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General Description
The MAX2680/MAX2681/MAX2682 miniature, low-cost,
low-noise downconverter mixers are designed for low-
voltage operation and are ideal for use in portable com-
munications equipment. Signals at the RF input port are
mixed with signals at the local oscillator (LO) port using a
double-balanced mixer. These downconverter mixers
operate with RF input frequencies between 400MHz and
2500MHz, and downconvert to IF output frequencies
between 10MHz and 500MHz.
The MAX2680/MAX2681/MAX2682 operate from a sin-
gle +2.7V to +5.5V supply, allowing them to be pow-
ered directly from a 3-cell NiCd or a 1-cell Lithium
battery. These devices offer a wide range of supply
currents and input intercept (IIP3) levels to optimize
system performance. Additionally, each device features
a low-power shutdown mode in which it typically draws
less than 0.1µA of supply current. Consult the Selector
Guide for various combinations of IIP3 and supply cur-
rent.
The MAX2680/MAX2681/MAX2682 are manufactured
on a high-frequency, low-noise, advanced silicon-ger-
manium process and are offered in the space-saving
6-pin SOT23 package.
Applications
400MHz/900MHz/2.4GHz ISM-Band Radios
Personal Communications Systems (PCS)
Cellular and Cordless Phones
Wireless Local Loop
IEEE-802.11 and Wireless Data
Features
♦400MHz to 2.5GHz Operation
♦+2.7V to +5.5V Single-Supply Operation
♦Low Noise Figure: 6.3dB at 900MHz (MAX2680)
♦High Input Third-Order Intercept Point
(IIP3 at 2450MHz)
-6.9dBm at 5.0mA (MAX2680)
+1.0dBm at 8.7mA (MAX2681)
+3.2dBm at 15.0mA (MAX2682)
♦<0.1µA Low-Power Shutdown Mode
♦Ultra-Small Surface-Mount Packaging
MAX2680/MAX2681/MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
________________________________________________________________ Maxim Integrated Products 1
GND
IFOUTRFIN
16SHDN
5VCC
LO
MAX2680
MAX2681
MAX2682
SOT23-6
TOP VIEW
2
34
19-4786; Rev 2; 8/03
PART
MAX2680EUT-T
MAX2681EUT-T
MAX2682EUT-T -40°C to +85°C
-40°C to +85°C
-40°C to +85°C
TEMP RANGE PIN-
PACKAGE
6 SOT23-6
6 SOT23-6
6 SOT23-6
EVALUATION KIT
AVAILABLE
Pin Configuration
Ordering Information
SOT
TOP MARK
AAAR
AAAS
AAAT
8.7MAX2681
5.0MAX2680
Selector Guide
PART ICC
(mA)
-6.1
IIP3
(dBm)
-12.9
7.0
NF
(dB)
6.3
14.2
GAIN
(dB)
11.6
900MHz
+0.5
IIP3
(dBm)
-8.2
11.1
NF
(dB)
8.3
8.4
GAIN
(dB)
7.6
1950MHz
+1.0
IIP3
(dBm)
-6.9
12.7
NF
(dB)
11.7
7.7
GAIN
(dB)
7.0
2450MHz
-1.815.0MAX2682 6.5 14.7 +4.4 10.2 10.4 +3.2 13.4 7.9
Typical Operating Circuit appears at end of data sheet.
FREQUENCY
MAX2680/MAX2681/MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(VCC = +2.7V to +5.5V, SHDN = +2V, TA= TMIN to TMAX unless otherwise noted. Typical values are at VCC = +3V and TA= +25°C.
Minimum and maximum values are guaranteed over temperature by design and characterization.)
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.
VCC to GND ..........................................................-0.3V to +6.0V
RFIN Input Power (50ΩSource).....................................+10dBm
LO Input Power (50ΩSource) ........................................+10dBm
SHDN, IFOUT, RFIN to GND ......................-0.3V to (VCC + 0.3V)
LO to GND..........................................(VCC - 1V) to (VCC + 0.3V)
Continuous Power Dissipation (TA= +70°C)
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 +160°C
Lead Temperature (soldering, 10s) .................................+300°C
MAX2682
MAX2681
MAX2680
SHDN = 0.5V
0 < SHDN < VCC
CONDITIONS
mA
15.0 21.8
ICC
Operating Supply Current 8.7 12.7
5.0 7.7
µA0.05 5ICC
Shutdown Supply Current
V2.0VIH
Shutdown Input Voltage High
V0.5VIL
Shutdown Input Voltage Low
µA0.2ISHDN
Shutdown Input Bias Current
UNITSMIN TYP MAXSYMBOLPARAMETER
(Notes 1, 2)
(Notes 1, 2)
50Ωsource impedance
fRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz
fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
fRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
(Notes 1, 2)
fRF = 400MHz, fLO = 445MHz, fIF = 45MHz
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1)
fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz
CONDITIONS
1.5:1LO Input VSWR
dB
11.7
Noise Figure (Single Sideband) 8.3
6.3
dBm
-6.9
Input Third-Order Intercept Point
(Note 3)
MHz400 2500LO Frequency Range
MHz400 2500RF Frequency Range
-8.2
-12.9
dB
7.0
Conversion Power Gain
MHz10 500IF Frequency Range
7.3
11.6
5.7 7.6 8.6
UNITSMIN TYP MAXPARAMETER
AC ELECTRICAL CHARACTERISTICS
(MAX2680/1/2 EV Kit, VCC = SHDN = +3.0V, TA= +25°C, unless otherwise noted. RFIN and IFOUT matched to 50Ω. PLO = -5dBm,
PRFIN = -25dBm.)
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz,
TA= TMIN to TMAX (Note 1) dB1.9 2.4Gain Variation Over Temperature
fLO = 1880MHz dBm-22LO Leakage at IFOUT Port
MAX2680
CAUTION! ESD SENSITIVE DEVICE
MAX2680/MAX2681/MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
_______________________________________________________________________________________ 3
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2680/1/2 EV Kit, VCC = SHDN = +3.0V, TA= +25°C, unless otherwise noted. RFIN and IFOUT matched to 50Ω. PLO = -5dBm,
PRFIN = -25dBm.)
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz,
TA= TMIN to TMAX (Note 1) dB1.7 2.3
(Notes 1, 2)
Gain Variation Over Temperature
fLO = 1880MHz
(Notes 1, 2)
fLO = 1880MHz
dBm
50Ωsource impedance
fRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz
fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
fRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz
-27
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
(Notes 1, 2)
fRF = 400MHz, fLO = 445MHz, fIF = 45MHz
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1)
fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz
CONDITIONS
LO Leakage at RFIN Port
dBm-23LO Leakage at IFOUT Port
fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4) dBm-65IF/2 Spurious Response
1.5:1LO Input VSWR
dB
12.7
Noise Figure (Single Sideband) 11.1
7.0
dBm
+1.0
Input Third-Order Intercept Point
(Note 3)
MHz400 2500LO Frequency Range
MHz400 2500RF Frequency Range
+0.5
-6.1
dB
7.7
Conversion Power Gain
MHz10 500IF Frequency Range
11.0
14.2
6.7 8.4 9.4
UNITSMIN TYP MAXPARAMETER
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz,
TA= TMIN to TMAX (Note 1) dB2.1 3.2
(Notes 1, 2)
Gain Variation Over Temperature
(Notes 1, 2)
fRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz
fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
(Notes 1, 2)
fRF = 400MHz, fLO = 445MHz, fIF = 45MHz
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1)
fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz
dBm
+3.2
Input Third-Order Intercept Point
(Note 3)
MHz400 2500LO Frequency Range
MHz400 2500RF Frequency Range
+4.4
-1.8
dB
7.9
Conversion Power Gain
MHz10 500IF Frequency Range
13.4
14.7
8.7 10.4 11.7
fRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
dB
13.4
Noise Figure (Single Sideband) 10.2
6.5
fLO = 1880MHz dBm-26LO Leakage at RFIN Port
fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4) dBm-51IF/2 Spurious Response
MAX2681
MAX2682
2
3
5
4
6
7
2.5 3.53.0 4.0 4.5 5.0 5.5
MAX2680
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2680/1/2-01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +85°C TA = +25°C
TA = -40°C
SHDN = VCC
5
6
8
7
9
10
2.5 3.53.0 4.0 4.5 5.0 5.5
MAX2681
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2680/1/2-02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +85°C
SHDN = VCC
TA = +25°C
TA = -40°C
8
11
10
9
12
13
14
15
16
17
18
2.5 3.53.0 4.0 4.5 5.0 5.5
MAX2682
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2680/1/2-03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +85°C
TA = +25°CTA = -40°C
SHDN = VCC
MAX2680/MAX2681/MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
4 _______________________________________________________________________________________
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2680/1/2 EV Kit, VCC = SHDN = +3.0V, TA= +25°C, unless otherwise noted. RFIN and IFOUT matched to 50Ω. PLO = -5dBm,
PRFIN = -25dBm.)
fLO = 1880MHz
fLO = 1880MHz
dBm
50Ωsource impedance
-27
CONDITIONS
LO Leakage at RFIN Port
dBm-23LO Leakage at IFOUT Port
fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4) dBm-61IF/2 Spurious Response
1.5:1LO Input VSWR
UNITSMIN TYP MAXPARAMETER
Note 1: Guaranteed by design and characterization.
Note 2: Operation outside of this specification is possible, but performance is not characterized and is not guaranteed.
Note 3: Two input tones at -25dBm per tone.
Note 4: This spurious response is caused by a higher-order mixing product (2x2). Specified RF frequency is applied and IF output
power is observed at the desired IF frequency (70MHz).
Typical Operating Characteristics
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA= +25°C, unless otherwise noted.)
MAX2680/MAX2681/MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
_______________________________________________________________________________________ 5
0
0.03
0.02
0.01
0.04
0.05
0.06
0.07
0.08
0.09
0.10
2.5 3.53.0 4.0 4.5 5.0 5.5
MAX2680
SHUTDOWN SUPPLY
CURRENT vs. SUPPLY VOLTAGE
MAX2680/1/2-04
SUPPLY VOLTAGE (V)
SHUTDOWN SUPPLY CURRENT (µA)
TA = +85°C
TA = +25°C
TA = -40°C
SHDN = GND
-1
5
3
1
7
9
11
13
15
-14 -10 -8-12 -6 -4 -2 0
MAX2680
CONVERSION POWER GAIN vs. LO POWER
MAX2680/1/2-07
LO POWER (dBm)
CONVERSION POWER GAIN (dB)
fRF
900MHz
1950MHz
2450MHz
fLO
970MHz
1880MHz
2210MHz
fIF
70MHz
70MHz
240MHz
fRF = 900MHz
fRF = 2450MHz
fRF = 1950MHz
0
0.03
0.02
0.01
0.04
0.05
0.06
0.07
0.08
0.09
0.10
2.5 3.53.0 4.0 4.5 5.0 5.5
MAX2681
SHUTDOWN SUPPLY
CURRENT vs. SUPPLY VOLTAGE
MAX2680/1/2-05
SUPPLY VOLTAGE (V)
SHUTDOWN SUPPLY CURRENT (µA)
TA = +85°C
TA = +25°C
TA = -40°C
SHDN = GND
0
0.03
0.02
0.01
0.04
0.05
0.06
0.07
0.08
0.09
0.10
2.5 3.53.0 4.0 4.5 5.0 5.5
MAX2682
SHUTDOWN SUPPLY
CURRENT vs. SUPPLY VOLTAGE
MAX2680/1/2-06
SUPPLY VOLTAGE (V)
SHUTDOWN SUPPLY CURRENT (µA)
TA = +85°C
TA = +25°C
TA = -40°C
SHDN = GND
0
6
4
2
8
10
12
14
16
-14 -10 -8-12 -6 -4 -2 0
MAX2681
CONVERSION POWER GAIN vs. LO POWER
MAX2680/1/2-08
LO POWER (dBm)
CONVERSION POWER GAIN (dB)
fRF = 900MHz
fRF = 1950MHz
fRF = 2450MHz
fRF
900MHz
1950MHz
2450MHz
fLO
970MHz
1880MHz
2210MHz
fIF
70MHz
70MHz
240MHz
0
6
4
2
8
10
12
14
16
-14 -10 -8-12 -6 -4 -2 0
MAX2682
CONVERSION POWER GAIN vs. LO POWER
MAX2680/1/2-09
LO POWER (dBm)
CONVERSION POWER GAIN (dB)
fRF = 900MHz
fRF = 1950MHz
fRF = 2450MHz
fRF
900MHz
1950MHz
2450MHz
fLO
970MHz
1880MHz
2210MHz
fIF
70MHz
70MHz
240MHz
Typical Operating Characteristics (continued)
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA= +25°C, unless otherwise noted.)
0
6
4
2
8
10
12
14
16
-40 0 20-20 40 60 80 100
MAX2680
CONVERSION POWER GAIN vs. TEMPERATURE
MAX2680/1/2-10
TEMPERATURE (°C)
CONVERSION POWER GAIN (dB)
fRF = 900MHz
fRF = 1950MHz
fRF = 2450MHz
fRF
900MHz
1950MHz
2450MHz
fLO
970MHz
1880MHz
2210MHz
fIF
70MHz
70MHz
240MHz
0
6
4
2
8
10
12
14
16
-40 0 20-20 40 60 10080
MAX2681
CONVERSION POWER GAIN vs. TEMPERATURE
MAX2680/1/2-11
TEMPERATURE (°C)
CONVERSION POWER GAIN (dB)
fRF = 900MHz
fRF = 1950MHz
fRF = 2450MHz
1
7
5
3
9
11
13
15
17
-40 0 20-20 40 60 80 100
MAX2682
CONVERSION POWER GAIN vs. TEMPERATURE
MAX2680/1/2-12
TEMPERATURE (°C)
CONVERSION POWER GAIN (dB)
fRF = 900MHz
fRF = 1950MHz
fRF = 2450MHz
MAX2680/MAX2681/MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA= +25°C, unless otherwise noted.)
-10
-8
-9
-7
-6
-5
-14 -10 -8-12 -6 -4 -2 0
MAX2680
INPUT IP3 vs. LO POWER
MAX2680/1/2-13
LO POWER (dBm)
INPUT IP3 (dBm)
fRF = 1950MHz, 1951MHz
fLO = 1880MHz
fIF = 70MHz
PRFIN = -25dBm PER TONE
-3
-1
-2
0
1
2
-14 -10 -8-12 -6 -4 -2 0
MAX2681
INPUT IP3 vs. LO POWER
MAX2680/1/2-14
LO POWER (dBm)
INPUT IP3 (dBm)
fRF = 1950MHz, 1951MHz
fLO = 1880MHz
fIF = 70MHz
PRFIN = -25dBm PER TONE
0
3
2
4
1
5
6
7
-14 -10 -8-12 -6 -4 -2 0
MAX2682
INPUT IP3 vs. LO POWER
MAX2680/1/2-15
LO POWER (dBm)
INPUT IP3 (dBm)
fRF = 1950MHz, 1951MHz
fLO = 1880MHz
fIF = 70MHz
PRFIN = -25dBm PER TONE
0
6
4
10
8
2
12
14
16
-14 -10 -8-12 -6 -4 -2 0
MAX2680
NOISE FIGURE vs. LO POWER
MAX2680/1/2-16
LO POWER (dBm)
NOISE FIGURE (dB)
fRF = 900MHz
fRF = 1950MHz
fRF = 2450MHz
fRF
900MHz
1950MHz
2450MHz
fLO
970MHz
2020MHz
2210MHz
fIF
70MHz
70MHz
70MHz
0
150
100
50
200
250
300
0 1000500 1500 2000 2500
MAX2680
RF PORT IMPEDANCE vs. RF FREQUENCY
MAX2680/1/2-19
RF FREQUENCY (MHz)
REAL IMPEDANCE (Ω)
-600
-300
-400
-500
-200
-100
0
IMAGINARY IMPEDANCE (Ω)
IMAGINARY
REAL
fLO = 970MHz
PLO = -5dBm
0
8
6
14
12
10
2
4
16
18
20
-14 -10 -8-12 -6 -4 -2 0
MAX2681
NOISE FIGURE vs. LO POWER
MAX2680/1/2-17
LO POWER (dBm)
NOISE FIGURE (dB)
fRF = 900MHz
fRF = 1950MHz
fRF = 2450MHz
fRF
900MHz
1950MHz
2450MHz
fLO
970MHz
2020MHz
2210MHz
fIF
70MHz
70MHz
70MHz
0
10
5
15
20
25
-14 -10 -8-12 -6 -4 -2 0
MAX2682
NOISE FIGURE vs. LO POWER
MAX2680/1/2-18
LO POWER (dBm)
NOISE FIGURE (dB)
fRF = 900MHz
fRF = 1950MHz
fRF = 2450MHz
fRF
900MHz
1950MHz
2450MHz
fLO
970MHz
2020MHz
2210MHz
fIF
70MHz
70MHz
70MHz
0
150
100
50
200
250
300
0 500 1000 1500 2000 2500
MAX2681
RF PORT IMPEDANCE vs. RF FREQUENCY
MAX2680/1/2-20
RF FREQUENCY (MHz)
REAL IMPEDANCE (Ω)
IMAGINARY
REAL
fLO = 970MHz
PLO = -5dBm
-600
-300
-400
-500
-200
-100
0
IMAGINARY IMPEDANCE (Ω)
0
150
100
50
200
250
300
0 1000500 1500 2000 2500
MAX2682
RF PORT IMPEDANCE vs. RF FREQUENCY
MAX2680/1/2-21
RF FREQUENCY (MHz)
REAL IMPEDANCE (Ω)
-600
-300
-400
-500
-200
-100
0
IMAGINARY IMPEDANCE (Ω)
IMAGINARY
REAL
fLO = 970MHz
PLO = -5dBm
MAX2680/MAX2681/MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
_______________________________________________________________________________________ 7
0
600
400
200
800
1000
1200
0 200100 300 400 500
MAX2680
IF PORT IMPEDANCE vs. IF FREQUENCY
MAX2680/1/2-22
IF FREQUENCY (MHz)
REAL IMPEDANCE (Ω)
-600
-300
-400
-500
-200
-100
0
IMAGINARY IMPEDANCE (Ω)
IMAGINARY
REAL
fLO = 970MHz
PLO = -5dBm
0
600
400
200
800
1000
1200
0 200100 300 400 500
MAX2681
IF PORT IMPEDANCE vs. IF FREQUENCY
MAX2680/1/2-23
IF FREQUENCY (MHz)
REAL IMPEDANCE (Ω)
-600
-300
-400
-500
-200
-100
0
IMAGINARY IMPEDANCE (Ω)
IMAGINARY
REAL
fLO = 970MHz
PLO = -5dBm
0
300
200
100
500
400
600
700
800
0 200100 300 400 500
MAX2682
IF PORT IMPEDANCE vs. IF FREQUENCY
MAX2680/1/2-24
IF FREQUENCY (MHz)
REAL IMPEDANCE (Ω)
-400
-350
-250
-200
-300
-150
-50
-100
0
IMAGINARY IMPEDANCE (Ω)
IMAGINARY
REAL
fLO = 970MHz
PLO = -5dBm
-40
-30
-35
-20
-25
-10
-15
-5
+5
0
+10
200 760 1320 1880 2440 3000
MAX2680
LO PORT RETURN LOSS
MAX2680/1/2-25
FREQUENCY (MHz)
RETURN LOSS (dB)
0
10
5
20
15
30
25
35
0 1000500 1500 2000 2500
MAX2680
LO-to-IF AND LO-to-RF ISOLATION
MAX2680/1/2-28
LO FREQUENCY (MHz)
ISOLATION (dB)
LO-to-IF ISOLATION
LO-to-RF ISOLATION
-40
-30
-35
-20
-25
-10
-15
-5
+5
0
+10
200 760 1320 1880 2440 3000
MAX2681
LO PORT RETURN LOSS
MAX2680/1/2-26
FREQUENCY (MHz)
RETURN LOSS (dB)
-40
-30
-35
-20
-25
-10
-15
-5
+5
0
+10
200 760 1320 1880 2440 3000
MAX2682
LO PORT RETURN LOSS
MAX2680/1/2-27
FREQUENCY (MHz)
RETURN LOSS (dB)
0
10
5
25
20
15
35
30
40
0 1000500 1500 2000 2500
MAX2681
LO-to-IF AND LO-to-RF ISOLATION
MAX2680/1/2-29
LO FREQUENCY (MHz)
ISOLATION (dB)
LO-to-IF ISOLATION
LO-to-RF ISOLATION
10
15
25
20
30
35
0 1000500 1500 2000 2500
MAX2682
LO-to-IF AND LO-to-RF ISOLATION
MAX2680/1/2-30
LO FREQUENCY (MHz)
ISOLATION (dB)
LO-to-IF ISOLATION
LO-to-RF ISOLATION
Typical Operating Characteristics (continued)
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA= +25°C, unless otherwise noted.)
MAX2680/MAX2681/MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
8 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA= +25°C, unless otherwise noted.)
Pin Description
SHDN
2V/div
IFOUT
50mV/
div
500ns/div
MAX2680
TURN-OFF/ON CHARACTERISTICS
MAX2680/1/2-31
Z1 = 39pF
SHDN
2V/div
IFOUT
50mV/
div
500ns/div
MAX2681
TURN-OFF/ON CHARACTERISTICS
MAX2680/1/2-32
Z1 = 39pF
SHDN
2V/div
IFOUT
50mV/
div
500ns/div
MAX2682
TURN-OFF/ON CHARACTERISTICS
MAX2680/1/2-33
Z2 = 39pF
PIN
Local-Oscillator Input. Apply a local-oscillator signal with an amplitude of -10dBm to 0 (50Ωsource). AC-
couple this pin to the oscillator with a DC-blocking capacitor. Nominal DC voltage is VCC - 0.4V.
LO1
FUNCTIONNAME
Mixer Ground. Connect to the ground plane with a low-inductance connection.GND2
Intermediate Frequency Output. Open-collector output requires an inductor to VCC. AC-couple to this pin
with a DC-blocking capacitor. See Applications Information section for details on impedance matching.
IFOUT4
Radio Frequency Input. AC-couple to this pin with a DC-blocking capacitor. Nominal DC voltage is 1.5V.
See Applications Information section for details on impedance matching.
RFIN3
Supply Voltage Input, +2.7V to +5.5V. Bypass with a capacitor to the ground plane. Capacitor value
depends upon desired operating frequency.
VCC
5
Active-Low Shutdown. Drive low to disable all device functions and reduce the supply current to less than
5µA. For normal operation, drive high or connect to VCC.
SHDN
6
Detailed Description
The MAX2680/MAX2681/MAX2682 are 400MHz to
2.5GHz, silicon-germanium, double-balanced down-
converter mixers. They are designed to provide opti-
mum linearity performance for a specified supply
current. They consist of a double-balanced Gilbert-cell
mixer with single-ended RF, LO, and IF port connec-
tions. An on-chip bias cell provides a low-power shut-
down feature. Consult the Selector Guide for device
features and comparison.
Applications Information
Local-Oscillator (LO) Input
The LO input is a single-ended broadband port with a
typical input VSWR of better than 2.0:1 from 400MHz to
2.5GHz. The LO signal is mixed with the RF input sig-
nal, and the resulting downconverted output appears at
IFOUT. AC-couple LO with a capacitor. Drive the LO
port with a signal ranging from -10dBm to 0 (50Ω
source).
RF Input
The RF input frequency range is 400MHz to 2.5GHz.
The RF input requires an impedance-matching network
as well as a DC-blocking capacitor that can be part of
the matching network. Consult Tables 1 and 2, as well
as the RF Port Impedance vs. RF Frequency graph in
the Typical Operating Characteristics for information on
matching.
IF Output
The IF output frequency range extends from 10MHz to
500MHz. IFOUT is a high-impedance, open-collector
output that requires an external inductor to VCC for
proper biasing. For optimum performance, the IF port
requires an impedance-matching network. The configu-
ration and values for the matching network is depen-
dent upon the frequency and desired output
impedance. For assistance in choosing components for
optimal performance, refer to Tables 3 and 4 as well as
the IF Port Impedance vs. IF Frequency graph in the
Typical Operating Characteristics.
Power-Supply and
SSHHDDNN
Bypassing
Proper attention to voltage supply bypassing is essen-
tial for high-frequency RF circuit stability. Bypass VCC
with a 10µF capacitor in parallel with a 1000pF capaci-
tor. Use separate vias to the ground plane for each of
the bypass capacitors and minimize trace length to
reduce inductance. Use separate vias to the ground
plane for each ground pin. Use low-inductance ground
connections.
Decouple SHDN with a 1000pF capacitor to ground to
minimize noise on the internal bias cell. Use a series
resistor (typically 100Ω) to reduce coupling of high-fre-
quency signals into the SHDN pin.
Layout Issues
A well designed PC board is an essential part of an RF
circuit. For best performance, pay attention to power-
supply issues as well as to the layout of the RFIN and
IFOUT impedance-matching network.
MAX2680/MAX2681/MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
_______________________________________________________________________________________ 9
179-j356MAX2680
Table 1. RFIN Port Impedance
54-j179 32-j94 33-j73
FREQUENCY
75-j188209-j332MAX2681 34-j108 33-j86
78-j182206-j306MAX2682 34-j106 29-j86
Table 2. RF Input Impedance-Matching Component Values
270pF86nHZ1 1.5pF Short
MAX2680
22nH270pFZ2 270pF 270pF
OpenOpenZ3 1.8nH 1.8nH
Note: Z1, Z2, and Z3 are found in the Typical Operating Circuit.
270pF68nH 1.5pF Short
MAX2681
18nH270pF 270pF 270pF
Open0.5pF 1.8nH 2.2nH
1.5pF68nH Short Short
MAX2682
270pF270pF 270pF 270pF
10nH0.5pF 2.2nH 1.2nH
900
MHz
1950
MHz
2450
MHz
900
MHz
1950
MHz
2450
MHz
400
MHz
900
MHz
1950
MHz
400
MHz
2450
MHz
400
MHz
900MHz 1950MHz 2450MHz
PART
400MHz
FREQUENCY
MATCHING
COMPONENTS
MAX2680/MAX2681/MAX2682
Power-Supply Layout
To minimize coupling between different sections of the
IC, the ideal power-supply layout is a star configuration
with a large decoupling capacitor at a central VCC
node. The VCC traces branch out from this central
node, each going to a separate VCC node on the PC
board. At the end of each trace is a bypass capacitor
that has low ESR at the RF frequency of operation. This
arrangement provides local decoupling at the VCC pin.
At high frequencies, any signal leaking out of one sup-
ply pin sees a relatively high impedance (formed by the
VCC trace inductance) to the central VCC node, and an
even higher impedance to any other supply pin, as well
as a low impedance to ground through the bypass
capacitor.
Impedance-Matching Network Layout
The RFIN and IFOUT impedance-matching networks are
very sensitive to layout-related parasitics. To minimize
parasitic inductance, keep all traces short and place
components as close as possible to the chip. To mini-
mize parasitic capacitance, use cutouts in the ground
plane (and any other plane) below the matching network
components. However, avoid cutouts that are larger
than necessary since they act as aperture antennas.
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
10 ______________________________________________________________________________________
Table 3. IFOUT Port Impedance
803-j785960-j372MAX2680 186-j397
FREQUENCY
746-j526934-j373MAX2681 161-j375
578-j299670-j216MAX2682 175-j296
Table 4. IF Output Impedance-Matching
Components
330nH390nHL1 82nH
FREQUENCY
15pF39pFC2 3pF
Open250ΩR1 Open
70MHz 240MHz
PART
45MHz
70MHz 240MHz
MATCHING
COMPONENT 45MHz
MAX2680
MAX2681
MAX2682
LO
C3
6
5
4
SHUTDOWN
CONTROL
1SHDN
VCC
RF
INPUT
LO
INPUT
C1
IFOUT
2
Z2
Z3
Z13
GND
RFIN
THE VALUES OF MATCHING COMPONENTS C2, L1, R1, Z1, Z2, AND Z3 DEPEND ON THE IF AND RF FREQUENCY AND DOWNCONVERTER. SEE TABLES 2 AND 4.
VCC
+2.7V TO +5.5V
IF
OUTPUT
L1
C2
R1
C4
1000pF
C5
10µF
Typical Operating Circuit
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 11
© 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
6LSOT.EPS
F1
1
21-0058
PACKAGE OUTLINE, SOT-23, 6L
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.)
