MAXIM MAX2021 Technical data

General Description

The MAX2021 low-noise, high-linearity, direct upcon­version/downconversion quadrature modulator/demod­ulator is designed for RFID handheld and portal
readers, as well as single and multicarrier 750MHz to
1200MHz GSM/EDGE, cdma2000®, WCDMA, and
iDEN®base-station applications. Direct conversion
architectures are advantageous since they significantly
reduce transmitter or receiver cost, part count, and
power consumption as compared to traditional IF-based
double conversion systems.

In addition to offering excellent linearity and noise perfor­mance, the MAX2021 also yields a high level of compo­nent integration. This device includes two matched
passive mixers for modulating or demodulating in-phase
and quadrature signals, two LO mixer amplifier drivers,
and an LO quadrature splitter. On-chip baluns are also
integrated to allow for single-ended RF and LO connec­tions. As an added feature, the baseband inputs have
been matched to allow for direct interfacing to the trans­mit DAC, thereby eliminating the need for costly I/Q
buffer amplifiers.

The MAX2021 operates from a single +5V supply. It is
available in a compact 36-pin thin QFN package (6mm
x 6mm) with an exposed paddle. Electrical perfor­mance is guaranteed over the extended -40°C to
+85°C temperature range.

Applications

RFID Handheld and Portal Readers

Single and Multicarrier WCDMA 850 Base Stations

Single and Multicarrier cdmaOne™ and cdma2000
Base Stations

GSM 850/GSM 900 EDGE Base Stations

Predistortion Transmitters and Receivers

WiMAX Transmitters and Receivers

Fixed Broadband Wireless Access

Military Systems

Microwave Links

Digital and Spread-Spectrum Communication
Systems

Video-on-Demand (VOD) and DOCSIS Compliant
Edge QAM Modulation

Cable Modem Termination Systems (CMTS)

Features

♦ 750MHz to 1200MHz RF Frequency Range

♦ Scalable Power: External Current-Setting

Resistors Provide Option for Operating Device in
Reduced-Power/Reduced-Performance Mode

♦ 36-Pin, 6mm x 6mm TQFN Provides High Isolation

in a Small Package

Modulator Operation:

♦ Meets 4-Carrier WCDMA 65dBc ACLR

♦ +21dBm Typical OIP3

♦ +58dBm Typical OIP2

♦ +16.7dBm Typical OP

1dB

♦ -32dBm Typical LO Leakage

♦ 43.5dBc Typical Sideband Suppression

♦ -174dBm/Hz Output Noise Density

♦ DC to 300MHz Baseband Input Allows a Direct

Launch DAC Interface, Eliminating the Need for
Costly I/Q Buffer Amplifiers

♦ DC-Coupled Input Allows Ability for Customer

Offset Voltage Control

Demodulator Operation:

♦ +35.2dBm Typical IIP3

♦ +76dBm Typical IIP2

♦ > 30dBm IP

1dB

♦ 9.2dB Typical Conversion Loss

♦ 9.3dB Typical NF

♦ 0.06dB Typical I/Q Gain Imbalance

♦ 0.15° I/Q Typical Phase Imbalance

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion

750MHz to 1200MHz Quadrature Mod/Demod

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-3918; Rev 0; 3/06

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

EVALUATION KIT AVAILABLE

PART

TEMP RANGE

PIN-PACKAGE

PKG

CODE

MAX2021ETX

T3666-2

MAX2021ETX-T

T3666-2

MAX2021ETX+

T3666-2

MAX2021ETX+T

T3666-2

*EP = Exposed paddle. + = Lead free.

-T = Tape-and-reel package.

cdma2000 is a registered trademark of Telecommunications
Industry Association.
iDEN is a registered trademark of Motorola, Inc.
cdmaOne is a trademark of CDMA Development Group.

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

36 Thin QFN-EP*

(6mm x 6mm)

36 Thin QFN-EP*

(6mm x 6mm)

36 Thin QFN-EP*

(6mm x 6mm)

36 Thin QFN-EP*

(6mm x 6mm)

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod

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.

VCC_ to GND ........................................................-0.3V to +5.5V

BBI+, BBI-, BBQ+, BBQ- to GND...............-3.5V to (V

CC

+ 0.3V)

LO, RF to GND Maximum Current ......................................30mA

RF Input Power ...............................................................+30dBm

Baseband Differential I/Q Input Power (Note A) ............+20dBm

LO Input Power...............................................................+10dBm

RBIASLO1 Maximum Current .............................................10mA

RBIASLO2 Maximum Current .............................................10mA

RBIASLO3 Maximum Current .............................................10mA

θJA(without air flow) ..........................................…………34°C/W

θ

JA

(2.5m/s air flow) .........................................................28°C/W

θ

JC

(junction to exposed paddle) ...................................8.5°C/W

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering 10s, non-lead free)...........+245°C

Lead Temperature (soldering 10s, lead free) ..................+260°C

DC ELECTRICAL CHARACTERISTICS

(MAX2021 Typical Application Circuit, VCC= +4.75V to +5.25V, GND = 0V, I/Q inputs terminated into 100Ω differential, LO input terminat­ed into 50Ω, RF output terminated into 50Ω, 0V common-mode input, R1 = 432Ω, R2 = 619Ω, R3 = 332Ω, T

C

= -40°C to +85°C, unless

otherwise noted. Typical values are at V

CC

= +5V, V

BBI

= V

BBQ

= 1.4V

P-P

, fIQ= 1MHz, TC= +25°C, unless otherwise noted.) (Notes 1, 2)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Supply Voltage V

CC

V

Total Supply Current I

TOTAL

Pins 3, 13, 15, 31, 33 all connected to V

CC

315 mA

Total Power Dissipation

mW

Note A: Maximum reliable continuous power applied to the baseband differential port is +20dBm from an external 100Ω source.

AC ELECTRICAL CHARACTERISTICS (Modulator)

(MAX2021 Typical Application Circuit, VCC= +4.75V to +5.25V, GND = 0V, I/Q differential inputs driven from a 100Ω DC-coupled
source, 0V common-mode input, P

LO

= 0dBm, 750MHz ≤ fLO≤ 1200MHz, 50Ω LO and RF system impedance, R1 = 432Ω, R2 = 619Ω,

R3 = 332Ω, T

C

= -40°C to +85°C. Typical values are at VCC= +5V, V

BBI

= 1.4V

P-P

differential, V

BBQ

= 1.4V

P-P

differential, fIQ= 1MHz,

f

LO

= 900MHz, TC= +25°C, unless otherwise noted.) (Notes 1, 2)

PARAMETER

CONDITIONS

UNITS

BASEBAND INPUT

Baseb and Input Di fferential Impedance

fIQ = 1MHz 53 Ω

BB Common-Mode Input Voltage
Range

0

V

LO INPUT

LO Input Frequency Range

MHz

LO Input Drive -6 +3

dBm

LO Input Return Loss RF and IF terminated (Note 3) 12 dB

I/Q MIXER OUTPUTS

fLO = 900MHz

Output IP3 OIP3

f

BB1

= 1.8MHz,

f

BB2

= 1.9MHz

f

LO

= 1000MHz

dBm

Output IP2 OIP2

f

BB1

= 1.8MHz,

f

BB2

= 1.9MHz

dBm

Output P1dB

f

BB

= 25MHz,

P

LO

= 0dBm

dBm

Output Power P

OUT

0.7

dBm

Output Power Variation Over
Temperature

T

C

= -40°C to +85°C

dB/°C

Output-Power Flatness

Sweep f

BB

, PRF flatness for fBB from 1MHz

to 50MHz

dB

4.75 5.00 5.25

230 271

1355 1654

SYMBOL

MIN TYP MAX

-3.5

750 1200

-0.016

21.1

22.3

57.9

16.7

0.15

+3.5

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion

750MHz to 1200MHz Quadrature Mod/Demod

_______________________________________________________________________________________ 3

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

RF INPUT

RF Frequency f

RF

750

MHz

Conversion Loss L

C

fBB = 25MHz (Note 7) 9.2 dB

Noise Figure NF fLO = 900MHz 9.3 dB

Noise Figure Under-Blocking

f

BLOCKER

= 900MHz, PRF = 11dBm,

f

RF

= fLO = 890MHz (Note 8)

dB

Input Third-Order Intercept IIP3

f

RF1

= 925MHz, f

RF2

= 926MHz, fLO =

900MHz, P

RF

= PLO = 0dBm, f

SPUR

= 24MHz

dBm

IIP2

f

RF1

= 925MHz, f

RF2

= 926MHz, fLO =

900MHz, P

RF

= PLO = 0dBm, f

SPUR

= 51MHz

76

dBm

Input 1dB Compression P

1dB

fIF = 50MHz, fLO = 900MHz, PLO = 0dBm 30

dBm

I/Q Gain Mismatch fBB = 1MHz, fLO = 900MHz, PLO = 0dBm

dB

PLO = 0dBm 1.1

I/Q Phase Mismatch

f

BB

= 1MHz,

f

LO

= 900MHz

P

LO

= -3dBm

degrees

AC ELECTRICAL CHARACTERISTICS (Demodulator)

(MAX2021 Typical Application Circuit when operated as a demodulator, VCC= +4.75V to +5.25V, GND = 0V, differential baseband out­puts converted to a 50Ω single-ended output, P

RF

= PLO= 0dBm, 750MHz ≤ fLO≤ 1200MHz, 50Ω LO and RF system impedance, R1 =

432Ω, R2 = 619Ω, R3 = 332Ω, T

C

= -40°C to +85°C. Typical values are at VCC= +5V, TC= +25°C, unless otherwise noted.) (Notes 1, 2)

AC ELECTRICAL CHARACTERISTICS (Modulator) (continued)

(MAX2021 Typical Application Circuit, VCC= +4.75V to +5.25V, GND = 0V, I/Q differential inputs driven from a 100Ω DC-coupled
source, 0V common-mode input, P

LO

= 0dBm, 750MHz ≤ fLO≤ 1200MHz, 50Ω LO and RF system impedance, R1 = 432Ω, R2 = 619Ω,

R3 = 332Ω, T

C

= -40°C to +85°C. Typical values are at VCC= +5V, V

BBI

= 1.4V

P-P

differential, V

BBQ

= 1.4V

P-P

differential, fIQ= 1MHz,

f

LO

= 900MHz, TC= +25°C, unless otherwise noted.) (Notes 1, 2)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

ACLR (1st Adjacent Channel
5MHz Offset)

Single-carrier WCDMA (Note 4) 65 dBc

LO Leakage

No external calibration, with each
baseband input terminated in 50Ω

-32

dBm

P

LO

= 0dBm 30

Sideband Suppression

No external calibration,
f

LO

= 920MHz

P

LO

= -3dBm

dBc

Output Noise Density

dBm/Hz

Output Noise Floor P

OUT

= 0dBm, fLO = 900MHz (Note 6)

dBm/Hz

RF Return Loss (Note 3) 15 dB

Note 1: Guaranteed by design and characterization.
Note 2: T

C

is the temperature on the exposed paddle.

Note 3: Parameter also applies to demodulator topology.
Note 4: Single-carrier WCDMA with 10.5dB peak-to-average ratio at 0.1% complementary cumulative distribution function,

P

RF

= -10dBm (PRFis chosen to give -65dBc ACLR).

Note 5: No baseband drive input. Measured with the inputs terminated in 50Ω. At low output levels, the output noise is thermal.
Note 6: The output noise versus P

OUT

curve has the slope of LO noise (Ln dBc/Hz) due to reciprocal mixing.

Note 7: Conversion loss is measured from the single-ended RF input to single-ended combined baseband output.
Note 8: The LO noise (L = 10

(Ln/10)

), determined from the modulator measurements can be used to deduce the noise figure under-

blocking at operating temperature (Tp in Kelvin), F

BLOCK

= 1 + (Lcn - 1) Tp / To + LP

BLOCK

/ (1000kTo), where To = 290K,

P

BLOCK

in mW, k is Boltzmann’s constant = 1.381 x 10

(-23)

J/K, and Lcn = 10

(Lc/10)

, Lc is the conversion loss. Noise figure

under-blocking in dB is NF

BLOCK

= 10 x log (F

BLOCK

). Refer to Application Note 3632.

39.6

43.5

E ach b aseb and inp ut ter mi nated i n 50Ω (N ote 5) -174

-168

1200

NF

BLOCK

17.8

35.2

Input Second-Order Intercept

0.06

0.15

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod

4 _______________________________________________________________________________________

Typical Operating Characteristics

(MAX2021 Typical Application Circuit, VCC= +4.75V to +5.25V, GND = 0V, I/Q differential inputs driven from a 100Ω DC-coupled
source, 0V common-mode input, PLO= 0dBm, 750MHz ≤ fLO≤ 1200MHz, 50Ω LO and RF system impedance, R1 = 432Ω, R2 = 619Ω,
R3 = 332Ω, TC= -40°C to +85°C. Typical values are at VCC= +5V, V

BBI

= 1.4V

P-P

differential, V

BBQ

= 1.4V

P-P

differential, fIQ= 1MHz,

fLO= 900MHz, TC= +25°C, unless otherwise noted.)

TOTAL SUPPLY CURRENT

vs. TEMPERATURE (T

C

)

MAX2021 toc01

TEMPERATURE (°C)

TOTAL SUPPLY CURRENT (mA)

603510-15

220

240

260

280

VCC = 4.75V

VCC = 5.0V

300

200

-40 85

VCC = 5.25V

ACLR vs. OUTPUT POWER PER CARRIER

MAX2021 toc02

OUTPUT POWER PER CARRIER (dBm)

ACLR (dB)

-17-27-37

-78

-76

-74

-72

-70

-68

-66

-64

-62

-60

-80

-47 -7

SINGLE-CARRIER WCDMA

ADJACENT CHANNEL

ALTERNATE CHANNEL

ACLR vs. OUTPUT POWER PER CARRIER

MAX2021 toc03

OUTPUT POWER PER CARRIER (dBm)

ACLR (dB)

-17-27-37

-78

-76

-74

-72

-70

-68

-66

-64

-62

-60

-80

-47 -7

ADJACENT CHANNEL

ALTERNATE CHANNEL

TWO-CARRIER WCDMA

ACLR vs. OUTPUT POWER PER CARRIER

MAX2021 toc04

OUTPUT POWER PER CARRIER (dBm)

ACLR (dB)

-17-27-37

-78

-76

-74

-72

-70

-68

-66

-64

-62

-60

-80

-47 -7

FOUR-CARRIER WCDMA

ADJACENT CHANNEL

ALTERNATE CHANNEL

SIDEBAND SUPPRESSION

vs. LO FREQUENCY

MAX2021 toc05

LO FREQUENCY (MHz)

SIDEBAND SUPPRESSION (dBc)

11251050975900825

20

30

40

50

60

70

10

750 1200

PLO = -3dBm

PLO = -6dBm

PLO = 0dBm

PLO = +3dBm

SIDEBAND SUPPRESSION

vs. LO FREQUENCY

MAX2021 toc06

LO FREQUENCY (MHz)

SIDEBAND SUPPRESSION (dBc)

11251050975900825

20

30

40

50

60

70

10

750 1200

VCC = 4.75V, 5.0V, 5.25V

SIDEBAND SUPPRESSION

vs. LO FREQUENCY

MAX2021 toc07

LO FREQUENCY (MHz)

SIDEBAND SUPPRESSION (dBc)

11251050975900825

20

30

40

50

60

70

10

750 1200

TC = +25°C

TC = +85°C

TC = -40°C

OUTPUT IP3 vs. LO FREQUENCY

MAX2021 toc08

LO FREQUENCY (MHz)

OUTPUT IP3 (dBm)

11251050975900825

15

20

25

30

10

750 1200

TC = -40°C

TC = +85°C

TC = +25°C

PLO = 0dBm, V

CC

= 5.0V

OUTPUT IP3 vs. LO FREQUENCY

MAX2021 toc09

LO FREQUENCY (MHz)

OUTPUT IP3 (dBm)

11251050975900825

15

20

25

30

10

750 1200

VCC = 5.25V

VCC = 5.0V

VCC = 4.75V

TC = +25°C

MODULATOR

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion

750MHz to 1200MHz Quadrature Mod/Demod

_______________________________________________________________________________________ 5

OUTPUT IP3 vs. LO FREQUENCY

MAX2021 toc10

LO FREQUENCY (MHz)

OUTPUT IP3 (dBm)

11251050975900825

15

20

25

30

10

750 1200

PLO = +3dBm

PLO = -3dBm

PLO = -6dBm

PLO = 0dBm

TC = +25°C

OUTPUT IP3

vs. COMMON-MODE VOLTAGE

MAX2021 toc11

COMMON-MODE VOLTAGE (V)

OUTPUT IP3 (dBm)

1.750-1.75

21

22

23

24

25

26

20

-3.50 3.50

fLO = 900MHz, PLO = 0dBm

OUTPUT IP3

vs. COMMON-MODE VOLTAGE

MAX2021 toc12

COMMON-MODE VOLTAGE (V)

OUTPUT IP3 (dBm)

1.750-1.75

21

22

23

24

25

26

20

-3.50 3.50

fLO = 1000MHz

OUTPUT IP2 vs. LO FREQUENCY

MAX2021 toc13

LO FREQUENCY (MHz)

OUTPUT IP2 (dBm)

11251050975900825

50

60

70

80

40

750 1200

TC = +25°C

TC = -40°C

TC = +85°C

OUTPUT IP2 vs. LO FREQUENCY

MAX2021 toc14

LO FREQUENCY (MHz)

OUTPUT IP2 (dBm)

11251050975900825

50

60

70

80

40

750 1200

VCC = 5.0V

VCC = 5.25V

VCC = 4.75V

OUTPUT IP2 vs. LO FREQUENCY

MAX2021 toc15

LO FREQUENCY (MHz)

OUTPUT IP2 (dBm)

11251050975900825

50

60

70

80

40

750 1200

PLO = +3dBm

PLO = -6dBm

PLO = -3dBm

PLO = 0dBm

OUTPUT IP2

vs. COMMON-MODE VOLTAGE

MAX2021 toc16

COMMON-MODE VOLTAGE (V)

OUTPUT IP2 (dBm)

1.750-1.75

60

65

70

75

80

55

-3.50 3.50

fLO = 900MHz

OUTPUT IP2

vs. COMMON-MODE VOLTAGE

MAX2021 toc17

COMMON-MODE VOLTAGE (V)

OUTPUT IP2 (dBm)

1.750-1.75

60

55

65

70

50

-3.50 3.50

fLO = 1000MHz

MODULATOR OUTPUT POWER

vs. INPUT POWER

MAX2021 toc18

INPUT POWER (dBm)

OUTPUT POWER (dBm)

1916 252213

10

5

0

15

20

-5
10 28

INPUT SPLIT BETWEEN I AND Q,
f

IF

= 25MHz, fLO = 900MHz

VCC = 4.75V, 5.0V, 5.25V

Typical Operating Characteristics (continued)

(MAX2021 Typical Application Circuit, VCC= +4.75V to +5.25V, GND = 0V, I/Q differential inputs driven from a 100Ω DC-coupled
source, 0V common-mode input, PLO= 0dBm, 750MHz ≤ fLO≤ 1200MHz, 50Ω LO and RF system impedance, R1 = 432Ω, R2 = 619Ω,
R3 = 332Ω, TC= -40°C to +85°C. Typical values are at VCC= +5V, V

BBI

= 1.4V

P-P

differential, V

BBQ

= 1.4V

P-P

differential, fIQ= 1MHz,

fLO= 900MHz, TC= +25°C, unless otherwise noted.)

MODULATOR

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod

6 _______________________________________________________________________________________

MODULATOR OUTPUT POWER

vs. INPUT POWER

MAX2021 toc19

INPUT POWER (dBm)

OUTPUT POWER (dBm)

1916 252213

10

5

0

15

20

-5
10 28

INPUT SPLIT BETWEEN I AND Q,
f

IF

= 25MHz, fLO = 900MHz

PLO = -6dBm, -3dBm, 0dBm, +3dBm

MODULATOR OUTPUT POWER

vs. LO FREQUENCY

MAX2021 toc20

LO FREQUENCY (MHz)

OUTPUT POWER (dBm)

975900 11251050825

1

-1

-3

3

5

-5

750 1200

TC = -40°C

TC = +85°C

TC = +25°C

V

BBI

= V

BBQ

= 1.4V

P-P

DIFFERENTIAL

LO LEAKAGE vs. LO FREQUENCY

MAX2021 toc21

LO FREQUENCY (MHz)

LO LEAKAGE (dBm)

959948937926

-90

-80

-70

-60

-50

-40

-100
915 970

PRF = -40dBm

PRF = -7dBm

PRF = -1dBm

LO LEAKAGE NULLED AT PRF = -1dBm

PRF = +5dBm

LO LEAKAGE vs. LO FREQUENCY

MAX2021 toc22

LO FREQUENCY (MHz)

LO LEAKAGE (dBm)

959948937926

-90

-80

-70

-60

-50

-40

-100
915 970

TC = -40°C

TC = +85°C

TC = +25°C

PRF = -1dBm, LO LEAKAGE NULLED AT TC = +25°C

LO LEAKAGE vs. LO FREQUENCY

MAX2021 toc23

LO FREQUENCY (MHz)

LO LEAKAGE (dBm)

959948937926

-90

-80

-70

-60

-50

-40

-100
915 970

PLO = -6dBm

PLO = +3dBm

PLO = -3dBm

PLO = 0dBm

PRF = -1dBm, LO LEAKAGE NULLED AT PLO = 0dBm

OUTPUT NOISE vs. OUTPUT POWER

MAX2021 toc24

OUTPUT POWER (dBm)

OUTPUT NOISE (dBm/Hz)

1050-5-10

-175

-170

-165

-160

-155

-150

-180

-15 15

TC = +25°C, fLO = 900MHz

PLO = -6dBm

PLO = -3dBm

PLO = 0dBm

PLO = +3dBm

OUTPUT NOISE vs. OUTPUT POWER

MAX2021 toc25

OUTPUT POWER (dBm)

OUTPUT NOISE (dBm/Hz)

1050-5-10

-175

-170

-165

-160

-155

-150

-180

-15 15

PLO = 0dBm, fLO = 900MHz

TC = +85°C

TC = -40°C

TC = +25°C

Typical Operating Characteristics (continued)

(MAX2021 Typical Application Circuit, VCC= +4.75V to +5.25V, GND = 0V, I/Q differential inputs driven from a 100Ω DC-coupled
source, 0V common-mode input, PLO= 0dBm, 750MHz ≤ fLO≤ 1200MHz, 50Ω LO and RF system impedance, R1 = 432Ω, R2 = 619Ω,
R3 = 332Ω, TC= -40°C to +85°C. Typical values are at VCC= +5V, V

BBI

= 1.4V

P-P

differential, V

BBQ

= 1.4V

P-P

differential, fIQ= 1MHz,

fLO= 900MHz, TC= +25°C, unless otherwise noted.)

MODULATOR

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion

750MHz to 1200MHz Quadrature Mod/Demod

_______________________________________________________________________________________ 7

DEMODULATOR CONVERSION LOSS

vs. LO FREQUENCY

MAX2021 toc26

LO FREQUENCY (MHz)

DEMODULATOR CONVERSION LOSS (dB)

975900 11251050825

10

9

8

11

12

7

750 1200

PLO = 0dBm, VCC = 5.0V

TC = +85°C

TC = +25°C

TC = -40°C

DEMODULATOR INPUT IP3

vs. LO FREQUENCY

MAX2021 toc27

LO FREQUENCY (MHz)

DEMODULATOR INPUT IP3 (dBm)

975900 11251050825

36

34

32

38

40

30

750 1200

PLO = 0dBm, TC = +25°C

VCC = 4.75V

VCC = 5.25V

VCC = 5.0V

DEMODULATOR INPUT IP3

vs. LO FREQUENCY

MAX2021 toc28

LO FREQUENCY (MHz)

DEMODULATOR INPUT IP3 (dBm)

975900 11251050825

36

34

32

38

40

30

750 1200

PLO = 0dBm, VCC = 5.0V

TC = +85°C

TC = +25°C

TC = -40°C

DEMODULATOR INPUT IP2

vs. LO FREQUENCY

MAX2021 toc29

LO FREQUENCY (MHz)

DEMODULATOR INPUT IP2 (dBm)

11251050975900825

60

70

80

90

50

750 1200

TC = -40°C

TC = +85°C

TC = +25°C

PLO = 0dBm, V

CC

= 5.0V

DEMODULATOR PHASE IMBALANCE

vs. LO FREQUENCY

MAX2021 toc30

DEMODULATOR PHASE IMBALANCE (deg)

-8

-6

-4

-2

0

2

4

6

8

10

-10

LO FREQUENCY (MHz)

11251050975900825750 1200

PLO = -3dBm

PLO = 0dBm

PLO = +3dBm

PLO = -6dBm

MAX2021 toc31

-0.15

-0.10

-0.05

0

0.05

0.10

0.15

0.20

-0.20

DEMODULATOR AMPLITUDE IMBALANCE

vs. LO FREQUENCY

DEMODULATOR AMPLITUDE IMBALANCE (dB)

LO FREQUENCY (MHz)

11251050975900825750 1200

PLO = -6dBm, -3dBm, 0dBm, +3dBm

Typical Operating Characteristics

(MAX2021 Typical Application Circuit, VCC= +4.75V to +5.25V, GND = 0V, I/Q differential inputs driven from a 100Ω DC-coupled
source, 0V common-mode input, PRF= 5dBm, PLO= 0dBm, 750MHz ≤ fLO≤ 1200MHz, 50Ω LO and RF system impedance, R1 = 432Ω,
R2 = 619Ω, R3 = 332Ω, TC= -40°C to +85°C. Typical values are at VCC= +5V, fLO= 900MHz, TC= +25°C, unless otherwise noted.)

LO PORT RETURN LOSS

vs. LO FREQUENCY

MAX2021 toc32

LO FREQUENCY (MHz)

LO PORT RETURN LOSS (dB)

975900 11251050825

+10

+15

+20

+5

0

+25

750 1200

PLO = -6dBm, -3dBm

PLO = +3dBm

PLO = 0dBm

RF PORT RETURN LOSS

vs. LO FREQUENCY

MAX2021 toc33

LO FREQUENCY (MHz)

RF PORT RETURN LOSS (dB)

11301035940845

+40

+35

+30

+25

+20

+15

+10

+5

0

+45

750 1225

PLO = -6dBm, -3dBm, 0dBm, +3dBm

IF FLATNESS

vs. BASEBAND FREQUENCY

MAX2021 toc34

BASEBAND FREQUENCY (MHz)

IF OUTPUT POWER (dBm)

706010 20 30 40 50

-11

-10

-9

-8

-7

-6

-5

-4

-12
080

fLO = 1000MHz

fLO = 900MHz

PLO = 0dBm

DEMODULATOR

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod

8 _______________________________________________________________________________________

Detailed Description

The MAX2021 is designed for upconverting differential
in-phase (I) and quadrature (Q) inputs from baseband
to a 750MHz to 1200MHz RF frequency range. The
device can also be used as a demodulator, downcon­verting an RF input signal directly to baseband.
Applications include RFID handheld and portal readers,
as well as single and multicarrier GSM/EDGE,
cdma2000, WCDMA, and iDEN base stations. Direct
conversion architectures are advantageous since they
significantly reduce transmitter or receiver cost, part
count, and power consumption as compared to tradition­al IF-based double conversion systems.

The MAX2021 integrates internal baluns, an LO buffer, a
phase splitter, two LO driver amplifiers, two matched
double-balanced passive mixers, and a wideband
quadrature combiner. The MAX2021’s high-linearity mix­ers, in conjunction with the part’s precise in-phase and
quadrature channel matching, enable the device to pos­sess excellent dynamic range, ACLR, 1dB compression

point, and LO and sideband suppression characteris­tics. These features make the MAX2021 ideal for four­carrier WCDMA operation.

LO Input Balun, LO Buffer, and

Phase Splitter

The MAX2021 requires a single-ended LO input, with a
nominal power of 0dBm. An internal low-loss balun at
the LO input converts the single-ended LO signal to a
differential signal at the LO buffer input. In addition, the
internal balun matches the buffer’s input impedance to
50Ω over the entire band of operation.

The output of the LO buffer goes through a phase split­ter, which generates a second LO signal that is shifted
by 90° with respect to the original. The 0° and 90° LO
signals drive the I and Q mixers, respectively.

LO Driver

Following the phase splitter, the 0° and 90° LO signals
are each amplified by a two-stage amplifier to drive the
I and Q mixers. The amplifier boosts the level of the LO

Pin Description

PIN NAME FUNCTION

1, 5, 9–12, 14, 16–19, 22,

24, 27–30, 32, 34, 35, 36

GND Ground

2

3rd LO Amplifier Bias. Connect a 332Ω resistor to ground.

3

LO Input Buffer Amplifier Supply Voltage. Bypass to GND with 33pF and 0.1µF
capacitors as close to the pin as possible.

4 LO Local Oscillator Input. 50Ω input impedance.

6

1st LO Input Buffer Amplifier Bias. Connect a 432Ω resistor to ground.

7 N.C. No Connection. Leave unconnected.

8

2nd LO Amplifier Bias. Connect a 619Ω resistor to ground.

13

I-Channel 1st LO Amplifier Supply Voltage. Bypass to GND with 33pF and 0.1µF
capacitors as close to the pin as possible.

15

I-Channel 2nd LO Amplifier Supply Voltage. Bypass to GND with 33pF and 0.1µF
capacitors as close to the pin as possible.

20 BBI+ Baseband In-Phase Noninverting Port

21 BBI- Baseband In-Phase Inverting Port

23 RF RF Port

25 BBQ- Baseband Quadrature Inverting Port

26 BBQ+ Baseband Quadrature Noninverting Port

31

Q-Channel 2nd LO Amplifier Supply Voltage. Bypass to GND with 33pF and 0.1µF
capacitors as close to the pin as possible.

33

Q-Channel 1st LO Amplifier Supply Voltage. Bypass to GND with 33pF and 0.1µF
capacitors as close to the pin as possible.

EP GND

Exposed Ground Paddle. The exposed paddle MUST be soldered to the ground plane
using multiple vias.

RBIASLO3

VCCLOA

RBIASLO1

RBIASLO2

VCCLOI1

VCCLOI2

VCCLOQ2

VCCLOQ1

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion

750MHz to 1200MHz Quadrature Mod/Demod

signals to compensate for any changes in LO drive lev­els. The two-stage LO amplifier allows a wide input
power range for the LO drive. The MAX2021 can toler­ate LO level swings from -6dBm to +3dBm.

I/Q Modulator

The MAX2021 modulator is composed of a pair of
matched double-balanced passive mixers and a balun.
The I and Q differential baseband inputs accept signals
from DC to 300MHz with differential amplitudes up to
4V

P-P

. The wide input bandwidths allow operation of the
MAX2021 as either a direct RF modulator or as an
image-reject mixer. The wide common-mode compli­ance range allows for direct interface with the base­band DACs. No active buffer circuitry is required
between the baseband DACs and the MAX2021 for
cdma2000 and WCDMA applications.

The I and Q signals directly modulate the 0° and 90° LO
signals and are upconverted to the RF frequency. The out­puts of the I and Q mixers are combined through a balun
to produce a singled-ended RF output.

Applications Information

LO Input Drive

The LO input of the MAX2021 is internally matched to
50Ω, and requires a single-ended drive at a 750MHz to
1200MHz frequency range. An integrated balun con­verts the singled-ended input signal to a differential sig­nal at the LO buffer differential input. An external
DC-blocking capacitor is the only external part required
at this interface. The LO input power should be within
the -6dBm to +3dBm range. An LO input power of

-3dBm is recommended for best overall peformance.

Baseband I/Q Input Drive

Drive the MAX2021 I and Q baseband inputs differen­tially for best performance. The baseband inputs have
a 53Ω differential input impedance. The optimum
source impedance for the I and Q inputs is 100Ω differ­ential. This source impedance achieves the optimal sig­nal transfer to the I and Q inputs, and the optimum
output RF impedance match. The MAX2021 can accept
input power levels of up to +20dBm on the I and Q
inputs. Operation with complex waveforms, such as
CDMA carriers or GSM signals, utilize input power lev­els that are far lower. This lower power operation is
made necessary by the high peak-to-average ratios of
these complex waveforms. The peak signals must be
kept below the compression level of the MAX2021. The
input common-mode voltage should be confined to the

-3.5V to +3.5V DC range.

The MAX2021 is designed to interface directly with
Maxim high-speed DACs. This generates an ideal total

transmitter lineup, with minimal ancillary circuit elements.
Such DACs include the MAX5875 series of dual DACs,
and the MAX5895 dual interpolating DAC. These DACs
have ground-referenced differential current outputs.
Typical termination of each DAC output into a 50Ω load
resistor to ground, and a 10mA nominal DC output cur­rent results in a 0.5V common-mode DC level into the
modulator I/Q inputs. The nominal signal level provided
by the DACs will be in the -12dBm range for a single
CDMA or WCDMA carrier, reducing to -18dBm per car­rier for a four-carrier application.

The I/Q input bandwidth is greater than 50MHz at

-0.1dB response. The direct connection of the DAC to
the MAX2021 ensures the maximum signal fidelity, with
no performance-limiting baseband amplifiers required.
The DAC output can be passed through a lowpass filter
to remove the image frequencies from the DAC’s output
response. The MAX5895 dual interpolating DAC can be
operated at interpolation rates up to x8. This has the
benefit of moving the DAC image frequencies to a very
high, remote frequency, easing the design of the base­band filters. The DAC’s output noise floor and interpola­tion filter stopband attenuation are sufficiently good to
ensure that the 3GPP noise floor requirement is met for
large frequency offsets, 60MHz for example, with no fil­tering required on the RF output of the modulator.

Figure 1 illustrates the ease and efficiency of interfacing
the MAX2021 with a Maxim DAC, in this case the
MAX5895 dual 16-bit interpolating-modulating DAC.

MAX5895

DUAL 16-BIT INTERP DAC

RF MODULATOR

I/Q GAIN AND

OFFSET ADJUST

BBI

LO

BBQ

FREQ

50Ω

50Ω

FREQ

50Ω

50Ω

0°

90°

∑

MAX2021

Figure 1. MAX5895 DAC Interfaced with MAX2021

_______________________________________________________________________________________________________ 9

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod

10 ______________________________________________________________________________________

MAX2021MAX2021

The MAX5895 DAC has programmable gain and differ­ential offset controls built in. These can be used to opti­mize the LO leakage and sideband suppression of the
MAX2021 quadrature modulator.

RF Output

The MAX2021 utilizes an internal passive mixer archi­tecture that enables the device to possess an excep­tionally low-output noise floor. With such architectures,
the total output noise is typically a power summation of
the theoretical thermal noise (KTB) and the noise contri­bution from the on-chip LO buffer circuitry. As demon­strated in the Typical Operating Characteristics, the
MAX2021’s output noise approaches the thermal limit
of -174dBm/Hz for lower output power levels. As the
output power increases, the noise level tracks the noise
contribution from the LO buffer circuitry, which is
approximately -168dBc/Hz.

The I/Q input power levels and the insertion loss of the
device determine the RF output power level. The input
power is a function of the delivered input I and Q volt­ages to the internal 50Ω termination. For simple sinu­soidal baseband signals, a level of 89mV

P-P

differential

on the I and the Q inputs results in a -17dBm input
power level delivered to the I and Q internal 50Ω termi-
nations. This results in an RF output power of -23.2dBm.

External Diplexer

LO leakage at the RF port can be nulled to a level less
than -80dBm by introducing DC offsets at the I and Q
ports. However, this null at the RF port can be compro-

mised by an improperly terminated I/Q IF interface. Care
must be taken to match the I/Q ports to the driving DAC
circuitry. Without matching, the LO’s second-order (2fLO)
term may leak back into the modulator’s I/Q input port
where it can mix with the internal LO signal to produce
additional LO leakage at the RF output. This leakage
effectively counteracts against the LO nulling. In addi­tion, the LO signal reflected at the I/Q IF port produces a
residual DC term that can disturb the nulling condition.

As demonstrated in Figure 2, providing an RC termination
on each of the I+, I-, Q+, Q- ports reduces the amount of
LO leakage present at the RF port under varying temper­ature, LO frequency, and baseband drive conditions. See
the Typical Operating Characteristics for details. Note
that the resistor value is chosen to be 100Ω with a corner
frequency 1 / (2πRC) selected to adequately filter the f

LO

and 2fLOleakage, yet not affecting the flatness of the
baseband response at the highest baseband frequency.
The common-mode fLOand 2fLOsignals at I+/I- and
Q+/Q- effectively see the RC networks and thus become
terminated in 50Ω (R/2). The RC network provides a path
for absorbing the 2fLOand fLOleakage, while the induc­tor provides high impedance at fLOand 2fLOto help the
diplexing process.

RF Demodulator

The MAX2021 can also be used as an RF demodulator,
downconverting an RF input signal directly to base­band. The single-ended RF input accepts signals from
750MHz to 1200MHz with power levels up to +30dBm.
The passive mixer architecture produces a conversion
loss of typically 9.2dB. The downconverter is optimized
for high linearity and excellent noise performance, typi­cally with a +35.2dBm IIP3, a P1dB of greater than
+30dBm, and a 9.3dB noise figure.

A wide I/Q port bandwidth allows the port to be used as
an image-reject mixer for downconversion to a quadra­ture IF frequency.

The RF and LO inputs are internally matched to 50Ω.
Thus, no matching components are required, and only
DC-blocking capacitors are needed for interfacing.

Power Scaling with Changes

to the Bias Resistors

Bias currents for the LO buffers are optimized by fine
tuning resistors R1, R2, and R3. Maxim recommends
using ±1%-tolerant resistors; however, standard ±5%
values can be used if the ±1% components are not
readily available. The resistor values shown in the
Typical Application Circuit were chosen to provide
peak performance for the entire 750MHz to 1200MHz
band. If desired, the current can be backed off from
this nominal value by choosing different values for R1,

RF-MODULATOR

LO

100Ω

100Ω

L = 40nH

C = 6.8pF

∑

L = 40nH

I

Q

100Ω

100Ω

C = 6.8pF

C = 6.8pF

0°

90°

MAX2021

Figure 2. Diplexer Network Recommended for GSM 900
Transmitter Applications

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion

750MHz to 1200MHz Quadrature Mod/Demod

______________________________________________________________________________________ 11

R2, and R3. Tables 1 and 2 outline the performance
trade-offs that can be expected for various combina­tions of these bias resistors. As noted within the tables,
the performance trade-offs may be more pronounced
for different operating frequencies. Contact the factory
for additional details.

Layout Considerations

A properly designed PC board is an essential part of
any RF/microwave circuit. Keep RF signal lines as short
as possible to reduce losses, radiation, and induc­tance. For the best performance, route the ground pin
traces directly to the exposed pad under the package.
The PC board exposed paddle MUST be connected to
the ground plane of the PC board. It is suggested that
multiple vias be used to connect this pad to the lower­level ground planes. This method provides a good
RF/thermal conduction path for the device. Solder the
exposed pad on the bottom of the device package to
the PC board. The MAX2021 evaluation kit can be used
as a reference for board layout. Gerber files are avail­able upon request at www.maxim-ic.com.

Power-Supply Bypassing

Proper voltage-supply bypassing is essential for high­frequency circuit stability. Bypass all VCC_ pins with

33pF and 0.1µF capacitors placed as close to the pins
as possible. The smallest capacitor should be placed
closest to the device.

To achieve optimum performance, use good voltage­supply layout techniques. The MAX2021 has several RF
processing stages that use the various VCC_ pins, and
while they have on-chip decoupling, off-chip interaction
between them may degrade gain, linearity, carrier sup­pression, and output power-control range. Excessive
coupling between stages may degrade stability.

Exposed Pad RF/Thermal Considerations

The EP of the MAX2021’s 36-pin thin QFN-EP package
provides a low thermal-resistance path to the die. It is
important that the PC board on which the IC is mounted
be designed to conduct heat from this contact. In addi­tion, the EP provides a low-inductance RF ground path
for the device.

The exposed paddle (EP) MUST be soldered to a
ground plane on the PC board either directly or through
an array of plated via holes. An array of 9 vias, in a 3 x
3 array, is suggested. Soldering the pad to ground is
critical for efficient heat transfer. Use a solid ground
plane wherever possible.

Note: VCC= 5V, PLO= 0dBm, TA= +25°C, I/Q voltage levels = 1.4V

P-P

differential.

LO FREQ

(MHz)

RF FREQ

(MHz)

R1

(ΩΩΩΩ)

R2

(ΩΩΩΩ)

R3

(ΩΩΩΩ)

I

CC

(mA)

OIP3

(dBm)

LO LEAK

(dBm)

IMAGE REJ

(dBc)

OIP2

(dBm)

420 620 330 271 19.6 -32.1 23.9 50.5

453 665 360 253 21.9 -32.7 34.0 51.0

499 698 402 229 18.9 -33.7 30.0 52.6

549 806 464 205 15.7 -34.4 23.7 46.0

800 801.8

650 1000 550 173 13.6 -34.2 23.3 32.3

420 620 330 271 20.7 -31.4 43.4 54.0

453 665 360 253 21.6 -31.6 42.4 55.4

499 698 402 229 20.6 -31.8 42.7 59.8

549 806 464 205 19.0 -31.9 40.3 50.7

900 901.8

650 1000 550 173 14.9 -30.5 25.0 34.6

420 620 330 271 22.4 -32.8 39.3 55.5

453 665 360 253 22.2 -33.2 39.1 56.3

499 698 402 229 19.9 -33.8 43.5 55.0

549 806 464 205 17.6 -34.8 40.5 51.4

1000

650 1000 550 173 14.6 -33.9 36.8 32.8

Table 1. Typical Performance Trade-Offs as a Function of Current Draw—Modulator Mode

1001.8

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod

12 ______________________________________________________________________________________

LO FREQ

(MHz)

RF FREQ

(MHz)

R1

(ΩΩΩΩ)

R2
(ΩΩΩΩ)

R3

(ΩΩΩΩ)

I

CC

(mA)

C O N VER SIO N

L O SS ( d B )

IIP3

(dBm)

57MHz IIP2

(dBm)

420 620 330 269 9.8 33.85 62.1

453 665 360 254 9.83 33.98 62.9

499 698 402 230 9.81 32.2 66.6

549 806 464 207 9.84 31.1 66.86

800 771

650 1000 550 173 9.95 29.87 65.25

420 620 330 269 9.21 33.1 68

453 665 360 254 9.25 33.9 66.87

499 698 402 230 9.36 34.77 66.7

549 806 464 207 9.39 35.3 66.6

900 871

650 1000 550 173 9.46 32 64.64

420 620 330 269 9.47 34.9 > 77.7

453 665 360 254 9.5 35.4 > 77.5

499 698 402 230 9.53 34.58 > 76.5

549 806 464 207 9.5 33.15 > 76.5

1000 971

650 1000 550 173 9.61 31.5 76

Table 2. Typical Performance Trade-Offs as a Function of Current Draw—Demodulator Mode

Note: Used on PC board 180° combiners and off PC board quadrature combiner with VCC= 5V, PRF= -3dBm, P

LO

= 0dBm, TA = +25°C,

IF1 = 28MHz, IF2 = 29MHz.

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion

750MHz to 1200MHz Quadrature Mod/Demod

______________________________________________________________________________________ 13

MAX2021

1

2

3

4

5

6

7

8

9

10

11 12

13 14

THIN QFN

15

16 17

18

27

26

25

24

23

22

21

20

19

36

35

34

33 32

31

30 29

28

Σ

BIAS

LO2

BIAS

LO1

90°

0°

BIAS

LO3

GND

BBI+

BBI-

GND

RF

GND

BBQ-

BBQ+

GND

GND

GND

GND

GND

GND

GND

GND

GND

GND

RBIASLO3

VCCLOA

LO

GND

RBIASLO1

N.C.

RBIASLO2

GND

GND

GND

VCCLOQ2

GND

GND

GND

GND

MAX2021

VCCLOI1

VCCLOI2

VCCLOQ1

Pin Configuration/Functional Diagram

1

2

3

4

5

6

7

8

9

10

11 12

13 14 15

16 17

18

27

26

25

24

23

22

21

20

19

36

35

34

33 32

31

30 29

28

Σ

BIAS

LO2

BIAS

LO1

90°

0°

BIAS

LO3

GND

BBI+

BBI-

GND

RF

RF

GND

BBQ-

BBQ+

Q+

Q-

GND

I-

I+

C9

8.2pF

C8

0.1μF

V

CC

C7
33pF

C5

0.1μF

C6

33pF

V

CC

GND

GND

GND

GND

VCCLOI1

VCCLOI2

GND

GND

GND

GND

GND

RBIASLO3

R3

332Ω

C1
33pF

C3
82pF

C2

0.1μF

V

CC

VCCLOA

LO

GND

RBIASLO1

R1

432Ω

N.C.

RBIASLO2

C11

0.1μF
V

CC

C10
33pF

C12

0.1μF

C13

33pF

V

CC

GND

GND

GND

VCCLOQ2

GND

GND

GND

GND

MAX2021

VCCLOQ1

R2

619Ω

Typical Application Circuit

MAX2021

High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod

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.

14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 2006 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

COMPONENT VALUE DESCRIPTION

C1, C6, C7, C10, C13 33pF 33pF ±5%, 50V C0G ceramic capacitors (0402)

C2, C5, C8, C11, C12 0.1µF 0.1µF ±10%, 16V X7R ceramic capacitors (0603)

C3 82pF 82pF ±5%, 50V C0G ceramic capacitor (0402)

C9 8.2pF 8.2pF ±0.1pF, 50V C0G ceramic capacitor (0402)

R1 432Ω 432Ω ±1% resistor (0402)

R2 619Ω 619Ω ±1% resistor (0402)

R3 332Ω 332Ω ±1% resistor (0402)

Table 3. Component List Referring to the Typical Application Circuit

Package Information

For the latest package outline information, go to

www.maxim-ic.com/packages

.

Chip Information

PROCESS: SiGe BiCMOS