MAXIM MAX2680, MAX2681, MAX2682 Technical data

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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

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

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

I

CC

(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

TOP VIEW

16SHDN

LO

GND

MAX2680

2

MAX2681
MAX2682

34

SOT23-6

5 V

IFOUTRFIN

CC

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= T

MIN

to T

MAX

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.

VCCto 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 (V

CC

+ 0.3V)

LO to GND..........................................(V

CC

- 1V) to (VCC+ 0.3V)

Continuous Power Dissipation (T

A

= +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 < V

CC

CONDITIONS

mA

15.0 21.8

I

CC

Operating Supply Current

8.7 12.7

5.0 7.7

µA0.05 5I

CC

Shutdown Supply Current

V2.0V

IH

Shutdown Input Voltage High

V0.5V

IL

Shutdown Input Voltage Low

µA0.2I

SHDN

Shutdown Input Bias Current

UNITSMIN TYP MAXSYMBOLPARAMETER

(Notes 1, 2)

(Notes 1, 2)

50Ω source 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,
P

RFIN

= -25dBm.)

fRF= 1950MHz, fLO= 1880MHz, fIF= 70MHz,
TA= T

MIN

to T

MAX

(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,
P

RFIN

= -25dBm.)

fRF= 1950MHz, fLO= 1880MHz, fIF= 70MHz,
TA= T

MIN

to T

MAX

(Note 1)

dB1.7 2.3

(Notes 1, 2)

Gain Variation Over Temperature

fLO= 1880MHz

(Notes 1, 2)

fLO= 1880MHz

dBm

50Ω source 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= T

MIN

to T

MAX

(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 = V

CC

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 = V

CC

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 = V

CC

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,
P

RFIN

= -25dBm.)

fLO= 1880MHz

fLO= 1880MHz

dBm

50Ω source 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, P

RFIN

= -25dBm, PLO= -5dBm, TA= +25°C, unless otherwise noted.)

MAX2680/MAX2681/MAX2682

400MHz to 2.5GHz, Low-Noise,

SiGe Downconverter Mixers

_______________________________________________________________________________________ 5

Typical Operating Characteristics (continued)

(Typical Operating Circuit, VCC= SHDN = +3.0V, P

RFIN

= -25dBm, PLO= -5dBm, TA= +25°C, unless otherwise noted.)

CURRENT vs. SUPPLY VOLTAGE

0.10

SHDN = GND

0.09

0.08

0.07

0.06

0.05

0.04

0.03

0.02

SHUTDOWN SUPPLY CURRENT (µA)

0.01

0

2.5 3.53.0 4.0 4.5 5.0 5.5

CONVERSION POWER GAIN vs. LO POWER

15

13

11

9

7

5

3

CONVERSION POWER GAIN (dB)

1

-1

-14 -10 -8-12 -6 -4 -2 0

MAX2680

SHUTDOWN SUPPLY

TA = +25°C

SUPPLY VOLTAGE (V)

MAX2680

fRF = 900MHz

fRF = 1950MHz

fRF = 2450MHz

f

RF

900MHz
1950MHz
2450MHz

LO POWER (dBm)

TA = -40°C

f

LO

970MHz
1880MHz
2210MHz

TA = +85°C

f

IF

70MHz
70MHz

240MHz

0.10

0.09

0.08

MAX2680/1/2-04

0.07

0.06

0.05

0.04

0.03

0.02

SHUTDOWN SUPPLY CURRENT (µA)

0.01

MAX2680/1/2-07

CONVERSION POWER GAIN (dB)

MAX2681

SHUTDOWN SUPPLY

CURRENT vs. SUPPLY VOLTAGE

SHDN = GND

TA = +25°C

0

2.5 3.53.0 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)

TA = +85°C

TA = -40°C

MAX2680/1/2-05

SHUTDOWN SUPPLY CURRENT (µA)

CURRENT vs. SUPPLY VOLTAGE

0.10
SHDN = GND

0.09

0.08

0.07

0.06

0.05

0.04

0.03

0.02

0.01

0

2.5 3.53.0 4.0 4.5 5.0 5.5

MAX2681

CONVERSION POWER GAIN vs. LO POWER

16

14

12

10

fRF = 900MHz

fRF = 1950MHz

8

6

4

2

0

-14 -10 -8-12 -6 -4 -2 0

fRF = 2450MHz

f

RF

900MHz
1950MHz
2450MHz

LO POWER (dBm)

f

LO

970MHz
1880MHz
2210MHz

70MHz
70MHz

240MHz

MAX2680/1/2-08

f

IF

CONVERSION POWER GAIN vs. LO POWER

16

14

12

10

8

6

4

CONVERSION POWER GAIN (dB)

2

0

fRF = 900MHz

-14 -10 -8-12 -6 -4 -2 0

MAX2682

SHUTDOWN SUPPLY

TA = +25°C

SUPPLY VOLTAGE (V)

MAX2682

fRF = 1950MHz

fRF = 2450MHz

f

f

RF

900MHz
1950MHz
2450MHz

LO POWER (dBm)

LO

970MHz
1880MHz
2210MHz

TA = +85°C

TA = -40°C

70MHz
70MHz

240MHz

MAX2680/1/2-06

MAX2680/1/2-09

f

IF

CONVERSION POWER GAIN vs. TEMPERATURE

MAX2680

16

14

12

10

8

fRF = 2450MHz

6

f

RF

4

CONVERSION POWER GAIN (dB)

900MHz

1950MHz

2

2450MHz

0

-40 0 20-20 40 60 80 100

fRF = 900MHz

f

f

LO

970MHz
1880MHz
2210MHz

TEMPERATURE (°C)

IF

70MHz
70MHz

240MHz

fRF = 1950MHz

CONVERSION POWER GAIN vs. TEMPERATURE

MAX2681

16

14

MAX2680/1/2-10

12

10

8

6

4

CONVERSION POWER GAIN (dB)

2

0

-40 0 20-20 40

fRF = 1950MHz

fRF = 2450MHz

TEMPERATURE (°C)

fRF = 900MHz

60

CONVERSION POWER GAIN vs. TEMPERATURE

17

15

MAX2680/1/2-11

13

11

9

7

5

CONVERSION POWER GAIN (dB)

3

10080

1

MAX2682

fRF = 900MHz

MAX2680/1/2-12

fRF = 1950MHz

fRF = 2450MHz

-40 0 20-20 40 60 80 100
TEMPERATURE (°C)

MAX2680/MAX2681/MAX2682

400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(Typical Operating Circuit, VCC= SHDN = +3.0V, P

RFIN

= -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
f

LO

= 1880MHz

f

IF

= 70MHz

P

RFIN

= -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
f

LO

= 1880MHz

f

IF

= 70MHz

P

RFIN

= -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
f

LO

= 1880MHz

f

IF

= 70MHz

P

RFIN

= -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

f

RF

900MHz
1950MHz
2450MHz

f

LO

970MHz
2020MHz
2210MHz

f

IF

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
P

LO

= -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

f

RF

900MHz
1950MHz
2450MHz

f

LO

970MHz
2020MHz
2210MHz

f

IF

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

f

RF

900MHz
1950MHz
2450MHz

f

LO

970MHz
2020MHz
2210MHz

f

IF

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
P

LO

= -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
P

LO

= -5dBm

MAX2680/MAX2681/MAX2682

400MHz to 2.5GHz, Low-Noise,

SiGe Downconverter Mixers

_______________________________________________________________________________________ 7

Typical Operating Characteristics (continued)

(Typical Operating Circuit, VCC= SHDN = +3.0V, P

RFIN

= -25dBm, PLO= -5dBm, TA= +25°C, unless otherwise noted.)

MAX2680

IF PORT IMPEDANCE vs. IF FREQUENCY

1200

1000

800

600

400

REAL IMPEDANCE (Ω)

200

0

0 200100 300 400 500

IF FREQUENCY (MHz)

fLO = 970MHz
P

LO

IMAGINARY

REAL

MAX2680/1/2-22

= -5dBm

0

-100

-200

-300

-400

-500

-600

1200

1000

REAL IMPEDANCE (Ω)

IMAGINARY IMPEDANCE (Ω)

MAX2680

LO PORT RETURN LOSS

+10

+5

0

-5

-10

-15

-20

RETURN LOSS (dB)

-25

-30

-35

-40
200 760 1320 1880 2440 3000

FREQUENCY (MHz)

MAX2680/1/2-25

IF PORT IMPEDANCE vs. IF FREQUENCY

MAX2681

fLO = 970MHz
P

LO

800

600

400

200

0

0 200100 300 400 500

IMAGINARY

REAL

IF FREQUENCY (MHz)

MAX2681

LO PORT RETURN LOSS

+10

+5

0

-5

-10

-15

-20

RETURN LOSS (dB)

-25

-30

-35

-40
200 760 1320 1880 2440 3000

FREQUENCY (MHz)

MAX2680/1/2-23

= -5dBm

0

-100

-200

-300

-400

-500

-600

IF PORT IMPEDANCE vs. IF FREQUENCY

800

700

600

500

400

300

REAL IMPEDANCE (Ω)

200

IMAGINARY IMPEDANCE (Ω)

100

0

0 200100 300 400 500

+10

+5

0

MAX2680/1/2-26

-5

-10

-15

-20

RETURN LOSS (dB)

-25

-30

-35

-40
200 760 1320 1880 2440 3000

MAX2682

MAX2680/1/2-24

fLO = 970MHz

= -5dBm

P

LO

IMAGINARY

REAL

IF FREQUENCY (MHz)

MAX2682

LO PORT RETURN LOSS

FREQUENCY (MHz)

0

-50

-100

-150

-200

-250

-300

IMAGINARY IMPEDANCE (Ω)

-350

-400

MAX2680/1/2-27

LO-to-IF AND LO-to-RF ISOLATION

MAX2680

35

30

25

20

LO-to-RF ISOLATION

15

ISOLATION (dB)

10

5

0

0 1000500 1500 2000 2500

LO FREQUENCY (MHz)

LO-to-IF ISOLATION

MAX2680/1/2-28

LO-to-IF AND LO-to-RF ISOLATION

MAX2681

40

35

30

25

20

15

ISOLATION (dB)

10

LO-to-RF ISOLATION

5

0

0 1000500 1500 2000 2500

LO FREQUENCY (MHz)

LO-to-IF ISOLATION

MAX2680/1/2-29

LO-to-IF AND LO-to-RF ISOLATION

MAX2682

35

30

25

20

ISOLATION (dB)

15

10

LO-to-RF ISOLATION

0 1000500 1500 2000 2500

LO-to-IF ISOLATION

LO FREQUENCY (MHz)

MAX2680/1/2-30

MAX2680/MAX2681/MAX2682

400MHz to 2.5GHz, Low-Noise,
SiGe Downconverter Mixers

8 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(Typical Operating Circuit, VCC= SHDN = +3.0V, P

RFIN

= -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 (50Ω source). AC­couple 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.

V

CC

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 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 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 VCCfor
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, 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 essen­tial for high-frequency RF circuit stability. Bypass V

CC

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.

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 V

CC

node. The VCCtraces branch out from this central
node, each going to a separate VCCnode 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 VCCpin.
At high frequencies, any signal leaking out of one sup­ply pin sees a relatively high impedance (formed by the
VCCtrace inductance) to the central VCCnode, 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 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.

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

1

SHDN

V

CC

RF

INPUT

LO

INPUT

C1

IFOUT

2

Z

2

Z

3

Z

1

3

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.

V

CC

+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

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

.)

6LSOT.EPS

PACKAGE OUTLINE, SOT-23, 6L

1

21-0058

F

1