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EVALUATION KIT AVAILABLE
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
General Description
The MAX2680/MAX2681/MAX2682 miniature, low-cost,
low-noise downconverter mixers are designed for lowvoltage operation and are ideal for use in portable communications 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 single
+2.7V to +5.5V supply, allowing them to be powered
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 current.
The MAX2680/MAX2681/MAX2682 are manufactured on
a high-frequency, low-noise, advanced silicon-germanium
process and are offered in the space-saving 6-pin SOT23
package.
Applications
●●
●●
●●
●●
●●
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
Ordering Information
400MHz/900MHz/2.4GHz ISM-Band Radios
Personal Communications Systems (PCS)
Cellular and Cordless Phones
Wireless Local Loop
IEEE-802.11 and Wireless Data
PART
TEMP RANGE
PINPACKAGE
SOT
TOP MARK
MAX2680EUT-T
-40°C to +85°C
6 SOT23
AAAR
MAX2681EUT-T
-40°C to +85°C
6 SOT23
AAAS
MAX2682EUT-T
-40°C to +85°C
6 SOT23
AAAT
Selector Guide
FREQUENCY
PART
ICC
(mA)
MAX2680
900MHz
1950MHz
2450MHz
IIP3
(dBm)
NF
(dB)
GAIN
(dB)
IIP3
(dBm)
NF
(dB)
GAIN
(dB)
IIP3
(dBm)
NF
(dB)
GAIN
(dB)
5.0
-12.9
6.3
11.6
-8.2
8.3
7.6
-6.9
11.7
7.0
MAX2681
8.7
-6.1
7.0
14.2
+0.5
11.1
8.4
+1.0
12.7
7.7
MAX2682
15.0
-1.8
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.
19-4786; Rev 2; 8/03
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Absolute Maximum Ratings
VCC to GND..........................................................-0.3V to +6.0V
RFIN Input Power (50Ω source)......................................+10dBm
LO Input Power (50Ω source).........................................+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 (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
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.
CAUTION! ESD SENSITIVE DEVICE
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.)
PARAMETER
SYMBOL
CONDITIONS
MIN
MAX2680
Operating Supply Current
Shutdown Supply Current
Shutdown Input Voltage High
Shutdown Input Voltage Low
Shutdown Input Bias Current
TYP
MAX
5.0
7.7
ICC
MAX2681
8.7
12.7
MAX2682
15.0
21.8
ICC
SHDN = 0.5V
VIH
VIL
ISHDN
0.05
mA
μA
2.0
V
0.5
0 < SHDN < VCC
UNITS
0.2
V
μA
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.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
MAX2680
RF Frequency Range
(Notes 1, 2)
400
2500
MHz
LO Frequency Range
(Notes 1, 2)
400
2500
MHz
IF Frequency Range
(Notes 1, 2)
10
500
MHz
fRF = 400MHz, fLO = 445MHz, fIF = 45MHz
Conversion Power Gain
Gain Variation Over Temperature
Input Third-Order Intercept Point
(Note 3)
Noise Figure (Single Sideband)
LO Input VSWR
LO Leakage at IFOUT Port
www.maximintegrated.com
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1)
7.3
11.6
5.7
7.6
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
7.0
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz,
TA = TMIN to TMAX (Note 1)
1.9
fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz
-12.9
fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz
-6.9
fRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz
8.3
fRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz
-8.2
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
6.3
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
50Ω source impedance
fLO = 1880MHz
8.6
2.4
dB
dB
dBm
dB
11.7
1.5:1
-22
dBm
Maxim Integrated │ 2
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
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.)
PARAMETER
LO Leakage at RFIN Port
IF/2 Spurious Response
MAX2681
CONDITIONS
MIN
fLO = 1880MHz
fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4)
TYP
MAX
UNITS
-26
dBm
-51
dBm
RF Frequency Range
(Notes 1, 2)
400
2500
MHz
LO Frequency Range
(Notes 1, 2)
400
2500
MHz
IF Frequency Range
(Notes 1, 2)
10
500
MHz
fRF = 400MHz, fLO = 445MHz, fIF = 45MHz
Conversion Power Gain
Gain Variation Over Temperature
Input Third-Order Intercept Point
(Note 3)
Noise Figure (Single Sideband)
LO Input VSWR
LO Leakage at IFOUT Port
LO Leakage at RFIN Port
IF/2 Spurious Response
MAX2682
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1)
11.0
14.2
6.7
8.4
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
7.7
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz,
TA = TMIN to TMAX (Note 1)
1.7
fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz
-6.1
fRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz
9.4
2.3
+0.5
fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz
+1.0
fRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz
11.1
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
dB
dB
dBm
7.0
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
dB
12.7
50Ω source impedance
1.5:1
fLO = 1880MHz
-23
dBm
-27
dBm
fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4)
-65
dBm
fLO = 1880MHz
RF Frequency Range
(Notes 1, 2)
400
2500
MHz
LO Frequency Range
(Notes 1, 2)
400
2500
MHz
IF Frequency Range
(Notes 1, 2)
10
500
MHz
fRF = 400MHz, fLO = 445MHz, fIF = 45MHz
Conversion Power Gain
Gain Variation Over Temperature
Input Third-Order Intercept Point
(Note 3)
Noise Figure (Single Sideband)
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1)
14.7
8.7
10.4
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
7.9
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz,
TA = TMIN to TMAX (Note 1)
2.1
fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz
fRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz
+3.2
fRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz
10.2
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz
11.7
3.2
dB
dB
-1.8
+4.4
fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz
www.maximintegrated.com
13.4
dBm
6.5
dB
13.4
Maxim Integrated │ 3
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
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.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
LO Input VSWR
50Ω source impedance
LO Leakage at IFOUT Port
fLO = 1880MHz
-23
dBm
-27
dBm
fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4)
-61
dBm
LO Leakage at RFIN Port
fLO = 1880MHz
IF/2 Spurious Response
Note
Note
Note
Note
1.5:1
1: Guaranteed by design and characterization.
2: Operation outside of this specification is possible, but performance is not characterized and is not guaranteed.
3: Two input tones at -25dBm per tone.
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.)
TA = +85°C
TA = +25°C
5
4
TA = -40°C
TA = +85°C
9
8
TA = +25°C
TA = -40°C
7
3
6
2
5
18
MAX2682
SUPPLY CURRENT vs. SUPPLY VOLTAGE
17
SHDN = VCC
TA = +85°C
16
MAX2680/1/2-03
SHDN = VCC
SUPPLY CURRENT (mA)
6
10
MAX2680/1/2-01
SHDN = VCC
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
7
MAX2681
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2680/1/2-02
MAX2680
SUPPLY CURRENT vs. SUPPLY VOLTAGE
15
14
13
TA = +25°C
TA = -40°C
12
11
10
9
2.5
3.0
3.5
4.0
4.5
SUPPLY VOLTAGE (V)
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5.0
5.5
2.5
3.0
3.5
4.0
4.5
SUPPLY VOLTAGE (V)
5.0
5.5
8
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
Maxim Integrated │ 4
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Typical Operating Characteristics (continued)
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.)
TA = +85°C
TA = +25°C
0.06
0.05
0.04
TA = -40°C
0.03
0.02
0.01
0
2.5
3.0
3.5
4.0
4.5
5.0
TA = +25°C
0.06
TA = +85°C
0.05
0.04
TA = -40°C
0.03
0.02
0.01
2.5
3.0
3.5
4.0
4.5
5.0
SHDN = GND
0.09
0.08
0.07
TA = +85°C
TA = +25°C
0.06
0.05
0.04
0.03
TA = -40°C
0.02
0.01
0
5.5
MAX2680/1/2-06
0.10
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
MAX2680
CONVERSION POWER GAIN vs. LO POWER
MAX2681
CONVERSION POWER GAIN vs. LO POWER
MAX2682
CONVERSION POWER GAIN vs. LO POWER
9
fRF = 2450MHz
fRF = 1950MHz
7
5
fRF
fIF
fLO
900MHz 970MHz 70MHz
1950MHz 1880MHz 70MHz
2450MHz 2210MHz 240MHz
3
1
-1
-14
-12
-10
-8
-6
-4
-2
10
fRF = 1950MHz
8
fRF = 2450MHz
6
fRF
fIF
fLO
900MHz 970MHz 70MHz
1950MHz 1880MHz 70MHz
2450MHz 2210MHz 240MHz
4
2
-14
-12
-10
-8
-6
-4
-2
fRF = 900MHz
14
12
fRF = 1950MHz
10
8
fRF = 2450MHz
6
fRF
fIF
fLO
900MHz 970MHz 70MHz
1950MHz 1880MHz 70MHz
2450MHz 2210MHz 240MHz
4
2
0
0
MAX2680/1/2-09
12
0
0
fRF = 900MHz
14
16
CONVERSION POWER GAIN (dB)
11
MAX2680/1/2-08
fRF = 900MHz
13
16
CONVERSION POWER GAIN (dB)
MAX2680/1/2-07
-14
-12
-10
-8
-6
-4
-2
0
LO POWER (dBm)
LO POWER (dBm)
MAX2680
CONVERSION POWER GAIN vs. TEMPERATURE
MAX2681
CONVERSION POWER GAIN vs. TEMPERATURE
MAX2682
CONVERSION POWER GAIN vs. TEMPERATURE
fRF = 900MHz
12
10
fRF = 1950MHz
8
fRF = 2450MHz
6
fRF
fIF
fLO
900MHz 970MHz 70MHz
1950MHz 1880MHz 70MHz
2450MHz 2210MHz 240MHz
4
2
0
-40
-20
0
20
40
60
TEMPERATURE (°C)
www.maximintegrated.com
80
100
16
fRF = 900MHz
14
12
10
fRF = 1950MHz
8
fRF = 2450MHz
6
4
2
0
-40
-20
0
20
40
60
TEMPERATURE (°C)
80
100
17
CONVERSION POWER GAIN (dB)
14
MAX2680/1/2-10
16
fRF = 900MHz
15
13
MAX2680/1/2-12
LO POWER (dBm)
MAX2680/1/2-11
CONVERSION POWER GAIN (dB)
0.07
MAX2682
SHUTDOWN SUPPLY
CURRENT vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
15
CONVERSION POWER GAIN (dB)
0.08
0
5.5
SHDN = GND
0.09
SHUTDOWN SUPPLY CURRENT (µA)
0.07
MAX2680/1/2-05
0.08
MAX2681
SHUTDOWN SUPPLY
CURRENT vs. SUPPLY VOLTAGE
0.10
SHUTDOWN SUPPLY CURRENT (µA)
SHDN = GND
0.09
CONVERSION POWER GAIN (dB)
SHUTDOWN SUPPLY CURRENT (µA)
0.10
MAX2680/1/2-04
MAX2680
SHUTDOWN SUPPLY
CURRENT vs. SUPPLY VOLTAGE
fRF = 1950MHz
11
9
7
fRF = 2450MHz
5
3
1
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
Maxim Integrated │ 5
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Typical Operating Characteristics (continued)
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.)
-9
16
-12
-10
-8
-6
-10
-8
MAX2680/1/2-15
MAX2680/1/2-14
-12
-6
-4
-2
0
0
-14
-12
-10
-8
-6
-4
-2
MAX2680
NOISE FIGURE vs. LO POWER
MAX2681
NOISE FIGURE vs. LO POWER
MAX2682
NOISE FIGURE vs. LO POWER
20
18
16
NOISE FIGURE (dB)
fRF = 2450MHz
12
fRF = 1950MHz
10
8
fRF = 900MHz
6
fRF
fIF
fLO
900MHz 970MHz 70MHz
1950MHz 2020MHz 70MHz
2450MHz 2210MHz 70MHz
2
-14
-14
LO POWER (dBm)
-12
-10
-8
-6
-4
-2
14
fRF = 2450MHz
12
fRF = 1950MHz
10
8
fRF = 900MHz
6
2
0
0
25
-14
-12
-10
-8
-6
0
fRF
fIF
fLO
900MHz 970MHz 70MHz
1950MHz 2020MHz 70MHz
2450MHz 2210MHz 70MHz
20
fRF
fIF
fLO
900MHz 970MHz 70MHz
1950MHz 2020MHz 70MHz
2450MHz 2210MHz 70MHz
4
15
fRF = 2450MHz
fRF = 1950MHz
10
fRF = 900MHz
5
-4
-2
0
0
-14
-12
-10
-8
-6
-4
-2
0
LO POWER (dBm)
LO POWER (dBm)
LO POWER (dBm)
MAX2680
RF PORT IMPEDANCE vs. RF FREQUENCY
MAX2681
RF PORT IMPEDANCE vs. RF FREQUENCY
MAX2682
RF PORT IMPEDANCE vs. RF FREQUENCY
250
300
-100
250
200
-200
150
-300
100
-400
50
0
REAL
fLO = 970MHz
PLO = -5dBm
0
500
1000
1500
RF FREQUENCY (MHz)
www.maximintegrated.com
-500
2000
-600
2500
MAX2680/1/2-20
IMAGINARY
0
300
-100
250
200
-200
150
-300
100
-400
50
0
fLO = 970MHz
PLO = -5dBm
0
500
1000
1500
REAL
-500
2000
-600
2500
RF FREQUENCY (MHz)
REAL IMPEDANCE (Ω)
IMAGINARY
0
IMAGINARY IMPEDANCE (Ω)
MAX2680/1/2-19
REAL IMPEDANCE (Ω)
300
IMAGINARY IMPEDANCE (W)
NOISE FIGURE (dB)
-3
0
LO POWER (dBm)
4
REAL IMPEDANCE (Ω)
-2
LO POWER (dBm)
14
0
-4
3
1
NOISE FIGURE (dB)
-14
4
2
fRF = 1950MHz, 1951MHz
fLO = 1880MHz
fIF = 70MHz
PRFIN = -25dBm PER TONE
-2
MAX2680/1/2-16
-10
-1
5
MAX2680/1/2-21
IMAGINARY
0
-100
200
-200
150
-300
100
-400
50
0
REAL
fLO = 970MHz
PLO = -5dBm
0
500
1000
1500
2000
-500
-600
2500
RF FREQUENCY (MHz)
Maxim Integrated │ 6
IMAGINARY IMPEDANCE (Ω)
-8
0
fRF = 1950MHz, 1951MHz
fLO = 1880MHz
fIF = 70MHz
PRFIN = -25dBm PER TONE
6
INPUT IP3 (dBm)
-7
MAX2682
INPUT IP3 vs. LO POWER
7
MAX2680/1/2-17
INPUT IP3 (dBm)
1
INPUT IP3 (dBm)
fRF = 1950MHz, 1951MHz
fLO = 1880MHz
fIF = 70MHz
PRFIN = -25dBm PER TONE
-6
2
MAX2680/1/2-13
-5
MAX2681
INPUT IP3 vs. LO POWER
MAX2680/1/2-18
MAX2680
INPUT IP3 vs. LO POWER
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Typical Operating Characteristics (continued)
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.)
IMAGINARY
600
-300
400
-400
200
-500
REAL
200
300
400
500
-600
IMAGINARY
600
-300
400
-400
200
-500
REAL
0
0
100
200
300
400
500
500
400
-250
200
-300
-600
0
200
300
400
-20
-25
-5
+5
0
RETURN LOSS (dB)
-15
+10
-10
-15
-20
-25
-15
-20
-25
-30
-35
-35
-35
-40
-40
1880
2440
3000
200
760
1320
1880
2440
-40
3000
200
760
1320
1880
2440
FREQUENCY (MHz)
FREQUENCY (MHz)
FREQUENCY (MHz)
MAX2680
LO-to-IF AND LO-to-RF ISOLATION
MAX2681
LO-to-IF AND LO-to-RF ISOLATION
MAX2682
LO-to-IF AND LO-to-RF ISOLATION
35
30
ISOLATION (dB)
25
LO-to-RF ISOLATION
15
10
LO-to-IF ISOLATION
25
LO-to-RF ISOLATION
20
15
10
5
1000
1500
LO FREQUENCY (MHz)
www.maximintegrated.com
2000
2500
0
LO-to-IF ISOLATION
30
3000
25
LO-to-RF ISOLATION
20
15
5
500
35
ISOLATION (dB)
30
40
MAX2680/1/2-29
LO-to-IF ISOLATION
MAX2680/1/2-28
35
-400
-10
-30
1320
500
-5
-30
760
-350
MAX2680/1/2-27
0
RETURN LOSS (dB)
-10
0
100
MAX2682
LO PORT RETURN LOSS
0
0
0
MAX2681
LO PORT RETURN LOSS
-5
20
REAL
100
MAX2680
LO PORT RETURN LOSS
+5
-200
300
IF FREQUENCY (MHz)
+10
-150
IMAGINARY
IF FREQUENCY (MHz)
+5
200
-100
600
IF FREQUENCY (MHz)
MAX2680/1/2-25
+10
100
-200
MAX2680/1/2-24
0
fLO = 970MHz
PLO = -5dBm -50
700
MAX2680/1/2-26
0
800
-100
800
0
500
1000
1500
LO FREQUENCY (MHz)
2000
2500
10
0
500
1000
1500
2000
2500
LO FREQUENCY (MHz)
Maxim Integrated │ 7
IMAGINARY IMPEDANCE (Ω)
-200
0
MAX2682
IF PORT IMPEDANCE vs. IF FREQUENCY
MAX2680/1/2-30
1000
MAX2680/1/2-23
fLO = 970MHz
PLO = -5dBm
REAL IMPEDANCE (Ω)
-100
MAX2681
IF PORT IMPEDANCE vs. IF FREQUENCY
IMAGINARY IMPEDANCE (Ω)
800
0
RETURN LOSS (dB)
1200
REAL IMPEDANCE (Ω)
REAL IMPEDANCE (Ω)
1000
ISOLATION (dB)
0
MAX2680/1/2-22
fLO = 970MHz
PLO = -5dBm
IMAGINARY IMPEDANCE (Ω)
1200
MAX2680
IF PORT IMPEDANCE vs. IF FREQUENCY
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Typical Operating Characteristics (continued)
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.)
SHDN
2V/div
SHDN
2V/div
IFOUT
50mV/
div
IFOUT
50mV/
div
SHDN
2V/div
IFOUT
50mV/
div
Z1 = 39pF
Z1 = 39pF
MAX2682
TURN-OFF/ON CHARACTERISTICS
MAX2680/1/2-32
MAX2680/1/2-31
MAX2681
TURN-OFF/ON CHARACTERISTICS
MAX2680/1/2-33
MAX2680
TURN-OFF/ON CHARACTERISTICS
Z2 = 39pF
500ns/div
500ns/div
500ns/div
Pin Configuration
TOP VIEW
LO 1
GND 2
MAX2680
MAX2681
MAX2682
RFIN 3
6
SHDN
5
VCC
4
IFOUT
SOT23-6
Pin Description
PIN
NAME
FUNCTION
1
LO
2
GND
Mixer Ground. Connect to the ground plane with a low-inductance connection.
3
RFIN
Radio Frequency Input. AC-couple to this pin with a DC-blocking capacitor. Nominal DC voltage is 1.5V.
See the Applications Information section for details on impedance matching.
4
IFOUT
5
VCC
6
SHDN
Local-Oscillator Input. Apply a local-oscillator signal with an amplitude of -10dBm to 0 (50Ω source).
AC-couple this pin to the oscillator with a DC-blocking capacitor. Nominal DC voltage is VCC - 0.4V.
Intermediate Frequency Output. Open-collector output requires an inductor to VCC. AC-couple to this pin
with a DC-blocking capacitor. See the Applications Information section for details on impedance matching.
Supply Voltage Input, +2.7V to +5.5V. Bypass with a capacitor to the ground plane. Capacitor value depends
upon desired operating frequency.
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.
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Maxim Integrated │ 8
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Detailed Description
IF Output
The MAX2680/MAX2681/MAX2682 are 400MHz to
2.5GHz, silicon-germanium, double-balanced downconverter mixers. They are designed to provide optimum
linearity performance for a specified supply current.
They consist of a double-balanced Gilbert-cell mixer with
single-ended RF, LO, and IF port connections. An on-chip
bias cell provides a low-power shutdown 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 signal, 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 section for information
on matching.
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 configuration and values for
the matching network is dependent upon the frequency and
desired output impedance. For assistance in choosing components for optimal performance, see Table 3 and Table 4
as well as the IF Port Impedance vs. IF Frequency graph in
the Typical Operating Characteristics section.
Power-Supply and SHDN Bypassing
Proper attention to voltage supply bypassing is essential
for high-frequency RF circuit stability. Bypass VCC with a
10μF capacitor in parallel with a 1000pF capacitor. 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-frequency 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 powersupply issues as well as to the layout of the RFIN and
IFOUT impedance-matching network.
Table 1. RFIN Port Impedance
PART
FREQUENCY
400MHz
900MHz
1950MHz
2450MHz
MAX2680
179-j356
54-j179
32-j94
33-j73
MAX2681
209-j332
75-j188
34-j108
33-j86
MAX2682
206-j306
78-j182
34-j106
29-j86
Table 2. RF Input Impedance-Matching Component Values
FREQUENCY
MATCHING
COMPONENTS
MAX2680
1950
MHz
MAX2681
400
MHz
900
MHz
2450
MHz
Z1
86nH
270pF
1.5pF
Z2
270pF
22nH
270pF
Z3
Open
Open
1.8nH
1.8nH
1950
MHz
MAX2682
400
MHz
900
MHz
2450
MHz
400
MHz
900
MHz
1950
MHz
2450
MHz
Short
68nH
270pF
1.5pF
Short
68nH
1.5pF
Short
Short
270pF
270pF
18nH
270pF
270pF
270pF
270pF
270pF
270pF
0.5pF
Open
1.8nH
2.2nH
0.5pF
10nH
2.2nH
1.2nH
Note: Z1, Z2, and Z3 are found in the Typical Operating Circuit.
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Maxim Integrated │ 9
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Table 3. IFOUT Port Impedance
PART
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 supply 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.
FREQUENCY
45MHz
70MHz
240MHz
MAX2680
960-j372
803-j785
186-j397
MAX2681
934-j373
746-j526
161-j375
MAX2682
670-j216
578-j299
175-j296
Table 4. IF Output Impedance-Matching
Components
FREQUENCY
MATCHING
COMPONENT
45MHz
70MHz
240MHz
L1
390nH
330nH
82nH
C2
39pF
15pF
3pF
R1
250Ω
Open
Open
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
minimize 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.
Typical Operating Circuit
C1
LO
INPUT
1
2
SHDN
LO
C3
MAX2680
MAX2681
MAX2682
GND
6
VCC
5
L1
RF
INPUT
Z2
Z1
Z3
3
RFIN
IFOUT
SHUTDOWN
CONTROL
C4
1000pF
R1
C5
10µF
VCC
+2.7V TO +5.5V
IF
OUTPUT
4
C2
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.
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Maxim Integrated │ 10
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
www.maximintegrated.com
Maxim Integrated │ 11
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Package Information (continued)
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2003 Maxim Integrated Products, Inc. │ 12
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