACTERISTICS—MAX2470
(V
CC
= +3V, HI/LO = V
CC
, all outputs are differentially measured between OUT and
OUT
driving a 50Ω load through a 180° hybrid,
T
A
= +25°C, unless otherwise noted.)
PARAMETER
Input Frequency Range
(Note 2)
SYMBOL
f
IN
HI/LO = V
CC
HI/LO = GND
f
IN
= 10MHz
HI/LO = V
CC
Gain (Note 3)
IS
21
I
2
HI/LO = GND
f
IN
= 200MHz
f
IN
= 500MHz,
T
A
= T
MIN
to T
MAX
f
IN
= 10MHz
f
IN
= 200MHz
f
IN
= 200MHz,
T
A
= T
MIN
to T
MAX
Voltage Gain (Note 4)
A
V
f
IN
= 10MHz, HI/LO = GND
f
OUT
= 500MHz,
HI/LO = V
CC
f
OUT
= 200MHz,
RHI/LO = GND
9.9
8.9
CONDITIONS
MIN
10
10
14.9
14.9
13.3
13.8
14.1
13.4
16
10.2
dB
10.2
15.0
V/V
15.3
dB
TYP
MAX
500
200
UNITS
MHz
Noise Figure
NF
R
SOURCE
= 50Ω
f
OUT
= 200MHz,
RHI/LO
= GND
2
_______________________________________________________________________________________
10MHz to 500MHz VCO Buffer Amplifiers
with Differential Outputs
AC ELECTRICAL CHARACTERISTICS—MAX2470 (continued)
(V
CC
= +3V, HI/LO = V
CC
, all outputs are differentially measured between OUT and
OUT
driving a 50Ω load through a 180° hybrid,
T
A
= +25°C, unless otherwise noted.)
PARAMETER
Maximum Output VSWR
(OUT,
OUT)
(Note 5)
SYMBOL
VSWR
OUT
CONDITIONS
10MHz < f
OUT
< 500MHz, HI/LO = V
CC
10MHz < f
OUT
< 200MHz, HI/LO = GND
HI/LO = V
CC
IS
12
I
2
HI/LO = GND
Isolation OUT to
OUT
(Note 7)
Harmonic Suppression
f
IN
= 100MHz
f
IN
= 500MHz
f
IN
= 100MHz
f
IN
= 200MHz
MIN
TYP
1.5:1
1.2:1
75
48
75
64
37
45
-26
-30
dB
dBc
dB
MAX
UNITS
MAX2470/MAX2471
Reverse Isolation
(Note 6)
f
IN
= 500MHz, HI/LO = V
CC
f
IN
= 200MHz, HI/LO = GND
f
IN
= 500MHz, P
OUT
= -5dBm, HI/LO = V
CC
f
IN
= 200MHz, P
OUT
= -5dBm, HI/LO = GND
AC ELECTRICAL CHARACTERISTICS—MAX2471
(Typical values are measured at V
CC
= +3V, T
A
= +25°C, unless otherwise noted.) (Note 8)
PARAMETER
Input Frequency Range
(Note 2)
Gain (Note 3)
Voltage Gain (Note 4)
Noise Figure
Maximum Output VSWR
(OUT,
OUT)
(Note 5)
Reverse Isolation
Isolation OUT to
OUT
(Note 7)
Harmonic Suppression
SYMBOL
f
IN
f
IN
= 10MHz
IS
21
I
2
A
V
NF
VSWR
OUT
IS
12
I
2
f
IN
= 200MHz
f
IN
= 500MHz, T
A
= T
MIN
to T
MAX
f
IN
= 10MHz
f
OUT
= 500MHz, R
SOURCE
= 50Ω
10MHz < f
OUT
< 500MHz
f
IN
= 100MHz
f
IN
= 500MHz
f
IN
= 500MHz
f
IN
= 500MHz, P
OUT
= -5dBm
11.3
CONDITIONS
MIN
10
15.9
16.9
15.6
16
8.4
1.5:1
74
57
35
-29
dB
dB
dBc
17.8
V/V
dB
dB
TYP
MAX
500
UNITS
MHz
Note 1:
Limits are 100% production tested at T
A
= +25°C. Limits over the entire operating temperature range are guaranteed by
design and characterization but are not production tested.
Note 2:
The part has been characterized over the specified frequency range. Operation outside of this range is possible but not
guaranteed.
Note 3:
Gain specified for P
OUT
= -5dBm.
Note 4:
Voltage gain measured with no input termination and no output load.
Note 5:
Output VSWR is a single-ended measurement for each OUT and
OUT.
Note 6:
OUT to IN isolation with
OUT
terminated with 50Ω.
Note 7:
Input terminated with 50Ω.
Note 8:
Unless otherwise noted: all inputs are differentially measured between IN and
IN
driven by a 50Ω load through a 180°
hybrid; all outputs are differentially measured between OUT and
OUT
driving a 50Ω load through a 180° hybrid.
_______________________________________________________________________________________
3
10MHz to 500MHz VCO Buffer Amplifiers
with Differential Outputs
MAX2470/MAX2471
Typical Operating Characteristics
(V
CC
= +3.0V, MAX2470 output and MAX2471 input and output measurements taken differentially, T
A
= +25°C, unless otherwise
noted.)
MAX2470
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(HI/LO = GND)
MAX2470/71-01
MAX2470 (HI/LO = V
CC
) AND MAX2471
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2470/71-02
MAX2470
OUTPUT POWER vs. INPUT POWER
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-11
-12
-13
-14
-15
-16
MAX2470/71-03
4.0
3.9
SUPPLY CURRENT (mA)
3.8
3.7
3.6
3.5
3.4
3.3
3.2
2.5
-5dBm OUTPUT POWER
f
IN
= 200MHz
HI/LO = GND
6.0
5.9
5.8
SUPPLY CURRENT (mA)
5.7
5.6
5.5
5.4
5.3
5.2
5.1
5.0
4.9
4.8
-5dBm OUTPUT POWER
f
IN
= 500MHz
HI/LO = GND (MAX2470)
OUTPUT POWER (dBm)
T
A
= +25°C
T
A
= +85°C
HI/LO = GND
f
IN
= 200MHz
HI/LO = V
CC
f
IN
= 500MHz
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
T
A
= -40°C
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
-30 -28 -26 -24 -22 -20 -18 -16 -14 -12 -10
INPUT POWER (dBm)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
MAX2470
TRANSDUCER GAIN vs. FREQUENCY
(HI/LO = GND)
MAX2470/71-04
MAX2470
TRANSDUCER GAIN vs. FREQUENCY
(HI/LO = V
CC
)
T
A
= -40°C
16.0
15.0
T
A
= +25°C
IS
21
I
2
(dB)
14.0
13.0
12.0
11.0
T
A
= +85°C
NOISE FIGURE (dB)
MAX2470/71-05
MAX2470
NOISE FIGURE vs. FREQUENCY
(HI/LO = GND)
HI/LO = GND
11.5
MAX2470/71-06
16.0
15.0
14.0
IS
21
I
2
(dB)
13.0
T
A
= +85°C
12.0
11.0
10.0
9.0
8.0
0
50
100
T
A
= +25°C
T
A
= -40°C
17.0
12.0
11.0
10.5
10.0
HI/LO = V
CC
9.5
0
100
200
300
400
500
0
50
100
FREQUENCY (MHz)
150
200
FREQUENCY (MHz)
HI/LO = GND
150
200
10.0
9.0
FREQUENCY (MHz)
MAX2470
NOISE FIGURE vs. FREQUENCY
(HI/LO = V
CC
)
MAX2470/71-07
MAX2470
REAL INPUT IMPEDANCE vs. FREQUENCY
MAX2470/71-08
MAX2470
IMAGINARY INPUT IMPEDANCE vs. FREQUENCY
HI/LO = V
CC
-500
-1000
-1500
-2000
MAX2470/71-09
12.0
HI/LO = V
CC
11.5
NOISE FIGURE (dB)
10,000
HI/LO = V
CC
0
1000
RE [Z
IN
] (Ω)
IM [Z
IN
] (Ω)
0
50 100 150 200 250 300 350 400 450 500
FREQUENCY (MHz)
11.0
100
10.5
10
10.0
0
100
200
300
400
500
FREQUENCY (MHz)
1
-2500
-3000
0
100
200
300
400
500
FREQUENCY (MHz)
4
_______________________________________________________________________________________
10MHz to 500MHz VCO Buffer Amplifiers
with Differential Outputs
Typical Operating Characteristics (continued)
(V
CC
= +3.0V, MAX2470 output and MAX2471 input and output measurements taken differentially, T
A
= +25°C unless otherwise
noted.)
MAX2470
OUTPUT VSWR vs. FREQUENCY
MAX2470/71-10
MAX2470/MAX2471
MAX2470
OUTPUT ISOLATION vs. FREQUENCY
MAX2470/71-11
MAX2471
OUTPUT POWER vs. INPUT POWER
0
OUTPUT POWER (dBm)
-2
-4
-6
-8
-10
-12
-14
500
-30 -28 -26 -24 -22 -20 -18 -16 -14 -12 -10
INPUT POWER (dBm)
f
IN
= 200MHz
f
IN
= 500MHz
MAX2470/71-12
1.50
HI/LO = V
CC
INPUT TERMINATED IN 50Ω
SINGLE-ENDED MEASUREMENT
OUTPUT VSWR
90
80
OUTPUT ISOLATION (dB)
70
60
50
40
30
OUT TO OUT
INPUT TERMINATED IN 50Ω
OUT TO IN
OUT TO IN
HI/LO = V
CC
SINGLE-ENDED
MEASUREMENT
2
OUT
1.25
OUT
1.00
0
100
200
300
400
500
FREQUENCY (MHz)
20
0
100
200
300
400
FREQUENCY (MHz)
MAX2471
DIFFERENTIAL TRANSDUCER
POWER GAIN vs. FREQUENCY
MAX2470/71-13
MAX2471
NOISE FIGURE vs. FREQUENCY
MAX2470/71-14
MAX2471
REAL INPUT IMPEDANCE vs. FREQUENCY
MAX2470/71-15
17.5
TRANSDUCER POWER GAIN (dB)
17.0
16.5
16.0
15.5
15.0
14.5
14.0
0
T
A
= +85°C
T
A
= -40°C
T
A
= +25°C
8.50
10,000
8.25
NOISE FIGURE (dB)
1000
8.00
RE [Z
IN
] (Ω)
100
7.75
7.50
10
7.25
50 100 150 200 250 300 350 400 450 500
FREQUENCY (MHz)
0
50 100 150 200 250 300 350 400 450 500
FREQUENCY (MHz)
1
0
50 100 150 200 250 300 350 400 450 500
FREQUENCY (MHz)
MAX2471
IMAGINARY INPUT IMPEDANCE
vs. FREQUENCY
MAX2470/71-16
MAX2471
OUTPUT VSWR vs. FREQUENCY
MAX2470/71-17
MAX2471
OUTPUT ISOLATION vs. FREQUENCY
SINGLE-ENDED
MEASUREMENT
OUT TO IN
MAX2470/71-18
500
1.50
INPUT TERMINATED
SINGLE-ENDED MEASUREMENT
VSWR OUT
1.25
90
80
OUTPUT ISOLATION (dB)
70
60
50
40
OUT TO OUT
30
INPUT TERMINATED IN 50Ω
OUTPUT VSWR
0
IM [Z
IN
] (Ω)
VSWR OUT
-500
-1000
0
100
200
300
400
500
FREQUENCY (MHz)
1.00
0
100
200
300
400
500
FREQUENCY (MHz)
20
0
100
200
300
400
500
FREQUENCY (MHz)
_______________________________________________________________________________________
5
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