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19-1466; Rev 0; 6/99
NUAL KIT MA UATION TA SHEET EVAL WS DA FOLLO
500MHz to 2500MHz VCO Buffer Amplifiers
Features
o +2.7V to +5.5V Supply Range o 500MHz to 2500MHz Input Frequency Range o High Reverse Isolation: 49dB at 900MHz o Dual Open-Collector Outputs (MAX2472) o Adjustable -10dBm to -2dBm Output Power Control (MAX2473) o High Input Impedance: >250 at 900MHz o Ultra-Small SOT23-6 Package
General Description
The MAX2472/MAX2473 are flexible, wideband, highreverse-isolation buffer amplifiers. The MAX2472 has dual open-collector outputs capable of delivering -5dBm into 50 while maintaining harmonic suppression below -25dBc. The MAX2473 has a single open-collector output with a bias control pin to vary output power from -10dBm to -2dBm while maintaining harmonic suppression below -25dBc. The MAX2472/MAX2473's combination of high reverse isolation and low supply current makes them ideal for applications requiring high performance with low power. They feature high input impedance and open-collector outputs for maximum flexibility, enabling them to be used with a variety of oscillator topologies. Both the MAX2472 and MAX2473 operate from a single +2.7V to +5.5V supply. With VCC = +3.0V and -25dBm input power, the MAX2472 consumes 5.2mA, while the MAX2473 consumes only 2.7mA. Both devices are available in a tiny 6-pin SOT23 package requiring minimal board space.
MAX2472/MAX2473
Ordering Information
PART TEMP. RANGE PINPACKAGE 6 SOT23-6 6 SOT23-6 SOT TOP MARK AAAZ AABA
MAX2472EUT-T -40C to +85C MAX2473EUT-T -40C to +85C
Applications
Cellular and PCS Mobile Phones Private Mobile Radios ISM-Band Applications IF/RF Oscillators General-Purpose Buffers/Amplifiers
IN
Functional Diagrams
VCC BIAS OUT2
MAX2472
OUT1
Typical Operating Circuits appear at end of data sheet.
GND
GND
Pin Configuration
TOP VIEW
OUT1 (OUT) 1 6 VCC
VCC BIAS BIAS
MAX2473
GND 2
MAX2472 MAX2473
5
GND IN OUT
OUT2 (BIAS) 3
4
IN GND GND
SOT23-6
( ) ARE FOR MAX2473.
________________________________________________________________ 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.
500MHz to 2500MHz VCO Buffer Amplifiers MAX2472/MAX2473
ABSOLUTE MAXIMUM RATINGS
VCC to GND ..............................................................-0.3V to +7V OUT1, OUT2, BIAS to GND........................-0.3V to (VCC + 0.3V) Maximum BIAS Pin Current................................................150A Maximum Input Power....................................................+10dBm Continuous Power Dissipation SOT23-6 (derate 8.7mW/C above +70C)...................696mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10sec) .............................+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, PIN = -25dBm, IN driven from a 50 source, OUT_ LC-matched to 50, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +3V, TA = +25C.) (Note 1) PARAMETER Input Voltage Range SYMBOL VCC MAX2472 MAX2473, RBIAS = 23k Supply Current ICC MAX2473, RBIAS = 11k MAX2472 No drive MAX2473, RBIAS = 23k MAX2473, RBIAS = 11k CONDITIONS MIN 2.7 5.2 2.7 4.8 5.1 2.5 4.3 mA TYP MAX 5.5 8.0 UNITS V
AC ELECTRICAL CHARACTERISTICS--MAX2472
(Typical Operating Circuits, VCC = +3V, PIN = -25dBm, IN driven from a 50 source, OUT1 and OUT2 LC matched to 50, TA = +25C, unless otherwise noted.) PARAMETER Input Frequency Range (Note 2) SYMBOL fIN fIN = 600MHz Transducer Gain (IN to OUT2) fIN = 900MHz, TA = +25C S212 fIN = 900MHz, TA = TMIN to TMAX (Note 3) fIN = 1900MHz fIN = 2400MHz fIN = 600MHz Transducer Gain (IN to OUT1) Output 1dB Compression Point Reverse Isolation (IN to OUT2) S212 fIN = 900MHz fIN = 1900MHz fIN = 2400MHz POUT1dB fIN = 900MHz fIN = 600MHz S122 fIN = 900MHz fIN = 1900MHz fIN = 2400MHz 7.8 6.6 7.5 6.0 13.0 9.2 6.8 5.3 -3.2 43 40 30 26 dB dBm dB CONDITIONS MIN 500 14.0 10.2 12.2 14.6 dB TYP MAX 2500 UNITS MHz
2
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500MHz to 2500MHz VCO Buffer Amplifiers
AC ELECTRICAL CHARACTERISTICS--MAX2472 (continued)
(Typical Operating Circuits, VCC = +3V, PIN = -25dBm, IN driven from a 50 source, OUT1 and OUT2 LC matched to 50, TA = +25C, unless otherwise noted.) PARAMETER Reverse Isolation (IN to OUT1) SYMBOL fIN = 600MHz S122 fIN = 900MHz fIN = 1900MHz fIN = 2400MHz Noise Figure Isolation (OUT1 to OUT2) Harmonic Suppression NF fIN = 900MHz fIN = 1900MHz fIN = 900MHz POUT = -5dBm, fIN = 900MHz CONDITIONS MIN TYP 54 49 34 30 9.5 10.2 24 -25 dB dB dBc dB MAX UNITS
MAX2472/MAX2473
AC ELECTRICAL CHARACTERISTICS--MAX2473
(Typical Operating Circuits, VCC = +3V, PIN = -25dBm, RBIAS = 15k, IN driven from a 50 source, OUT LC matched to 50, TA = +25C, unless otherwise noted.) PARAMETER Input Frequency Range (Note 2) SYMBOL fIN fIN = 600MHz fIN = 900MHz, TA = +25C Transducer Gain S212 fIN = 900MHz, TA = TMIN to TMAX (Note 3) fIN = 1900MHz fIN = 2400MHz Output 1dB Compression Point POUT1dB fIN = 900MHz fIN = 600MHz Reverse Isolation S122 fIN = 900MHz fIN = 1900MHz fIN = 2400MHz Noise Figure Harmonic Suppression NF fIN = 900MHz fIN = 1900MHz POUT = -5dBm, fIN = 900MHz RBIAS = 23k RBIAS = 11k 6.8 6.4 7.6 7.2 -6.0 -0.9 50 48 35 29 9.2 9.9 -25 dB dBc dB dBm CONDITIONS MIN 500 14.8 11.8 16.8 19.0 dB TYP MAX 2500 UNITS MHz
Note 1: Limits are 100% production tested at TA = +25C. Limits over the entire operating temperature range are guaranteed by design and characterization but are not production tested. Note 2: This is the recommended operating frequency range. The parts have been characterized over the specified frequency range and production tested at 900MHz. Operation outside of this range is possible but not guaranteed. Note 3: Guaranteed by design and characterization.
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500MHz to 2500MHz VCO Buffer Amplifiers MAX2472/MAX2473
Typical Operating Characteristics
(MAX2472/MAX2473 EV kit, VCC = +3V, TA = +25C, unless otherwise noted.)
MAX2472
SUPPLY CURRENT vs. TEMPERATURE
PIN = -20dBm fIN = 900MHz
MAX2472 toc01
S21 2 vs. TEMPERATURE
14 12 10 fIN = 900MHz fIN = 1900MHz fIN = 600MHz PIN = -20dBm
MAX2472 toc02
7.0
6.0 ICC (mA) VCC = 5V VCC = 3V 5.0 S21 2 (dB)
8 6 4 2
fIN = 2400MHz
4.0 -40
-20
0
20
40
60
80
0 -50
-30
-10
10
30
50
70
90
TEMPERATURE (C)
TEMPERATURE (C)
S21 2 vs. OUTPUT POWER
MAX2472 toc03
S11
MAX2472 toc06
14 fIN = 600MHz 12 10 S21 2 (dB) fIN = 900MHz 8 6 4 2 FOR OUT1 WITH OUT2 REACTIVELY MATCHED AND TERMINATED -6 -4 -2 0 fIN = 2400MHz fIN = 1900MHz
A D C B
0 -20 -18 -16 -14 -12 -10 -8 POUT (dBm)
FOR OUT2 WITH OUT1 BIASED AND TERMINATED
A: fIN = 600MHz B: fIN = 900MHz C: fIN = 1900MHz D: fIN = 2400MHz
S21
MAX2472 toc07
S12
MAX2472 toc08
S22
MAX2472 toc09
D C D C
BA
A D B A C A: fIN = 600MHz B: fIN = 900MHz C: fIN = 1900MHz D: fIN = 2400MHz (0.1 UNITS FULL SCALE) FOR OUT2 WITH OUT1 BIASED AND TERMINATED A: fIN = 600MHz B: fIN = 900MHz C: fIN = 1900MHz D: fIN = 2400MHz FOR OUT2 WITH OUT1 BIASED AND TERMINATED A: fIN = 600MHz B: fIN = 900MHz C: fIN = 1900MHz D: fIN = 2400MHz B
(3 UNITS FULL SCALE) FOR OUT2 WITH OUT1 BIASED AND TERMINATED
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500MHz to 2500MHz VCO Buffer Amplifiers
Typical Operating Characteristics (continued)
(MAX2472/MAX2473 EV kit, VCC = +3V, TA = +25C, unless otherwise noted.)
MAX2472/MAX2473
MAX2472 SCATTERING PARAMETERS (IN to OUT 2)
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500MHz to 2500MHz VCO Buffer Amplifiers MAX2472/MAX2473
Typical Operating Characteristics (continued)
(MAX2472/MAX2473 EV kit, VCC = +3V, TA = +25C, unless otherwise noted.)
MAX2473
SUPPLY CURRENT vs. RBIAS
MAX2472 toc11
S21 2 vs. TEMPERATURE
MAX2472 toc12
S21 2 vs. OUTPUT POWER
18 16 14 S21 2 (dB) fIN = 2400MHz
MAX2472 toc13a
10 9 8 7 ICC (mA) 6 5 4 3 2 1 0 50 45 40 35 30 25 20 15 VCC = 3V VCC = 5V
18 16 14 12 S21 2 (dB) 10 8 6 4 2 fIN = 900MHz fIN = 1900MHz fIN = 600MHz
PIN = -20dBm RBIAS = 15k
20
12 10 8 6 RBIAS = 15k RBIAS = 22k RBIAS = 11k
fIN = 2400MHz
4 2
10
0 -50
-25
0
25
50
75
100
0 -25
-20
-15
-10
-5
0
RBIAS (k)
TEMPERATURE (C)
POUT (dBm)
S21 2 vs. OUTPUT POWER
MAX2472 toc13b
S21 2 vs. OUTPUT POWER
MAX2472 toc13c
S21 2 vs. OUTPUT POWER
18 16 14 S21 2 (dB) 12 10 8 6 4 2 RBIAS = 15k RBIAS = 22k fIN = 600MHz RBIAS = 11k
MAX2472 toc13d
20 18 16 14 S21 2 (dB) 12 10 8 6 4 2 0 -20 -15 RBIAS = 22k -10 POUT (dBm) -5 RBIAS = 15k RBIAS = 11k fIN = 1900MHz
20 18 16 14 S21 2 (dB) 12 10 8 6 4 2 RBIAS = 15k RBIAS = 22k RBIAS = 11k fIN = 900MHz
20
0
0 -20
-16
-12
-8
-4
0
0 -20
-15
-10
-5
0
5
POUT (dBm)
POUT (dBm)
6
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500MHz to 2500MHz VCO Buffer Amplifiers
Typical Operating Characteristics (continued)
(MAX2472/MAX2473 EV kit, VCC = +3V, TA = +25C, unless otherwise noted.)
MAX2472/MAX2473
MAX2473
REVERSE ISOLATION vs. RBIAS
fIN = 900MHz -35 REVERSE ISOLATION (dB) -40 -45 -50 -55 -60
MAX2472 toc15
S11
MAX2472 toc16
-30
D
A B C
0
5
10
15
20
25
30
35
40
RBIAS = 15k
RBIAS (k)
A: fIN = 600MHz B: fIN = 900MHz C: fIN = 1900MHz D: fIN = 2400MHz
S21
MAX2472 toc18
S12
MAX2472 toc17
S22
MAX2472 toc19
D CB D C
A A B D
B
A A: fIN = 600MHz B: fIN = 900MHz C: fIN = 1900MHz D: fIN = 2400MHz A: fIN = 600MHz B: fIN = 900MHz C: fIN = 1900MHz D: fIN = 2400MHz
C (0.1 UNITS FULL SCALE) RBIAS = 15k RBIAS = 15k A: fIN = 600MHz B: fIN = 900MHz C: fIN = 1900MHz D: fIN = 2400MHz
(3 UNITS FULL SCALE) RBIAS = 15k
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500MHz to 2500MHz VCO Buffer Amplifiers MAX2472/MAX2473
Typical Operating Characteristics (continued)
(MAX2472/MAX2473 EV kit, VCC = +3V, TA = +25C, unless otherwise noted.)
MAX2473 SCATTERING PARAMETERS (IN to OUT)
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500MHz to 2500MHz VCO Buffer Amplifiers
Pin Description
PIN MAX2472 1 -- 2, 5 3 MAX2473 -- 1 2, 5 -- NAME OUT1 OUT GND OUT2 FUNCTION Open-Collector Buffer Output 1. Connect to VCC via a resistor or inductor/choke. AC-coupling to the output is required. Open-Collector Buffer Output. Connect to VCC via a resistor or inductor/choke. AC-coupling to the output is required. RF Ground. Connect to the ground plane as close to the IC as possible to minimize trace inductance. Open-Collector Buffer Output 2. Connect to VCC via a resistor or inductor/choke. AC-coupling to the output is required. Bias Resistor Connection. Connect a resistor from BIAS to GND to set the output stage bias current and gain. To choose RBIAS, refer to the Typical Operating Characteristics for the MAX2473. High-Impedance Input to the Buffer Amplifier Supply Voltage Input: +2.7V < VCC < +5.5V
MAX2472/MAX2473
-- 4 6
3 4 6
BIAS IN VCC
Table 1. Output Matching Components
OPERATING FREQUENCY (MHz) 600 900 1900 2400 LMATCH 22nH Coilcraft 0603HS-22NTJBC 12nH Coilcraft 0603HS-12NTJBC 2.2nH Murata LQG11AZN2500 1.2nH Murata LQG11AINZS00 CMATCH 1.5pF Murata GRM39COG1R5B50V 1pF Murata GRM39COG1R0B50V 1pF Murata GRM39COG1R0B50V 1pF Murata GRM39COG1R0B50V
Detailed Description
The MAX2472/MAX2473 are ideal replacements for discrete solutions where a VCO output must drive more than one input, especially where high reverse isolation and low supply currents are mandatory. The MAX2472 features a two-stage wideband architecture with a highinput-impedance common-emitter amplifier followed by
two separate open-collector output stages. The MAX2473 features a two-stage wideband architecture with a high-input-impedance common-emitter amplifier followed by one open-collector output stage, with the added feature of output power control. Using values for RBIAS from 11k to 23k allows the output power of the MAX2473 to range from -2dBm to -10dBm.
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500MHz to 2500MHz VCO Buffer Amplifiers MAX2472/MAX2473
VCC (PIN 6) VCC (PIN 6)
250 1.3pF IN (PIN 4) 1k
INTERNAL 1.2V REFERENCE 1k BIAS (PIN 3)
GND (PIN 2) 33
Figure 3. BIAS Structure (MAX2473 only)
GND (PIN 5)
Figure 1. Input Structure
VCC (PIN 6)
2k OUT
the MAX2472/MAX2473 from the S parameter tables in the Typical Operating Characteristics. Terminate the buffer input with a shunt resistor "RTERM" such that RTERM || RE[S11] = 50, and use a series blocking capacitor between the shunt resistor and the device input. This provides a very stable 50 termination and increases reverse isolation. For those applications needing both high gain and good input match, reactively match the buffer inputs to 50 with simple twoelement matching circuits. Figure 1 shows an equivalent input circuit of the MAX2472/MAX2473 IN pin.
Output Considerations
The MAX2472/MAX2473 outputs are configured as open-collector output stages, allowing maximum flexibility. To achieve maximum gain and output drive, reactively match these outputs with a shunt inductor/choke to VCC followed by a series capacitor (DC block). For applications not requiring high gain and output drive (PLL prescaler), use a simple resistor to VCC followed by a DC blocking capacitor. Figure 2 shows an equivalent circuit of the MAX2472/MAX2473 OUT pin(s). Figure 3 shows an equivalent circuit of the MAX2473 BIAS pin.
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GND (PIN 2)
Figure 2. Output Structure
Applications Information
Input Considerations
The MAX2472/MAX2473 offer high-impedance inputs ideal for low-distortion buffering of a VCO. For applications with discrete transistor-based oscillator designs, simply AC-couple the oscillator directly to the input; the buffer's high input impedance results in minimal loading on the oscillator. For use with 50 VCO modules, determine the approximate input impedance (S11) of
Output Matching Circuit
Table 1 lists recommended values for lumped-element output matching circuits at certain frequencies. For frequencies other than those specified, use the parameters given in the Typical Operating Characteristics.
Layout and Power-Supply Bypassing
A properly designed PC board is essential to any RF/microwave circuit. Be sure to use controlled impedance lines on all high-frequency inputs and outputs. Bypass the power supply with decoupling capacitors
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500MHz to 2500MHz VCO Buffer Amplifiers MAX2472/MAX2473
as close to the VCC pin as possible. For long VCC lines (inductive), it may be necessary to add additional decoupling capacitors located farther away from the device package. Proper connection of the GND pins is essential to achieving maximum reverse isolation. If the PC board uses a topside RF ground, connect both GND pins directly to it. For a board where the ground plane is not on the component side, the best technique is to connect the GND pins to the board with plated throughholes (vias) to the ground plane, located as close to the package as possible.
Typical Operating Circuits
VCC VCC
0.01F VCC BIAS
1.0F
30pF
0.01F
LMATCH TO MIXER
MAX2472
VCO IN 100pF
OUT2
CMATCH
OUT1
CMATCH TO MIXER OR PLL
GND
GND LMATCH
30pF VCC
0.01F
VCC
0.01F VCC BIAS
1.0F RBIAS BIAS
MAX2473
VCO IN 100pF CMATCH TO MIXER
GND
GND
LMATCH
30pF VCC
0.01F
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500MHz to 2500MHz VCO Buffer Amplifiers MAX2472/MAX2473
Package Information
6LSOT.EPS
Chip Information
TRANSISTOR COUNT: 109
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