dual, sige, high-linearity, 700mhz to 1000mhz ...general description the max19985a high-linearity,...

General DescriptionThe MAX19985A high-linearity, dual-channel, downcon-version mixer is designed to provide approximately8.7dB gain, +25.5dBm of IIP3, and 9.0dB of noise fig-ure for 700MHz to 1000MHz diversity receiver applica-tions. With an optimized LO frequency range of900MHz to 1300MHz, this mixer is ideal for high-sideLO injection architectures in the cellular and new700MHz bands. Low-side LO injection is supported bythe MAX19985, which is pin-pin and functionally com-patible with the MAX19985A.

In addition to offering excellent linearity and noise per-formance, the MAX19985A also yields a high levelof component integration. This device includes twodouble-balanced passive mixer cores, two LO buffers,a dual-input LO selectable switch, and a pair of differ-ential IF output amplifiers. On-chip baluns are also inte-grated to allow for single-ended RF and LO inputs.

The MAX19985A requires a nominal LO drive of 0dBmand a typical supply current of 330mA at VCC = +5.0Vor 280mA at VCC = +3.3V.

The MAX19985/MAX19985A are pin compatible withthe MAX19995/MAX19995A series of 1700MHz to2200MHz mixers and pin similar with the MAX19997A/MAX19999 series of 1850MHz to 3800MHz mixers,making this entire family of downconverters ideal forapplications where a common PCB layout is usedacross multiple frequency bands.

The MAX19985A is available in a 6mm x 6mm, 36-pinthin QFN package with an exposed pad. Electrical per-formance is guaranteed over the extended temperaturerange of TC = -40°C to +85°C.

Applications850MHz WCDMA and cdma2000® Base Stations

700MHz LTE/WiMAX™ Base Stations

GSM850/900 2G and 2.5G EDGE Base Stations

iDEN® Base Stations

Fixed Broadband Wireless Access

Wireless Local Loop

Private Mobile Radios

Military Systems

Features� 700MHz to 1000MHz RF Frequency Range

� 900MHz to 1300MHz LO Frequency Range

� 50MHz to 500MHz IF Frequency Range

� 8.7dB Typical Conversion Gain

� 9.0dB Typical Noise Figure

� +25.5dBm Typical Input IP3

� +12.6dBm Typical Input 1dB Compression Point

� 76dBc Typical 2LO-2RF Spurious Rejection atPRF = -10dBm

� Dual Channels Ideal for Diversity ReceiverApplications

� 48dB Typical Channel-to-Channel Isolation

� Low -3dBm to +3dBm LO Drive

� Integrated LO Buffer

� Internal RF and LO Baluns for Single-EndedInputs

� Built-In SPDT LO Switch with 46dB LO1-to-LO2Isolation and 50ns Switching Time

� Pin Compatible with the MAX19995/MAX19995ASeries of 1700MHz to 2200MHz Mixers

� Pin Similar to the MAX19997A/MAX19999 Seriesof 1850MHz to 3800MHz Mixers

� Single +5.0V or +3.3V Supply

� External Current-Setting Resistors Provide Optionfor Operating Device in Reduced-Power/Reduced-Performance Mode

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Dual, SiGe, High-Linearity, 700MHz to 1000MHzDownconversion Mixer with LO Buffer/Switch

________________________________________________________________ Maxim Integrated Products 1

19-4185; Rev 0; 8/08

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,or visit Maxim’s website at www.maxim-ic.com.

cdma2000 is a registered trademark of TelecommunicationsIndustry Association.

WiMAX is a trademark of WiMAX Forum.

iDEN is a registered trademark of Motorola, Inc.

Typical Application Circuit and Pin Configuration appear atend of data sheet.

+Denotes a lead-free/RoHS-compliant package.*EP = Exposed pad.T = Tape and reel.

Ordering InformationPART TEMP RANGE PIN-PACKAGE

MAX19985AETX+ -40°C to +85°C 36 Thin QFN-EP*

MAX19985AETX+T -40°C to +85°C 36 Thin QFN-EP*

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2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

+3.3V SUPPLY DC ELECTRICAL CHARACTERISTICS(Typical Application Circuit, VCC = 3.0V to 3.6V, TC = -40°C to +85°C. Typical values are at VCC = 3.3V, TC = +25°C, all parametersare guaranteed by design and not production tested, unless otherwise noted.)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.

Note 1: Based on junction temperature TJ = TC + (θJC x VCC x ICC). This formula can be used when the temperature of the exposedpad is known while the device is soldered down to a PCB. See the Applications Information section for details. The junctiontemperature must not exceed +150°C.

Note 2: Junction temperature TJ = TA + (θJA x VCC x ICC). This formula can be used when the ambient temperature of the PCB isknown. The junction temperature must not exceed +150°C.

Note 3: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.

Note 4: TC is the temperature on the exposed pad of the package. TA is the ambient temperature of the device and PCB.

VCC to GND...........................................................-0.3V to +5.5VLO1, LO2 to GND ...............................................................±0.3VAny Other Pins to GND...............................-0.3V to (VCC + 0.3V)RFMAIN, RFDIV, and LO_ Input Power ..........................+15dBmRFMAIN, RFDIV Current (RF is DC shorted

to GND through balun)....................................................50mAContinuous Power Dissipation (Note 1) ..............................8.8W

θJA (Notes 2, 3)..............................................................+38°C/WθJC (Note 3).....................................................................7.4°C/WOperating Temperature Range (Note 4) .....TC = -40°C to +85°CJunction Temperature ......................................................+150°CStorage Temperature Range .............................-65°C to +150°CLead Temperature (soldering, 10s) .................................+300°C

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage VCC R2 = R5 = 600Ω 3.0 3.3 3.6 V

Supply Current ICC Total supply current, VCC = 3.3V 280 mA

LOSEL Input High Voltage VIH 2 V

LOSEL Input Low Voltage VIL 0.8 V

+5.0V SUPPLY DC ELECTRICAL CHARACTERISTICS(Typical Application Circuit, VCC = 4.75V to 5.25V, TC = -40°C to +85°C. Typical values are at VCC = 5.0V, TC = +25°C, all parame-ters are production tested, unless otherwise noted.)


Supply Voltage VCC 4.75 5 5.25 V

Supply Current ICC 330 380 mA

LOSEL Input High Voltage VIH 2 V

LOSEL Input Low Voltage VIL 0.8 V

LOSEL Input Current IIH, IIL -10 +10 µA

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RECOMMENDED AC OPERATING CONDITIONS


RF Frequency fRF (Note 5) 700 1000 MHz

LO Frequency fLO (Note 5) 900 1300 MHz

U si ng M i ni - C i r cui ts TC 4- 1W- 17 4:1 tr ansfor m er as defined in the Typical Application Circuit,IF matching components affect the IFfrequency range (Note 5)

100 500

IF Frequency fIFUsing alternative Mini-Circuits TC4-1W-7A4:1 transformer, IF matching componentsaffect the IF frequency range (Note 5)

50 250

MHz

LO Drive Level PLO (Note 5) -3 +3 dBm

+5.0V SUPPLY AC ELECTRICAL CHARACTERISTICS(Typical Application Circuit, VCC = +4.75V to +5.25V, RF and LO ports are driven from 50Ω sources, PLO = -3dBm to +3dBm,PRF = -5dBm, fRF = 700MHz to 1000MHz, fLO = 900MHz to 1200MHz, fIF = 200MHz, fRF < fLO, TC = -40°C to +85°C. Typical valuesare at VCC = +5.0V, PRF = -5dBm, PLO = 0dBm, fRF =900MHz, fLO = 1100MHz, fIF = 200MHz, TC =+25°C, all parameters are guaran-teed by design and characterization, unless otherwise noted.) (Note 6)


fIF = 200MHz, fRF = 824MHz to 915MHz,TC = -40°C to +85°C

7.0 8.7 10.2

Conversion Power Gain GCfIF = 200MHz, fRF = 824MHz to 915MHz,TC = +25°C (Note 9)

7.7 8.7 9.7

dB

Conversion Power Gain Variationvs. Frequency

ΔGC

Flatness over any one of three frequencybands: fRF = 824MHz to 849MHz, fRF = 869MHz to 894MHz, fRF = 880MHz to 915MHz (Note 9)

0.15 0.3 dB

G ai n V ar i ati on Over Tem p er atur e TCG TC = -40°C to +85°C -0.012 dB/°C

TC = -40°C to +85°C 9.2 11.5

Noise Figure NF fRF = 850MHz, fIF = 200MHz,P LO = 0d Bm , TC = + 25°C , V C C = + 5.0V

9.0 10.3dB

Noise Figure TemperatureCoefficient

TCNF TC = -40°C to +85°C 0.018 dB/°C

Noise Figure Under BlockingCondition

NFB

+8dBm blocker tone applied to RF port,fRF = 900MHz, fLO = 1090MHz,PLO = -3dBm, fBLOCKER = 800MHz,VCC = +5.0V (Note 7)

18.8 22 dB

TC = -40°C to +85°C 10.0 12.6Input 1dB Compression Point IP1dB

TC = +25°C (Note 9) 11.0 12.6dBm

fRF = 824MHz to 915MHz,fRF1 - fRF2 = 1MHz, fIF = 200MHz,PRF = -5dBm/tone, TC = -40°C to +85°C

22.5 25.5

Third-Order Input Intercept Point IIP3fRF = 824MHz to 915MHz,fRF1 - fRF2 = 1MHz, fIF = 200MHz,PRF = -5dBm/tone, TC = +25°C (Note 9)

23.5 25.5

dBm

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PRF = -10dBm -63 -76

2LO-2RF Spur Rejection 2 x 2fRF = 800MHz,fLO = 1000MHz,fSPUR = 900MHz

PRF = -5dBm(Note 9)

-58 -71dBc

PRF = -10dBm -65 -78

3LO-3RF Spur Rejection 3 x 3fRF = 800MHz,fLO = 1000MHz,fSPUR = 933.3MHz

PRF = -5dBm(Note 9)

-60 -73dBc

LO Leakage at RF PortfLO = 900MHz to 1300MHz, PLO = +3dBm(Note 10)

-40 -20 dBm

fLO = 900MHz to 1200MHz, PLO = +3dBm(Note 10)

-38 -25

2LO Leakage at RF PortfL O = 1200M H z to 1300M H z, P L O = + 3d Bm (Note 10)

-35 -22

dBm

3LO Leakage at RF PortfLO = 900MHz to 1300MHz, PLO = +3dBm(Note 10)

-50 -28 dBm

4LO Leakage at RF PortfLO = 900MHz to 1300MHz, PLO = +3dBm(Note 9)

-25 -15 dBm

LO Leakage at IF PortfLO = 900MHz to 1300MHz, PLO = +3dBm(Note 10)

-35 -23 dBm

RF-to-IF Isolation fRF = 824MHz to 915MHz (Note 10) 30 38 dB

LO-to-LO IsolationPLO1 = +3dBm, PLO2 = +3dBm,fLO1 = 900MHz, fLO2 = 901MHz,PRF = -5dBm (Notes 8, 10)

40 46 dB

Channel-to-Channel IsolationRFM AIN ( RFD IV ) conver ted p ow er m easur ed at IFD IV ( IFM AIN ) , r el ati ve to IFM AIN ( IFD IV ) ,al l unused p or ts ter m i nated to 50Ω ( N ote 9)

40 48 dB

LO Switching Time 50% of LOS E L to IF settl ed w i thi n 2 d eg r ees 50 1000 ns

RF Input Impedance ZRF 50 Ω

RF Input Return LossLO on and IF terminated into matchedimpedance

20 dB

LO Input Impedance ZLO 50 Ω

RF and IF terminated into matchedimpedance, LO port selected

20

LO Input Return LossRF and IF terminated into matchedimpedance, LO port unselected

20

dB

IF Terminal Output Impedance ZIFNominal differential impedance at the IC’sIF output

200 Ω

IF Return LossRF terminated in 50Ω; transformed to 50Ω using external components shown in theTypical Application Circuit

18 dB

+5.0V SUPPLY AC ELECTRICAL CHARACTERISTICS (continued)(Typical Application Circuit, VCC = +4.75V to +5.25V, RF and LO ports are driven from 50Ω sources, PLO = -3dBm to +3dBm,PRF = -5dBm, fRF = 700MHz to 1000MHz, fLO = 900MHz to 1200MHz, fIF = 200MHz, fRF < fLO, TC = -40°C to +85°C. Typical valuesare at VCC = +5.0V, PRF = -5dBm, PLO = 0dBm, fRF =900MHz, fLO = 1100MHz, fIF = 200MHz, TC =+25°C, all parameters are guaran-teed by design and characterization, unless otherwise noted.) (Note 6)

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+3.3V SUPPLY AC ELECTRICAL CHARACTERISTICS(Typical Application Circuit, RF and LO ports are driven from 50Ω sources. Typical values are at VCC = +3.3V, PRF = -5dBm,PLO = 0dBm, fRF = 900MHz, fLO = 1100MHz, fIF = 200MHz, TC =+25°C, unless otherwise noted.) (Note 6)


Conversion Power Gain GC 8.7 dB

Conversion Power Gain Variationvs. Frequency

ΔGC

Flatness over any one of three frequencybands: fRF = 824MHz to 849MHz, fRF = 869MHz to 894MHz, fRF = 880MHz to 915MHz

0.15 dB

G ai n V ar i ati on Over Tem p er atur e TCG TC = -40°C to +85°C -0.012 dB/°C

Noise Figure NF 9.0 dB

Noise Figure TemperatureCoefficient

TCNF TC = -40°C to +85°C 0.018 dB/°C

Input 1dB Compression Point IP1dB 10.6 dBm

Third-Order Input Intercept Point IIP3fRF1 = 900MHz, fRF2 = 901MHz,fIF = 200MHz, PRF = -5dBm/tone

24.7 dBm

PRF = -10dBm -74.92LO-2RF Spur Rejection 2 x 2

fRF = 800MHz,fLO = 1000MHz,fSPUR = 900MHz PRF = -5dBm -69.9

dBc

PRF = -10dBm -783LO-3RF Spur Rejection 3 x 3

fRF = 800MHz,fLO = 1000MHz,fSPUR = 933.333MHz PRF = -5dBm -73

dBc

Maximum LO Leakage at RF Port fLO = 900MHz to 1300MHz, PLO = +3dBm -40 dBm

M axi m um 2LO Leakag e at RF P or t fLO = 900MHz to 1300MHz, PLO = +3dBm -42 dBm

Maximum LO Leakage at IF Port fLO = 900MHz to 1300MHz, PLO = +3dBm -34 dBm

Minimum RF-to-IF Isolation fRF = 824MHz to 915MHz 38 dB

LO-to-LO IsolationPLO1 = +3dBm, PLO2 = +3dBm,fLO1 = 900MHz, fLO2 = 901MHz (Note 8)

45 dB

Channel-to-Channel IsolationRFM AIN ( RFD IV ) conver ted p ow er m easur ed at IFD IV ( IFM AIN ) , r el ati ve to IFM AIN ( IFD IV ) ,al l unused p or ts ter m i nated to 50Ω

48 dB

LO Switching Time 50% of LOS E L to IF settl ed w i thi n 2 d eg r ees 50 ns

RF Input Impedance ZRF 50 Ω

RF Input Return LossLO on and IF terminated into matchedimpedance

21 dB

LO Input Impedance ZLO 50 Ω

RF and IF terminated into matchedimpedance, LO port selected

31

LO Input Return LossRF and IF terminated into matchedimpedance, LO port unselected

24

dB

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6 _______________________________________________________________________________________

Note 5: Not production tested. Operation outside this range is possible, but with degraded performance of some parameters. Seethe Typical Operating Characteristics. Performance is optimized for RF frequencies of 824MHz to 915MHz.

Note 6: All limits reflect losses of external components. Output measurements taken at IF outputs of Typical Application Circuit.Note 7: Measured with external LO source noise filtered so the noise floor is -174dBm/Hz. This specification reflects the effects of

all SNR degradations in the mixer including the LO noise, as defined in the Application Note 2021: Specifications andMeasurement of Local Oscillator Noise in Integrated Circuit Base Station Mixers.

Note 8: Measured at IF port at IF frequency. LOSEL may be in any logic state.Note 9: Limited production testing.Note 10: Guaranteed by production testing.

+3.3V SUPPLY AC ELECTRICAL CHARACTERISTICS (continued)(Typical Application Circuit, RF and LO ports are driven from 50Ω sources. Typical values are at VCC = +3.3V, PRF = -5dBm,PLO = 0dBm, fRF = 900MHz, fLO = 1100MHz, fIF = 200MHz, TC =+25°C, unless otherwise noted.) (Note 6)


IF Terminal Output Impedance ZIFNominal differential impedance at the IC’sIF output

200 Ω

IF Output Return LossRF terminated in 50Ω; transformed to 50Ωusing external components shown in theTypical Application Circuit

17 dB

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Typical Operating Characteristics(Typical Application Circuit, VCC = +5.0V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC =+25°C, unlessotherwise noted.)

CONVERSION GAIN vs. RF FREQUENCY

MAX

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5A to

c01

RF FREQUENCY (MHz)

CONV

ERSI

ON G

AIN

(dB)

900800

7

8

9

10

11

6700 1000

TC = +85°CTC = +25°C

TC = -30°C


MAX

1998

5A to

c02

RF FREQUENCY (MHz)

CONV

ERSI

ON G

AIN

(dB)

900800

7

8

9

10

11

6700 1000

PLO = -3dBm, 0dBm, +3dBm


MAX

1998

5A to

c03

RF FREQUENCY (MHz)

CONV

ERSI

ON G

AIN

(dB)

900800

7

8

9

10

11

6700 1000

VCC = 4.75V, 5.0V, 5.25V

INPUT IP3 vs. RF FREQUENCY

MAX

1998

5A to

c04

RF FREQUENCY (MHz)

INPU

T IP

3 (d

Bm)

900800

23

24

25

26

27

22700 1000

TC = +85°C

TC = +25°C

TC = -30°C

PRF = -5dBm/TONE

INPUT IP3 vs. RF FREQUENCYM

AX19

985A

toc0

5

RF FREQUENCY (MHz)

INPU

T IP

3 (d

Bm)

900800

23

24

25

26

27

22700 1000

PLO = +3dBm, 0dBm PLO = -3dBm

PRF = -5dBm/TONE


MAX

1998

5A to

c06

RF FREQUENCY (MHz)

INPU

T IP

3 (d

Bm)

900800

23

24

25

26

27

22700 1000

VCC = 5.0V

VCC = 5.25V

VCC = 4.75V

PRF = -5dBm/TONE

NOISE FIGURE vs. RF FREQUENCY

MAX

1998

5A to

c07

RF FREQUENCY (MHz)

NOIS

E FI

GURE

(dB)

900800

7

6

8

9

10

11

12

5700 1000

TC = +85°C

TC = +25°CTC = -30°C

NOISE FIGURE vs. RF FREQUENCY

MAX

1998

5A to

c08

RF FREQUENCY (MHz)

NOIS

E FI

GURE

(dB)

900800

7

6

8

9

10

11

12

5700 1000


NOISE FIGURE vs. RF FREQUENCYM

AX19

985A

toc0

9

RF FREQUENCY (MHz)

NOIS

E FI

GURE

(dB)

900800

7

6

8

9

10

11

12

5700 1000

VCC = 4.75V, 5.0V, 5.25V

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2LO-2RF RESPONSE vs. RF FREQUENCY

MAX

1998

5A to

c10

RF FREQUENCY (MHz)

2LO-

2RF

RESP

ONSE

(dBc

)

900800

55

60

65

70

75

80

50700 1000

TC = +85°CPRF = -5dBm

TC = +25°C

TC = -30°C


MAX

1998

5A to

c11

RF FREQUENCY (MHz)

2LO-

2RF

RESP

ONSE

(dBc

)

900800

55

60

65

70

75

80

50700 1000

PLO = 0dBm

PLO = +3dBm

PLO = -3dBm

PRF = -5dBm


MAX

1998

5A to

c12

RF FREQUENCY (MHz)

2LO-

2RF

RESP

ONSE

(dBc

)

900800

55

60

65

70

75

80

50700 1000

PRF = -5dBm

VCC = 4.75V, 5.0V, 5.25V


MAX

1998

5A to

c13

RF FREQUENCY (MHz)

3LO-

3RF

RESP

ONSE

(dBc

)

900800

65

75

85

95

55700 1000

PRF = -5dBm

TC = +85°CTC = +25°C

TC = -30°C

3LO-3RF RESPONSE vs. RF FREQUENCYM

AX19

985A

toc1

4

RF FREQUENCY (MHz)

3LO-

3RF

RESP

ONSE

(dBc

)

900800

65

75

85

95

55700 1000

PRF = -5dBm



MAX

1998

5A to

c15

RF FREQUENCY (MHz)

3LO-

3RF

RESP

ONSE

(dBc

)

900800

65

75

85

95

55700 1000

PRF = -5dBm

VCC = 4.75V, 5.0V, 5.25V

INPUT P1dB vs. RF FREQUENCY

MAX

1998

5A to

c16

RF FREQUENCY (MHz)

INPU

T P 1

dB (d

Bm)

900800

11

13

12

14

15

10700 1000

TC = +85°C

TC = +25°C

TC = -30°C


MAX

1998

5A to

c17

RF FREQUENCY (MHz)

INPU

T P 1

dB (d

Bm)

900800

11

13

12

14

15

10700 1000


INPUT P1dB vs. RF FREQUENCYM

AX19

985A

toc1

8

RF FREQUENCY (MHz)

INPU

T P 1

dB (d

Bm)

900800

11

13

12

14

15

10700 1000

VCC = 5.0V

VCC = 5.25V

VCC = 4.75V

Typical Operating Characteristics (continued)(Typical Application Circuit, VCC = +5.0V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC =+25°C, unlessotherwise noted.)

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CHANNEL ISOLATION vs. RF FREQUENCY

MAX

1998

5A to

c19

RF FREQUENCY (MHz)

CHAN

NEL

ISOL

ATIO

N (d

B)

900800

40

35

50

45

55

60

30700 1000

TC = -30°C, +25°C, +85°C


MAX

1998

5A to

c20

RF FREQUENCY (MHz)

CHAN

NEL

ISOL

ATIO

N (d

B)

900800

40

35

50

45

55

60

30700 1000



MAX

1998

5A to

c21

RF FREQUENCY (MHz)

CHAN

NEL

ISOL

ATIO

N (d

B)

900800

40

35

50

45

55

60

30700 1000

VCC = 4.75V, 5.0V, 5.25V

LO LEAKAGE AT IF PORTvs. LO FREQUENCY

MAX

1998

5A to

c22

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T IF

POR

T (d

Bm)

1100 11501000 1050950

-40

-45

-30

-35

-25

-20

-50900 1200

TC = -30°C

TC = +25°C, +85°C


MAX

1998

5A to

c23

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T IF

POR

T (d

Bm)

1150110010501000950

-45

-40

-35

-30

-25

-20

-50900 1200

PLO = +3dBm

PLO = 0dBm

PLO = -3dBm


MAX

1998

5A to

c24

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T IF

POR

T (d

Bm)

1150110010501000950

-45

-40

-35

-30

-25

-20

-50900 1200

VCC = 4.75V, 5.0V, 5.25V

RF-TO-IF ISOLATIONvs. RF FREQUENCY

MAX

1998

5A to

c25

RF FREQUENCY (MHz)

RF-T

O-IF

ISOL

ATIO

N (d

B)

800 900

45

40

35

50

30700 1000

TC = +85°C

TC = -30°C TC = +25°C


MAX

1998

5A to

c26

RF FREQUENCY (MHz)

RF-T

O-IF

ISOL

ATIO

N (d

B)

800 900

45

40

35

50

30700 1000



MAX

1998

5A to

c27

RF FREQUENCY (MHz)

RF-T

O-IF

ISOL

ATIO

N (d

B)

800 900

45

40

35

50

30700 1000

VCC = 4.75V, 5.0V, 5.25V


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LO LEAKAGE AT RF PORTvs. LO FREQUENCY

MAX

1998

5A to

c28

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T RF

POR

T (d

Bm)

800 900 11001000

-60

-50

-40

-30

-20

-70700 1200

TC = -30°C

TC = +85°C

TC = +25°C


MAX

1998

5A to

c29

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T RF

POR

T (d

Bm)

800 900 11001000

-60

-50

-40

-30

-20

-70700 1200



MAX

1998

5A to

c30

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T RF

POR

T (d

Bm)

800 900 11001000

-60

-50

-40

-30

-20

-70700 1200

VCC = 4.75V, 5.0V, 5.25V

2LO LEAKAGE AT RF PORTvs. LO FREQUENCY

MAX

1998

5A to

c31

LO FREQUENCY (MHz)

2LO

LEAK

AGE

AT R

F PO

RT (d

Bm)

800 900 11001000

-50

-40

-30

-20

-10

-60700 1200

TC = -30°C, +25°C, +85°C


MAX

1998

5A to

c32

LO FREQUENCY (MHz)

2LO

LEAK

AGE

AT R

F PO

RT (d

Bm)

800 900 11001000

-50

-40

-30

-20

-10

-60700 1200



MAX

1998

5A to

c33

LO FREQUENCY (MHz)

2LO

LEAK

AGE

AT R

F PO

RT (d

Bm)

800 900 11001000

-50

-40

-30

-20

-10

-60700 1200

VCC = 4.75V, 5.0V, 5.25V

LO SWITCH ISOLATIONvs. LO FREQUENCY

MAX

1998

5A to

c34

LO FREQUENCY (MHz)

LO S

WIT

CH IS

OLAT

ION

(dB)

1100 1300

45

40

35

50

30900 15001000 1200 1400

TC = +85°C

TC = -30°C

TC = +25°C


MAX

1998

5A to

c35

LO FREQUENCY (MHz)

LO S

WIT

CH IS

OLAT

ION

(dB)

1100 1300

45

40

35

50

30900 15001000 1200 1400

PLO = +3dBm

PLO = -3dBm, 0dBm


MAX

1998

5A to

c36

LO FREQUENCY (MHz)

LO S

WIT

CH IS

OLAT

ION

(dB)

1100 1300

45

40

35

50

30900 15001000 1200 1400

VCC = 4.75V, 5.0V, 5.25V


3LO-3RF RESPONSE vs. RF FREQUENCY(VARIOUS LO AND IF BIAS)

MAX

1998

5A to

c45

RF FREQUENCY (MHz)

3LO-

3RF

RESP

ONSE

(dBc

)

900800

60

65

55

75

50

70

80

85

45700 1000

SEE TABLE 1 FOR RESISTOR AND ICC VALUES

1, 2, 3, 4 PRF = -5dBm

5

7 6

2LO-2RF RESPONSE vs. RF FREQUENCY(VARIOUS LO AND IF BIAS)

MAX

1998

5A to

c44

RF FREQUENCY (MHz)

2LO-

2RF

RESP

ONSE

(dBc

)

900800

60

65

55

70

75

80

50700 1000


2, 3, 41 PRF = -5dBm

57

6

LO SELECTED RETURN LOSSvs. LO FREQUENCY

MAX

1998

5A to

c39

LO FREQUENCY (MHz)

LO S

ELEC

TED

RETU

RN L

OSS

(dB)

11001000850

40

30

20

10

0

50700 1300

PLO = +3dBmPLO = 0dBm

PLO = -3dBm

MA

X1

99

85

A


______________________________________________________________________________________ 11

RF PORT RETURN LOSSvs. RF FREQUENCY

MAX

1998

5A to

c37

RF FREQUENCY (MHz)

RF P

ORT

RETU

RN L

OSS

(dB)

900 950800750 850

25

20

15

10

5

0

30700 1000


IF = 200MHz

IF PORT RETURN LOSSvs. IF FREQUENCY

MAX

1998

5A to

c38

IF FREQUENCY (MHz)

IF P

ORT

RETU

RN L

OSS

(dB)

140 230 320 410

25

20

15

10

5

0

3050 500

LO = 900MHz

VCC = 4.75V, 5.0V, 5.25V

IF RETURN LOSS DEPENDS ONEXTERNAL IF COMPONENTS

LO UNSELECTED RETURN LOSSvs. LO FREQUENCY

MAX

1998

5A to

c40

LO FREQUENCY (MHz)

LO U

NSEL

ECTE

D RE

TURN

LOS

S (d

B)

11001000850

40

30

20

10

0

50700 1300


SUPPLY CURRENTvs. TEMPERATURE (TC)

MAX

1998

5A to

c41

TEMPERATURE (°C)

SUPP

LY C

URRE

NT (m

A)

-15 25 455 65

290

310

330

350

370

270-35 85

VCC = 5.25V

VCC = 4.75V

VCC = 5.0V

CONVERSION GAIN vs. RF FREQUENCY(VARIOUS LO AND IF BIAS)

MAX

1998

5A to

c42

RF FREQUENCY (MHz)

CONV

ERSI

ON G

AIN

(dB)

900800

7

8

9

10

11

6700 1000


1, 2, 3, 4

75

6

INPUT IP3 vs. RF FREQUENCY(VARIOUS LO AND IF BIAS)

MAX

1998

5A to

c43

RF FREQUENCY (MHz)

INPU

T IP

3 (d

Bm)

900800

20

22

16

18

24

26

28

14700 1000


2, 3, 41 1

45

7

6


MA

X1

99

85

A


12 ______________________________________________________________________________________

INPUT P1dB vs. RF FREQUENCY(VARIOUS LO AND IF BIAS)

MAX

1998

5A to

c46

RF FREQUENCY (MHz)

INPU

T P 1

dB (d

Bm)

900800

10

8

14

6

12

16

4700 1000


1, 2, 3, 4

57 6

CONVERSION GAIN vs. RF FREQUENCY(VARIOUS VALUES OF L3 AND L6)

MAX

1998

5A to

c47

RF FREQUENCY (MHz)

CONV

ERSI

ON G

AIN

(dB)

900

L = L3 = L6

800

8

7

10

9

11

6700 1000

L = 0Ω, 7.5nH, 15nH, 30nH

INPUT IP3 vs. RF FREQUENCY(VARIOUS VALUES OF L3 AND L6)

MAX

1998

5A to

c48

RF FREQUENCY (MHz)

INPU

T IP

3 (d

Bm)

900

L = L3 = L6

800

24

23

26

25

27

22700 1000

L = 0Ω, 7.5nH, 15nH

L = 30nH

2LO-2RF RESPONSE vs. RF FREQUENCY(VARIOUS VALUES OF L3 AND L6)

MAX

1998

5A to

c49

RF FREQUENCY (MHz)

2LO-

2RF

RESP

ONSE

(dBc

)

900

PRF = -5dBmL = L3 = L6

800

65

60

55

75

70

80

50700 1000

L = 30nH

L = 7.5nH L = 15nH

L = 0Ω

3LO-3RF RESPONSE vs. RF FREQUENCY(VARIOUS VALUES OF L3 AND L6)

MAX

1998

5A to

c50

RF FREQUENCY (MHz)

3LO-

3RF

RESP

ONSE

(dBc

)

900

PRF = -5dBmL = L3 = L6

800

75

65

85

95

55700 1000

L = 0Ω, 7.5nH, 15nH, 30nH

LO LEAKAGE AT IF PORT vs. LO FREQUENCY(VARIOUS VALUES OF L3 AND L6)

MAX

1998

5A to

c51

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T IF

POR

T (d

Bm)

11001000

-20

-30

-10

-50

-60

-40

0

-70900 12001050950 1150

L = 0Ω

L = 7.5nH

L = 30nH

L = 15nH

L = L3 = L6

RF-TO-IF ISOLATION vs. RF FREQUENCY(VARIOUS VALUES OF L3 AND L6)

MAX

1998

5A to

c52

RF FREQUENCY (MHz)

RF-T

O-IF

ISOL

ATIO

N (d

B)

900800

40

20

10

30

50

0700 1000

L = 0Ω

L = 7.5nH

L = 30nH L = 15nH L = L3 = L6


MA

X1

99

85

A


______________________________________________________________________________________ 13


CONVERSION GAINvs. RF FREQUENCY

MAX

1998

5A to

c53

RF FREQUENCY (MHz)

CONV

ERSI

ON G

AIN

(dB)

900800

10

8

7

9

11

6700 1000

TC = +85°C

TC = -30°C

TC = +25°C

VCC = 3.3V


MAX

1998

5A to

c54

RF FREQUENCY (MHz)

CONV

ERSI

ON G

AIN

(dB)

800 900

7

8

9

10

11

6700 1000


VCC = 3.3V


MAX

1998

5A to

c55

RF FREQUENCY (MHz)

CONV

ERSI

ON G

AIN

(dB)

800 900

7

8

9

10

11

6700 1000

VCC = 3.0V, 3.3V, 3.6V


MAX

1998

5A to

c56

RF FREQUENCY (MHz)

INPU

T IP

3 (d

Bm)

900800

25

23

22

24

26

21700 1000

TC = +85°C

TC = -30°C

TC = +25°C

VCC = 3.3VPRF = -5dBm/TONE

INPUT IP3 vs. RF FREQUENCYM

AX19

985A

toc5

7

RF FREQUENCY (MHz)

INPU

T IP

3 (d

Bm)

900800

25

23

22

24

26

21700 1000

PLO = +3dBm

PLO = -3dBm

PLO = 0dBm

VCC = 3.3VPRF = -5dBm/TONE


MAX

1998

5A to

c58

RF FREQUENCY (MHz)

INPU

T IP

3 (d

Bm)

900800

25

23

22

24

26

21700 1000

VCC = 3.6V

VCC = 3.0V

VCC = 3.3V

PRF = -5dBm/TONE

NOISE FIGUREvs. RF FREQUENCY

MAX

1998

5A to

c59

RF FREQUENCY (MHz)

NOIS

E FI

GURE

(dB)

900800

11

8

7

10

6

9

12

5700 1000

TC = +85°C

TC = -30°CTC = +25°C

VCC = 3.3V


MAX

1998

5A to

c60

RF FREQUENCY (MHz)

NOIS

E FI

GURE

(dB)

900800

11

8

7

10

6

9

12

5700 1000


VCC = 3.3V


MAX

1998

5A to

c61

RF FREQUENCY (MHz)

NOIS

E FI

GURE

(dB)

900800

11

8

7

10

6

9

12

5700 1000

VCC = 3.0V, 3.3V, 3.6V

MA

X1

99

85

A


14 ______________________________________________________________________________________

2LO-2RF RESPONSEvs. RF FREQUENCY

MAX

1998

5A to

c62

RF FREQUENCY (MHz)

2LO-

2RF

RESP

ONSE

(dBc

)

900800

75

60

55

70

65

80

50700 1000

TC = +85°C

PRF = -5dBm

TC = -30°CTC = +25°C

VCC = 3.3V


MAX

1998

5A to

c63

RF FREQUENCY (MHz)

2LO-

2RF

RESP

ONSE

(dBc

)

900800

75

60

55

70

65

80

50700 1000

PRF = -5dBm

PLO = +3dBm

PLO = -3dBm

PLO = 0dBm

VCC = 3.3V


MAX

1998

5A to

c64

RF FREQUENCY (MHz)

2LO-

2RF

RESP

ONSE

(dBc

)

900800

75

60

55

70

65

80

50700 1000

PRF = -5dBm

VCC = 3.0V, 3.3V, 3.6V


MAX

1998

5A to

c65

RF FREQUENCY (MHz)

3LO-

3RF

RESP

ONSE

(dBc

)

900800

65

85

75

95

55700 1000

TC = +85°C

PRF = -5dBm

TC = -30°C

TC = +25°C

VCC = 3.3V


MAX

1998

5A to

c66

RF FREQUENCY (MHz)

3LO-

3RF

RESP

ONSE

(dBc

)

900800

65

85

75

95

55700 1000

PRF = -5dBm


VCC = 3.3V


MAX

1998

5A to

c67

RF FREQUENCY (MHz)

3LO-

3RF

RESP

ONSE

(dBc

)

900800

65

85

75

95

55700 1000

PRF = -5dBm

VCC = 3.6V

VCC = 3.0V

VCC = 3.3V


MAX

1998

5A to

c68

RF FREQUENCY (MHz)

INPU

T P 1

dB (d

Bm)

900800

9

12

8

11

10

13

7700 1000

TC = +85°C

TC = -30°C

TC = +25°C

VCC = 3.3V


MAX

1998

5A to

c69

RF FREQUENCY (MHz)

INPU

T P 1

dB (d

Bm)

900800

9

12

8

11

10

13

7700 1000


VCC = 3.3V

INPUT P1dB vs. RF FREQUENCYM

AX19

985A

toc7

0

RF FREQUENCY (MHz)

INPU

T P 1

dB (d

Bm)

900800

9

12

8

11

10

13

7700 1000

VCC = 3.6V

VCC = 3.0V

VCC = 3.3V


MA

X1

99

85

A


______________________________________________________________________________________ 15

CHANNEL ISOLATIONvs. RF FREQUENCY

MAX

1998

5A to

c71

RF FREQUENCY (MHz)

CHAN

NEL

ISOL

ATIO

N (d

B)

900800

40

55

35

50

45

60

30700 1000

TC = -30°C, +25°C, +85°C

VCC = 3.3V


MAX

1998

5A to

c72

RF FREQUENCY (MHz)

CHAN

NEL

ISOL

ATIO

N (d

B)

900800

40

55

35

50

45

60

30700 1000


VCC = 3.3V


MAX

1998

5A to

c73

RF FREQUENCY (MHz)

CHAN

NEL

ISOL

ATIO

N (d

B)

900800

40

55

35

50

45

60

30700 1000

VCC = 3.0V, 3.3V, 3.6V


MAX

1998

5A to

c74

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T IF

POR

T (d

Bm)

11001000

-40

-25

-45

-30

-35

-20

-50900 12001050950 1150

TC = +85°C

TC = -30°C

TC = +25°C

VCC = 3.3V


MAX

1998

5A to

c75

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T IF

POR

T (d

Bm)

11001000

-40

-25

-45

-30

-35

-20

-50900 12001050950 1150

PLO = +3dBm

PLO = -3dBm

PLO = 0dBm

VCC = 3.3V


MAX

1998

5A to

c76

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T IF

POR

T (d

Bm)

11001000

-40

-25

-45

-30

-35

-20

-50900 12001050950 1150

VCC = 3.6V

VCC = 3.0V

VCC = 3.3V


MAX

1998

5A to

c77

RF FREQUENCY (MHz)

RF-T

O-IF

ISOL

ATIO

N (d

B)

900800

45

35

40

50

30700 1000

TC = +85°C

TC = -30°CTC = +25°C

VCC = 3.3V


MAX

1998

5A to

c78

RF FREQUENCY (MHz)

RF-T

O-IF

ISOL

ATIO

N (d

B)

900800

45

35

40

50

30700 1000


VCC = 3.3V


MAX

1998

5A to

c79

RF FREQUENCY (MHz)

RF-T

O-IF

ISOL

ATIO

N (d

B)

900800

45

35

40

50

30700 1000

VCC = 3.0V, 3.3V, 3.6V


MA

X1

99

85

A


16 ______________________________________________________________________________________


MAX

1998

5A to

c80

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T RF

POR

T (d

Bm)

800 1000900 1100

-30

-50

-40

-20

-60700 1200

TC = +85°C

TC = -30°C TC = +25°C

VCC = 3.3V


MAX

1998

5A to

c81

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T RF

POR

T (d

Bm)

800 1000900 1100

-30

-50

-40

-20

-60700 1200


VCC = 3.3V


MAX

1998

5A to

c82

LO FREQUENCY (MHz)

LO L

EAKA

GE A

T RF

POR

T (d

Bm)

800 1000900 1100

-30

-50

-40

-20

-60700 1200

VCC = 3.6V

VCC = 3.0V

VCC = 3.3V


MAX

1998

5A to

c83

LO FREQUENCY (MHz)

2LO

LEAK

AGE

AT R

F PO

RT (d

Bm)

800 1000900 1100

-30

-20

-50

-40

-10

-60700 1200

TC = -30°C, +25°C, +85°C

VCC = 3.3V


MAX

1998

5A to

c84

LO FREQUENCY (MHz)

2LO

LEAK

AGE

AT R

F PO

RT (d

Bm)

800 1000900 1100

-30

-20

-50

-40

-10

-60700 1200


VCC = 3.3V


MAX

1998

5A to

c85

LO FREQUENCY (MHz)

2LO

LEAK

AGE

AT R

F PO

RT (d

Bm)

800 1000900 1100

-30

-20

-50

-40

-10

-60700 1200

VCC = 3.6V

VCC = 3.0V

VCC = 3.3V

LO SWITCH ISOLATIONvs. RF FREQUENCY

MAX

1998

5A to

c86

LO FREQUENCY (MHz)

LO S

WIT

CH IS

OLAT

ION

(dB)

13001000 1200 14001100

45

35

40

50

30900 1500

TC = -30°C

TC = +25°CTC = +85°C

VCC = 3.3V

LO SWITCH ISOLATIONvs. RF FREQUENCY

MAX

1998

5A to

c87

LO FREQUENCY (MHz)

LO S

WIT

CH IS

OLAT

ION

(dB)

13001000 1200 14001100

45

35

40

50

30900 1500

PLO = -3dBm, 0dBm

PLO = +3dBm

VCC = 3.3V


MAX

1998

5A to

c88

LO FREQUENCY (MHz)

LO S

WIT

CH IS

OLAT

ION

(dB)

13001000 1200 14001100

45

35

40

50

30900 1500

VCC = 3.0V, 3.3V, 3.6V


Table 1. DC Current vs. Bias ResistorSettings

MA

X1

99

85

A


______________________________________________________________________________________ 17

RF PORT RETURN LOSSvs. RF FREQUENCY

MAX

1998

5A to

c89

RF FREQUENCY (MHz)

RF P

ORT

RETU

RN L

OSS

(dB)

900750 850 950800

5

20

10

25

15

0

30700 1000


IF = 200MHzVCC = 3.3V

IF PORT RETURN LOSSvs. IF FREQUENCY

MAX

1998

5A to

c90

IF FREQUENCY (MHz)

IF P

ORT

RETU

RN L

OSS

(dB)

140 230 410

5

20

10

25

15

0

3050 500320

LO = 900MHz

VCC = 3.0V, 3.3V, 3.6V

IF RETURN LOSS DEPENDS ONEXTERNAL COMPONENTS

LO SELECTED RETURN LOSSvs. LO FREQUENCY

MAX

1998

5A to

c91

LO FREQUENCY (MHz)

LO S

ELEC

TED

RETU

RN L

OSS

(dB)

1150

30

40

10

20

0

50700 13001000850

PLO = +3dBm

PLO = -3dBm

PLO = 0dBm

VCC = 3.3V

LO UNSELECTED RETURN LOSSvs. LO FREQUENCY

MAX

1998

5A to

c92

LO FREQUENCY (MHz)

LO U

NSEL

ECTE

D RE

TURN

LOS

S (d

B)

1150

30

40

10

20

0

50700 13001000850


VCC = 3.3V

SUPPLY CURRENTvs. TEMPERATURE (TC)

MAX

1998

5A to

c93

TEMPERATURE (°C)

SUPP

LY C

URRE

NT (m

A)

455

320

280

260

240

220

300

340

200-35 8525-15 65

VCC = 3.6V

VCC = 3.0V

VCC = 3.3V


BIASCONDITION

D C CU R R EN T ( m A )

R1 AND R4VALUES (Ω)

R2 AND R5VALUES (Ω)

1 359.4 698 800

2 331.8 698 1100

3 322.8 698 1200

4 311.7 698 1400

5 268.2 1100 1200

6 244.4 1400 1200

7 223.7 1820 1200

Note: See TOCs 42–46 for performance trade-offs vs. DC biascondition.

MA

X1

99

85

A


18 ______________________________________________________________________________________

Pin DescriptionPIN NAME FUNCTION

1 RFMAINMain Channel RF input. Internally matched to 50Ω. Requires an input DC-blockingcapacitor.

2 TAPMAINMain Channel Balun Center Tap. Bypass to GND with 39pF and 0.033µF capacitors asclose as possible to the pin with the smaller value capacitor closer to the part.

3, 5, 7, 12, 20, 22,24, 25, 26, 34

GND Ground

4, 6, 10, 16, 21,30, 36

VCCPower Supply. Bypass to GND with 0.01µF capacitors as close as possible to the pin. Pins4 and 6 do not require bypass capacitors.

8 TAPDIVDiversity Channel Balun Center Tap. Bypass to GND with 39pF and 0.033µF capacitors asclose as possible to the pin with the smaller value capacitor closer to the part.

9 RFDIVDiversity Channel RF Input. Internally matched to 50Ω. Requires an input DC-blockingcapacitor.

11 IFDBIASIF Diversity Amplifier Bias Control. Connect a resistor from this pin to ground to set the biascurrent for the diversity IF amplifier (see the Typical Operating Characteristics for typicalperformance vs. resistor value).

13, 14 IFD+, IFD-Diversity Mixer Differential IF Outputs. Connect pullup inductors from each of these pins toVCC (see the Typical Application Circuit).

15 LEXTDDiversity External Inductor Connection. Connect a parallel combination of an inductor anda 500Ω resistor from this pin to ground to increase the RF-to-IF and LO-to-IF isolation (seethe Typical Operating Characteristics for typical performance vs. inductor value).

17 LODBIASLO Diversity Amplifier Bias Control. Connect a resistor from this pin to ground to set thebias current for the diversity LO amplifier (see the Typical Operating Characteristics fortypical performance vs. resistor value).

18, 28 N.C. No Connection. Not internally connected.

19 LO1Local Oscillator 1 Input. This input is internally matched to 50Ω. Requires an input DC-blocking capacitor.

23 LOSEL Local Oscillator Select. Set this pin to high to select LO1. Set to low to select LO2.

27 LO2Local Oscillator 2 Input. This input is internally matched to 50Ω. Requires an input DC-blocking capacitor.

29 LOMBIASLO Main Amplifier Bias Control. Connect a resistor from this pin to ground to set the biascurrent for the main LO amplifier (see the Typical Operating Characteristics for typicalperformance vs. resistor value).

31 LEXTMMain External Inductor Connection. Connect a parallel combination of an inductor and a500Ω resistor from this pin to ground to increase the RF-to-IF and LO-to-IF isolation (seeTypical Operating Characteristics for typical performance vs. inductor value).

32, 33 IFM-, IFM+Main Mixer Differential IF Outputs. Connect pullup inductors from each of these pins to VCC(see the Typical Application Circuit).

35 IFMBIASIF Main Amplifier Bias Control. Connect a resistor from this pin to ground to set the biascurrent for the main IF amplifier (see the Typical Operating Characteristics for typicalperformance vs. resistor value).

— EPExposed Pad. Internally connected to GND. Connect to a large ground plane usingmultiple vias to maximize thermal and RF performance.

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Detailed DescriptionThe MAX19985A is a dual-channel downconverterdesigned to provide 8.7dB of conversion gain,+25.5dBm of IIP3, +12.6dBm typical input 1dB com-pression point, and a 9.0dB noise figure.

In addition to its high-linearity performance, theMAX19985A achieves a high level of component inte-gration. The device integrates two double-balancedmixers for two-channel downconversion. Both the mainand diversity channels include a balun and matchingcircuitry to allow 50Ω single-ended interfaces to the RFports and the two LO ports. An integrated single-pole/double-throw (SPDT) switch provides 50ns switchingtime between the two LO inputs with 46dB of LO-to-LOisolation and -40dBm of LO leakage at the RF port.Furthermore, the integrated LO buffers provide a highdrive level to each mixer core, reducing the LO driverequired at the MAX19985A’s inputs to a range of-3dBm to +3dBm. The IF ports for both channels incor-porate differential outputs for downconversion, which isideal for providing enhanced 2LO-2RF performance.

Specifications are guaranteed over broad frequencyranges to allow for use in WCDMA, GSM/EDGE, iDEN,cdma2000, and LTE/WiMAX cellular and 700MHz bandbase stations. The MAX19985A is specified to operateover an RF input range of 700MHz to 1000MHz, an LOrange of 900MHz to 1300MHz, and an IF range of50MHz to 500MHz. The external IF components set thelower frequency range (see the Typical OperatingCharacteristics for details). Operation beyond theseranges is possible (see the Typical OperatingCharacteristics for additional information). Although thisdevice is optimized for high-side LO injection applica-tions, it can operate in low-side LO injection modes aswell. However, performance degrades as fLO continuesto decrease. For increased low-side LO performance,refer to the MAX19985 data sheet.

RF Port and BalunThe RF input ports of both the main and diversity chan-nels are internally matched to 50Ω, requiring no exter-nal matching components. A DC-blocking capacitor isrequired as the input is internally DC shorted to groundthrough the on-chip balun. The RF port input return lossis typically 20dB over the RF frequency range of770MHz to 915MHz.

LO Inputs, Buffer, and BalunThe MAX19985A is optimized for a 900MHz to1300MHz LO frequency range. As an added feature,the MAX19985A includes an internal LO SPDT switchfor use in frequency-hopping applications. The switchselects one of the two single-ended LO ports, allowingthe external oscillator to settle on a particular frequencybefore it is switched in. LO switching time is typically50ns, which is more than adequate for typical GSMapplications. If frequency hopping is not employed,simply set the switch to either of the LO inputs. Theswitch is controlled by a digital input (LOSEL), wherelogic-high selects LO1 and logic-low selects LO2. LO1and LO2 inputs are internally matched to 50Ω, requiringonly an 82pF DC-blocking capacitor. To avoid damageto the part, voltage MUST be applied to VCC beforedigital logic is applied to LOSEL. Alternatively, a 1kΩresistor can be placed in series at the LOSEL to limitthe input current in applications where LOSEL isapplied before VCC.

The main and diversity channels incorporate a two-stage LO buffer that allows for a wide-input powerrange for the LO drive. The on-chip low-loss baluns,along with LO buffers, drive the double-balanced mix-ers. All interfacing and matching components from theLO inputs to the IF outputs are integrated on-chip.

High-Linearity MixerThe core of the MAX19985A dual-channel downcon-verter consists of two double-balanced, high-performance passive mixers. Exceptional linearity isprovided by the large LO swing from the on-chip LObuffers. When combined with the integrated IF ampli-fiers, the cascaded IIP3, 2LO-2RF rejection, and noisefigure performance are typically +25.5dBm, 76dBc,and 9.0dB, respectively.

Differential IFThe MAX19985A has an IF frequency range of 50MHzto 500MHz, where the low-end frequency depends onthe frequency response of the external IF components.Note that these differential ports are ideal for providingenhanced IIP2 performance. Single-ended IF applica-tions require a 4:1 (impedance ratio) balun to transformthe 200Ω differential IF impedance to a 50Ω single-ended system. After the balun, the return loss istypically 18dB. The user can use a differential IF ampli-fier on the mixer IF ports, but a DC block is required onboth IFD+/IFD- and IFM+/IFM- ports to keep externalDC from entering the IF ports of the mixer.

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Applications InformationInput and Output Matching

The RF and LO inputs are internally matched to 50Ω. Nomatching components are required. The RF port inputreturn loss is typically 20dB over the RF frequency rangeof 770MHz to 915MHz and return loss at the LO ports aretypically 20dB over the entire LO range. RF and LO inputsrequire only DC-blocking capacitors for interfacing.

The IF output impedance is 200Ω (differential). Forevaluation, an external low-loss 4:1 (impedance ratio)balun transforms this impedance to a 50Ω single-endedoutput (see the Typical Application Circuit).

Externally Adjustable BiasEach channel of the MAX19985A has two pins (LO_BIAS,IF_BIAS) that allow external resistors to set the internalbias currents. Nominal values for these resistors are givenin Table 2. Larger-value resistors can be used to reducepower dissipation at the expense of some performanceloss. See the Typical Operating Characteristics to evaluatethe power vs. performance tradeoff. If ±1% resistors arenot readily available, ±5% resistors can be substituted.

LEXT_ InductorsFor applications requiring optimum RF-to-IF and LO-to-IF isolation, connect a parallel combination of a low-ESR inductor and a 500Ω resistor from LEXT_ (pins 15and 31) to ground. When improved isolation is notrequired, connect LEXT_ to ground using a 0Ω resis-tance. See the Typical Operating Characteristics toevaluate the isolation vs. inductor value tradeoff.

Layout ConsiderationsA properly designed PCB is an essential part of anyRF/microwave circuit. Keep RF signal lines as short aspossible to reduce losses, radiation, and inductance.The load impedance presented to the mixer must be sothat any capacitance from both IF- and IF+ to grounddoes not exceed several picofarads. For the best perfor-mance, route the ground pin traces directly to theexposed pad under the package. The PCB exposedpad MUST be connected to the ground plane of thePCB. It is suggested that multiple vias be used to con-nect this pad to the lower-level ground planes. Thismethod provides a good RF/thermal-conduction path forthe device. Solder the exposed pad on the bottom of the

Table 2. Component ValuesCOMPONENT VALUE DESCRIPTION

C1, C2, C7, C8 39pF Microwave capacitors (0402)

C3, C6 0.033µF Microwave capacitors (0603)

C4, C5 — Not used

C9, C13, C15, C17, C18 0.01µF Microwave capacitors (0402)

C10, C11, C12, C19, C20, C21 150pF Microwave capacitors (0603)

C14, C16 82pF Microwave capacitors (0402)

L1, L2, L4, L5 330nH Wire-wound high-Q inductors (0805)

L3, L6 30nHWire-wound high-Q inductors (0603). Smaller values can be used at the expense ofsome performance loss (see the Typical Operating Characteristics).

R1, R4 698Ω ±1% resistors (0402). Larger values can be used to reduce power at the expense ofsome performance loss (see the Typical Operating Characteristics).

1.2kΩ±1% resistors (0402). Use for VCC = +5.0V applications. Larger values can be usedto reduce power at the expense of some performance loss (see the TypicalOperating Characteristics).R2, R5

600Ω ±1% resistors (0402). Use for VCC = +3.3V applications.

R3, R6 0Ω ±1% resistors (1206)

R7, R8 500Ω ±1% resistors (0402)

T1, T2 4:1Transformers (200:50)Mini-Circuits TC4-1W-7A

U1 — MAX19985A IC

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device package to the PCB. The MAX19985A evaluationkit can be used as a reference for board layout. Gerberfiles are available upon request at www.maxim-ic.com.

Power-Supply BypassingProper voltage-supply bypassing is essential for high-frequency circuit stability. Bypass each VCC pin andTAPMAIN/TAPDIV with the capacitors shown in theTypical Application Circuit (see Table 2 for componentvalues). Place the TAPMAIN/TAPDIV bypass capacitorsto ground within 100 mils of the pin.

Exposed Pad RF/Thermal ConsiderationsThe exposed pad (EP) of the MAX19985A’s 36-pin thinQFN-EP package provides a low thermal-resistancepath to the die. It is important that the PCB on which theMAX19985A is mounted be designed to conduct heatfrom the EP. In addition, provide the EP with a low-inductance path to electrical ground. The EP MUST besoldered to a ground plane on the PCB, either directlyor through an array of plated via holes.

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Typical Application Circuit

MAX19985A

5

6

4

3

23

22

24

IFDB

IAS

IFD+ IFD-

LEXT

D

V CC

25

V CC

IFM

BIAS

IFM

+

IFM

-

V CC

LEXT

M

LOM

BIAS

10 11

VCC

13 14 15 16

3536 34 32 31 30

GND

VCC

GND

GND

LOSEL

GND

GND

GND

12

33

7 21GND

GNDC15

9 19RFDIV LO1

VCC

8 20TAPDIV

GND

2 26GND

R1

TAPMAIN

1 27LO2

LO1

LO2

+

N.C.

N.C.

18

28V C

C

LODB

IAS

17

29

RFMAIN

L3

L2

L1

EXPOSEDPAD

C16

C20

C19

C21

LOSELECT

IF MAINOUTPUT

IF DIVOUTPUT

C14

VCC

RF DIVINPUT

RF MAININPUT

C1

C8

C3 C2

C4

VCC

C5

VCC

C6 C7

C18

VCC

VCC

C17

VCC

R2

T1

4:1

R3

R4

L5

L4C10

C11

C12

C9

VCC

VCC

C13

VCC

R5

T2

4:1

R6

L6 R8

R7

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Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses areimplied. 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 ____________________ 23

© 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.

Pin Configuration/Functional Diagram

MAX19985A

THIN QFN-EP6mm x 6mm

TOP VIEW (WITHEXPOSED PAD ON

THE BOTTOM OF THEPACKAGE)

5

6

4

3

23

22

24

IFDB

IAS

IFD+ IFD-

LEXT

D

V CC

25

V CC

IFM

BIAS

IFM

+

IFM

-

V CC

LEXT

M

LOM

BIAS

10 11

VCC

13 14 15 16

3536 34 32 31 30

GND

VCC

GND

GND

LOSEL

GND

GND

GND

12

33

7 21GND

GND

9 19RFDIV LO1

+

VCC

8 20TAPDIV

GND

2 26 GNDTAPMAIN

1 27 LO2

N.C.

N.C.

18

28

V CC

LODB

IAS

17

29

RFMAIN

EXPOSEDPAD

Chip InformationPROCESS: SiGe BiCMOS

Package InformationFor the latest package outline information and land patterns, goto www.maxim-ic.com/packages.

PACKAGE TYPE PACKAGE CODE DOCUMENT NO.

36 Thin QFN-EP T3666+2 21-0141

http://pdfserv.maxim-ic.com/package_dwgs/21-0141.PDF

dual, sige, high-linearity, 700mhz to 1000mhz ...general description the max19985a high-linearity,...

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