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 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 perfor-
mance. 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
●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
19-4786; Rev 2; 8/03
Typical Operating Circuit appears at end of data sheet.
PART TEMP RANGE PIN-
PACKAGE
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
PART ICC
(mA)
FREQUENCY
900MHz 1950MHz 2450MHz
IIP3
(dBm)
NF
(dB)
GAIN
(dB)
IIP3
(dBm)
NF
(dB)
GAIN
(dB)
IIP3
(dBm)
NF
(dB)
GAIN
(dB)
MAX2680 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
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Selector Guide
Ordering Information
EVALUATION KIT AVAILABLE
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
(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.)
(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 TYP MAX UNITS
Operating Supply Current ICC
MAX2680 5.0 7.7
mAMAX2681 8.7 12.7
MAX2682 15.0 21.8
Shutdown Supply Current ICC SHDN = 0.5V 0.05 μA
Shutdown Input Voltage High VIH 2.0 V
Shutdown Input Voltage Low VIL 0.5 V
Shutdown Input Bias Current ISHDN 0 < SHDN < VCC 0.2 μA
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
Conversion Power Gain
fRF = 400MHz, fLO = 445MHz, fIF = 45MHz 7.3
dB
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz 11.6
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1) 5.7 7.6 8.6
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 7.0
Gain Variation Over Temperature fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz,
TA = TMIN to TMAX (Note 1) 1.9 2.4 dB
Input Third-Order Intercept Point
(Note 3)
fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz -12.9
dBmfRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz -8.2
fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz -6.9
Noise Figure (Single Sideband)
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz 6.3
dBfRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz 8.3
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 11.7
LO Input VSWR 50Ω source impedance 1.5:1
LO Leakage at IFOUT Port fLO = 1880MHz -22 dBm
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
www.maximintegrated.com Maxim Integrated
│
2
Absolute Maximum Ratings
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.
AC Electrical Characteristics
DC Electrical Characteristics
CAUTION!
ESD SENSITIVE DEVICE
(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 Leakage at RFIN Port fLO = 1880MHz -26 dBm
IF/2 Spurious Response fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4) -51 dBm
MAX2681
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
Conversion Power Gain
fRF = 400MHz, fLO = 445MHz, fIF = 45MHz 11.0
dB
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz 14.2
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1) 6.7 8.4 9.4
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 7.7
Gain Variation Over Temperature fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz,
TA = TMIN to TMAX (Note 1) 1.7 2.3 dB
Input Third-Order Intercept Point
(Note 3)
fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz -6.1
dBmfRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz +0.5
fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz +1.0
Noise Figure (Single Sideband)
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz 7.0
dBfRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz 11.1
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 12.7
LO Input VSWR 50Ω source impedance 1.5:1
LO Leakage at IFOUT Port fLO = 1880MHz -23 dBm
LO Leakage at RFIN Port fLO = 1880MHz -27 dBm
IF/2 Spurious Response fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4) -65 dBm
MAX2682
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
Conversion Power Gain
fRF = 400MHz, fLO = 445MHz, fIF = 45MHz 13.4
dB
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz 14.7
fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1) 8.7 10.4 11.7
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 7.9
Gain Variation Over Temperature fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz,
TA = TMIN to TMAX (Note 1) 2.1 3.2 dB
Input Third-Order Intercept Point
(Note 3)
fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz -1.8
dBmfRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz +4.4
fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz +3.2
Noise Figure (Single Sideband)
fRF = 900MHz, fLO = 970MHz, fIF = 70MHz 6.5
dBfRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz 10.2
fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 13.4
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
www.maximintegrated.com Maxim Integrated
│
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.)
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 Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.)
PARAMETER CONDITIONS MIN TYP MAX UNITS
LO Input VSWR 50Ω source impedance 1.5:1
LO Leakage at IFOUT Port fLO = 1880MHz -23 dBm
LO Leakage at RFIN Port fLO = 1880MHz -27 dBm
IF/2 Spurious Response fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4) -61 dBm
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°C TA = -40°C
SHDN = VCC
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
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
www.maximintegrated.com Maxim Integrated
│
4
AC Electrical Characteristics (continued)
Typical Operating Characteristics
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.)
-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
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
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
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
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
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Maxim Integrated
│
5
www.maximintegrated.com
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
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 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 (W)
IMAGINARY
REAL
fLO = 970MHz
PLO = -5dBm
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
Maxim Integrated
│
6
www.maximintegrated.com
Typical Operating Characteristics (continued)
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.)
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)
-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
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
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
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
Maxim Integrated
│
7
www.maximintegrated.com
Typical Operating Characteristics (continued)
(Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.)
PIN NAME FUNCTION
1 LO 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.
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 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.
5 VCC
Supply Voltage Input, +2.7V to +5.5V. Bypass with a capacitor to the ground plane. Capacitor value depends
upon desired operating frequency.
6SHDN 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
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
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
www.maximintegrated.com Maxim Integrated
│
8
Pin Description
Typical Operating Characteristics (continued)
GND
IFOUTRFIN
1 6 SHDN
5 VCC
LO
MAX2680
MAX2681
MAX2682
SOT23-6
TOP VIEW
2
3 4
Pin Conguration
Detailed Description
The MAX2680/MAX2681/MAX2682 are 400MHz to
2.5GHz, silicon-germanium, double-balanced downcon-
verter 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 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 section 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 imped-
ance-matching network. The configuration and values for
the matching network is dependent upon the frequency and
desired output impedance. For assistance in choosing com-
ponents 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 induc-
tance. 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.
Table 1. RFIN Port Impedance
Table 2. RF Input Impedance-Matching Component Values
Note: Z1, Z2, and Z3 are found in the Typical Operating Circuit.
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
MATCHING
COMPONENTS
FREQUENCY
MAX2680 MAX2681 MAX2682
400
MHz
900
MHz
1950
MHz
2450
MHz
400
MHz
900
MHz
1950
MHz
2450
MHz
400
MHz
900
MHz
1950
MHz
2450
MHz
Z1 86nH 270pF 1.5pF Short 68nH 270pF 1.5pF Short 68nH 1.5pF Short Short
Z2 270pF 22nH 270pF 270pF 270pF 18nH 270pF 270pF 270pF 270pF 270pF 270pF
Z3 Open Open 1.8nH 1.8nH 0.5pF Open 1.8nH 2.2nH 0.5pF 10nH 2.2nH 1.2nH
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
www.maximintegrated.com Maxim Integrated
│
9
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.
Impedance-Matching Network Layout
The RFIN and IFOUT impedance-matching networks
are very sensitive to layout-related parasitics. To mini-
mize 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.
Table 3. IFOUT Port Impedance
Table 4. IF Output Impedance-Matching
Components
PART 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
MATCHING
COMPONENT
FREQUENCY
45MHz 70MHz 240MHz
L1 390nH 330nH 82nH
C2 39pF 15pF 3pF
R1 250Ω Open Open
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
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
www.maximintegrated.com Maxim Integrated
│
10
Typical Operating Circuit
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
www.maximintegrated.com Maxim Integrated
│
11
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.
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 specications 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.
MAX2680/MAX2681/
MAX2682
400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers
© 2003 Maxim Integrated Products, Inc.
│
12
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.
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Maxim Integrated:
MAX2680EUT-T MAX2681EUT-T MAX2680AUT+T MAX2680EUT+T MAX2681EUT+T