MAXIM MAX2021ETX

19-3918; Rev 0; 3/06
ILABLE
N KIT AVA
EVALUATIO
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
Features
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.
♦ 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 OP1dB
♦ -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:
Single and Multicarrier WCDMA 850 Base Stations
♦ +35.2dBm Typical IIP3
♦ +76dBm Typical IIP2
♦ > 30dBm IP1dB
♦ 9.2dB Typical Conversion Loss
♦ 9.3dB Typical NF
Single and Multicarrier cdmaOne™ and cdma2000
Base Stations
♦ 0.06dB Typical I/Q Gain Imbalance
♦ 0.15° I/Q Typical Phase Imbalance
Applications
RFID Handheld and Portal Readers
GSM 850/GSM 900 EDGE Base Stations
Predistortion Transmitters and Receivers
Ordering Information
WiMAX Transmitters and Receivers
PIN-PACKAGE
MAX2021ETX
-40°C to +85°C
36 Thin QFN-EP*
T3666-2
(6mm x 6mm)
Digital and Spread-Spectrum Communication
Systems
MAX2021ETX-T
-40°C to +85°C
36 Thin QFN-EP*
T3666-2
(6mm x 6mm)
Video-on-Demand (VOD) and DOCSIS Compliant
Edge QAM Modulation
MAX2021ETX+
-40°C to +85°C
36 Thin QFN-EP*
T3666-2
(6mm x 6mm)
Cable Modem Termination Systems (CMTS)
MAX2021ETX+T -40°C to +85°C
36 Thin QFN-EP*
T3666-2
(6mm x 6mm)
Military Systems
Microwave Links
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.
PART
PKG
CODE
TEMP RANGE
Fixed Broadband Wireless Access
*EP = Exposed paddle. + = Lead free.
-T = Tape-and-reel package.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX2021
General Description
MAX2021
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
ABSOLUTE MAXIMUM RATINGS
VCC_ to GND ........................................................-0.3V to +5.5V
BBI+, BBI-, BBQ+, BBQ- to GND...............-3.5V to (VCC + 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
θJA (2.5m/s air flow) .........................................................28°C/W
θJC (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
Note A: Maximum reliable continuous power applied to the baseband differential port is +20dBm from an external 100Ω source.
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.
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, TC = -40°C to +85°C, unless
otherwise noted. Typical values are at VCC = +5V, VBBI = VBBQ = 1.4VP-P, fIQ = 1MHz, TC = +25°C, unless otherwise noted.) (Notes 1, 2)
PARAMETER
Supply Voltage
Total Supply Current
SYMBOL
CONDITIONS
VCC
ITOTAL
Pins 3, 13, 15, 31, 33 all connected to VCC
MIN
TYP
MAX
UNITS
4.75
5.00
5.25
V
230
Total Power Dissipation
271
315
mA
1355
1654
mW
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, 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, VBBI = 1.4VP-P differential, VBBQ = 1.4VP-P differential, fIQ = 1MHz,
fLO = 900MHz, TC = +25°C, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
BASEBAND INPUT
Baseband Input Differential Impedance
fIQ = 1MHz
Ω
53
BB Common-Mode Input Voltage
Range
-3.5
0
+3.5
V
1200
MHz
+3
dBm
LO INPUT
LO Input Frequency Range
750
LO Input Drive
-6
LO Input Return Loss
RF and IF terminated (Note 3)
12
dB
I/Q MIXER OUTPUTS
fLO = 900MHz
21.1
fLO = 1000MHz
22.3
Output IP3
OIP3
fBB1 = 1.8MHz,
fBB2 = 1.9MHz
Output IP2
OIP2
fBB1 = 1.8MHz,
fBB2 = 1.9MHz
57.9
dBm
fBB = 25MHz,
PLO = 0dBm
16.7
dBm
0.7
dBm
-0.016
dB/°C
0.15
dB
Output P1dB
Output Power
POUT
Output Power Variation Over
Temperature
TC = -40°C to +85°C
Output-Power Flatness
Sweep fBB, PRF flatness for fBB from 1MHz
to 50MHz
2
_______________________________________________________________________________________
dBm
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
(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, VBBI = 1.4VP-P differential, VBBQ = 1.4VP-P differential, fIQ = 1MHz,
fLO = 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
Sideband Suppression
No external calibration,
fLO = 920MHz
Output Noise Density
Each baseband input terminated in 50Ω (Note 5)
-174
dBm/Hz
Output Noise Floor
POUT = 0dBm, fLO = 900MHz (Note 6)
-168
dBm/Hz
RF Return Loss
(Note 3)
15
dB
PLO = 0dBm
30
PLO = -3dBm
39.6
dBc
43.5
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, PRF = 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, TC = +25°C, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
1200
MHz
RF INPUT
RF Frequency
fRF
Conversion Loss
LC
Noise Figure
NF
Noise Figure Under-Blocking
NFBLOCK
750
fBB = 25MHz (Note 7)
9.2
dB
fLO = 900MHz
9.3
dB
fBLOCKER = 900MHz, PRF = 11dBm,
fRF = fLO = 890MHz (Note 8)
17.8
dB
Input Third-Order Intercept
IIP3
fRF1 = 925MHz, fRF2 = 926MHz, fLO =
900MHz, PRF = PLO = 0dBm, fSPUR = 24MHz
35.2
dBm
Input Second-Order Intercept
IIP2
fRF1 = 925MHz, fRF2 = 926MHz, fLO =
900MHz, PRF = PLO = 0dBm, fSPUR = 51MHz
76
dBm
Input 1dB Compression
P1dB
fIF = 50MHz, fLO = 900MHz, PLO = 0dBm
30
dBm
I/Q Gain Mismatch
fBB = 1MHz, fLO = 900MHz, PLO = 0dBm
0.06
dB
I/Q Phase Mismatch
fBB = 1MHz,
fLO = 900MHz
PLO = 0dBm
1.1
PLO = -3dBm
0.15
degrees
Note 1: Guaranteed by design and characterization.
Note 2: TC 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,
PRF = -10dBm (PRF is 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 POUT 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 underblocking at operating temperature (Tp in Kelvin), FBLOCK = 1 + (Lcn - 1) Tp / To + LPBLOCK / (1000kTo), where To = 290K,
PBLOCK 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 NFBLOCK = 10 x log (FBLOCK). Refer to Application Note 3632.
_______________________________________________________________________________________
3
MAX2021
AC ELECTRICAL CHARACTERISTICS (Modulator) (continued)
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, VBBI = 1.4VP-P differential, VBBQ = 1.4VP-P differential, fIQ = 1MHz,
fLO = 900MHz, TC = +25°C, unless otherwise noted.)
MODULATOR
-62
-64
-64
VCC = 5.0V
240
VCC = 4.75V
220
-40
-15
10
35
60
-70
-72
-70
-72
-74
-74
-76
-76
85
-78
SINGLE-CARRIER WCDMA
-47
-37
ALTERNATE CHANNEL
-80
-27
-17
TWO-CARRIER WCDMA
-47
-7
-37
-27
-7
-17
OUTPUT POWER PER CARRIER (dBm)
ACLR vs. OUTPUT POWER PER CARRIER
SIDEBAND SUPPRESSION
vs. LO FREQUENCY
SIDEBAND SUPPRESSION
vs. LO FREQUENCY
-68
ALTERNATE CHANNEL
-72
-74
-76
50
40
30
PLO = 0dBm
750
-7
825
975
1050
1125
750
1200
825
OUTPUT IP3 vs. LO FREQUENCY
PLO = 0dBm, VCC = 5.0V
TC = -40°C
50
40
TC = +25°C
975
1050
1125
1200
OUTPUT IP3 vs. LO FREQUENCY
30
TC = +25°C
VCC = 5.25V
25
TC = +25°C
OUTPUT IP3 (dBm)
OUTPUT IP3 (dBm)
25
900
LO FREQUENCY (MHz)
30
MAX2021 toc07
TC = +85°C
20
TC = +85°C
15
20
VCC = 4.75V, 5.0V, 5.25V
30
LO FREQUENCY (MHz)
SIDEBAND SUPPRESSION
vs. LO FREQUENCY
70
900
MAX2021 toc08
-17
OUTPUT POWER PER CARRIER (dBm)
30
40
10
10
-27
60
50
PLO = +3dBm
FOUR-CARRIER WCDMA
-37
60
20
20
-47
MAX2021 toc06
PLO = -6dBm
PLO = -3dBm
MAX2021 toc09
-70
60
70
SIDEBAND SUPPRESSION (dBc)
-66
SIDEBAND SUPPRESSION (dBc)
MAX2021 toc04
ADJACENT CHANNEL
-64
70
MAX2021 toc05
OUTPUT POWER PER CARRIER (dBm)
-62
-80
ALTERNATE CHANNEL
-68
TEMPERATURE (°C)
-60
-78
ADJACENT CHANNEL
-68
-80
ADJACENT CHANNEL
-66
ACLR (dB)
ACLR (dB)
260
-78
ACLR (dB)
-62
-66
200
20
VCC = 5.0V
VCC = 4.75V
15
TC = -40°C
10
10
750
825
900
975
1050
LO FREQUENCY (MHz)
4
-60
MAX2021 toc02
VCC = 5.25V
280
ACLR vs. OUTPUT POWER PER CARRIER
ACLR vs. OUTPUT POWER PER CARRIER
-60
MAX2021 toc01
TOTAL SUPPLY CURRENT (mA)
300
MAX2021 toc03
TOTAL SUPPLY CURRENT
vs. TEMPERATURE (TC)
SIDEBAND SUPPRESSION (dBc)
MAX2021
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
1125
1200
10
750
825
900
975
1050
LO FREQUENCY (MHz)
1125
1200
750
825
900
975
1050
LO FREQUENCY (MHz)
_______________________________________________________________________________________
1125
1200
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
MODULATOR
OUTPUT IP3
vs. COMMON-MODE VOLTAGE
PLO = 0dBm
PLO = -6dBm
fLO = 1000MHz
25
24
23
22
21
825
900
975
1050
1125
0
1.75
3.50
MAX2021 toc13
80
TC = -40°C
VCC = 5.25V
VCC = 5.0V
50
50
975
1050
1125
40
750
1200
825
900
975
1050
1125
1200
750
825
900
975
1050
1125
LO FREQUENCY (MHz)
LO FREQUENCY (MHz)
LO FREQUENCY (MHz)
OUTPUT IP2
vs. COMMON-MODE VOLTAGE
OUTPUT IP2
vs. COMMON-MODE VOLTAGE
MODULATOR OUTPUT POWER
vs. INPUT POWER
75
fLO = 1000MHz
70
65
60
55
60
55
0
1.75
COMMON-MODE VOLTAGE (V)
3.50
INPUT SPLIT BETWEEN I AND Q,
fIF = 25MHz, fLO = 900MHz
15
10
5
VCC = 4.75V, 5.0V, 5.25V
0
-5
50
-1.75
20
OUTPUT POWER (dBm)
OUTPUT IP2 (dBm)
65
1200
MAX2021 toc18
fLO = 900MHz
MAX2021 toc17
70
MAX2021 toc16
80
-3.50
PLO = 0dBm
PLO = -3dBm
40
900
PLO = -6dBm
60
VCC = 4.75V
40
825
PLO = +3dBm
50
TC = +85°C
3.50
1.75
OUTPUT IP2 vs. LO FREQUENCY
70
60
0
80
OUTPUT IP2 (dBm)
OUTPUT IP2 (dBm)
TC = +25°C
60
-1.75
COMMON-MODE VOLTAGE (V)
70
70
OUTPUT IP2 (dBm)
-3.50
OUTPUT IP2 vs. LO FREQUENCY
OUTPUT IP2 vs. LO FREQUENCY
80
OUTPUT IP2 (dBm)
-1.75
COMMON-MODE VOLTAGE (V)
LO FREQUENCY (MHz)
750
22
20
-3.50
1200
MAX2021 toc14
750
23
21
20
10
24
MAX2021 toc15
20
15
25
OUTPUT IP3 (dBm)
OUTPUT IP3 (dBm)
PLO = +3dBm
fLO = 900MHz, PLO = 0dBm
OUTPUT IP3 (dBm)
PLO = -3dBm
26
MAX2021 toc11
TC = +25°C
25
26
MAX2021 toc10
30
OUTPUT IP3
vs. COMMON-MODE VOLTAGE
MAX2021 toc12
OUTPUT IP3 vs. LO FREQUENCY
-3.50
-1.75
0
1.75
COMMON-MODE VOLTAGE (V)
3.50
10
13
16
19
22
25
28
INPUT POWER (dBm)
_______________________________________________________________________________________
5
MAX2021
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, VBBI = 1.4VP-P differential, VBBQ = 1.4VP-P differential, fIQ = 1MHz,
fLO = 900MHz, TC = +25°C, unless otherwise noted.)
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, VBBI = 1.4VP-P differential, VBBQ = 1.4VP-P differential, fIQ = 1MHz,
fLO = 900MHz, TC = +25°C, unless otherwise noted.)
MODULATOR
MODULATOR OUTPUT POWER
vs. LO FREQUENCY
PLO = -6dBm, -3dBm, 0dBm, +3dBm
0
1
-1
TC = +85°C
TC = +25°C
-3
16
19
22
25
825
LO LEAKAGE vs. LO FREQUENCY
900
975
1050
1125
1200
-40
MAX2021 toc22
-60
TC = +85°C
-80
-90
PLO = -6dBm
PLO = -3dBm
-60
-70
-80
TC = +25°C
926
937
948
PLO = +3dBm
970
-150
TC = +25°C, fLO = 900MHz
-155
915
PLO = -6dBm
PLO = -3dBm
-165
-170
PLO = 0dBm
926
937
-180
948
959
970
-15
-10
-5
MAX2021 toc25
PLO = 0dBm, fLO = 900MHz
-155
-160
-165
TC = +85°C
-170
TC = -40°C
-175
TC = +25°C
-180
-15
-10
-5
0
5
0
5
OUTPUT POWER (dBm)
LO FREQUENCY (MHz)
OUTPUT NOISE (dBm/Hz)
970
-160
OUTPUT NOISE vs. OUTPUT POWER
10
15
OUTPUT POWER (dBm)
6
959
PLO = +3dBm
PLO = 0dBm
LO FREQUENCY (MHz)
-150
948
-175
-100
959
937
OUTPUT NOISE vs. OUTPUT POWER
-90
915
926
LO FREQUENCY (MHz)
PRF = -1dBm, LO LEAKAGE NULLED AT PLO = 0dBm
-50
LO LEAKAGE (dBm)
TC = -40°C
-100
PRF = -1dBm
915
LO LEAKAGE vs. LO FREQUENCY
PRF = -1dBm, LO LEAKAGE NULLED AT TC = +25°C
-70
-80
LO FREQUENCY (MHz)
INPUT POWER (dBm)
-50
PRF = -7dBm
-70
-100
750
28
OUTPUT NOISE (dBm/Hz)
13
MAX2021 toc23
10
-60
-90
-5
-5
-40
-50
MAX2021 toc24
5
LO LEAKAGE NULLED AT PRF = -1dBm
PRF = -40dBm
PRF = +5dBm
TC = -40°C
LO LEAKAGE (dBm)
10
VBBI = VBBQ = 1.4VP-P
DIFFERENTIAL
3
OUTPUT POWER (dBm)
15
LO LEAKAGE vs. LO FREQUENCY
-40
MAX2021 toc20
INPUT SPLIT BETWEEN I AND Q,
fIF = 25MHz, fLO = 900MHz
OUTPUT POWER (dBm)
5
MAX2021 toc19
20
MAX2021 toc21
MODULATOR OUTPUT POWER
vs. INPUT POWER
LO LEAKAGE (dBm)
MAX2021
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
_______________________________________________________________________________________
10
15
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
DEMODULATOR
TC = +25°C
TC = +85°C
10
9
8
TC = -40°C
36
34
VCC = 5.0V
32
825
900
975
1050
1125
1200
TC = +25°C
38
TC = -40°C
36
34
32
TC = +85°C
30
750
825
900
975
1050
1125
1200
750
825
900
975
1050
1125
1200
DEMODULATOR INPUT IP2
vs. LO FREQUENCY
DEMODULATOR PHASE IMBALANCE
vs. LO FREQUENCY
DEMODULATOR AMPLITUDE IMBALANCE
vs. LO FREQUENCY
70
TC = +85°C
60
TC = -40°C
4
PLO = 0dBm
2
0
-2
PLO = -6dBm
-4
-6
-8
-10
825
900
975
1050
1125
1200
825
900
975
1050
1125
LO FREQUENCY (MHz)
LO PORT RETURN LOSS
vs. LO FREQUENCY
RF PORT RETURN LOSS
vs. LO FREQUENCY
PLO = 0dBm
+10
+15
PLO = -6dBm, -3dBm
+20
+10
+15
+20
+25
PLO = -6dBm, -3dBm, 0dBm, +3dBm
+30
+35
900
975
1050
LO FREQUENCY (MHz)
1125
1200
0
PLO = -6dBm, -3dBm, 0dBm, +3dBm
-0.05
-0.10
-0.15
750
825
900
975 1050 1125
LO FREQUENCY (MHz)
1200
-4
PLO = 0dBm
-5
fLO = 900MHz
-6
-7
-8
-9
fLO = 1000MHz
-10
-11
-12
+45
825
0.05
IF FLATNESS
vs. BASEBAND FREQUENCY
+40
+25
0.10
1200
MAX2021 toc33
+5
0
+5
RF PORT RETURN LOSS (dB)
MAX2021 toc32
PLO = +3dBm
0.15
-0.20
750
LO FREQUENCY (MHz)
0
0.20
MAX2021 toc31
PLO = -3dBm
6
IF OUTPUT POWER (dBm)
50
PLO = +3dBm
8
MAX2021 toc34
TC = +25°C
DEMODULATOR PHASE IMBALANCE (deg)
MAX2021 toc29
80
10
DEMODULATOR AMPLITUDE IMBALANCE (dB)
LO FREQUENCY (MHz)
MAX2021 toc30
LO FREQUENCY (MHz)
PLO = 0dBm, VCC = 5.0V
750
PLO = 0dBm, VCC = 5.0V
LO FREQUENCY (MHz)
90
750
MAX2021 toc28
VCC = 5.25V
30
750
DEMODULATOR INPUT IP2 (dBm)
38
40
VCC = 4.75V
7
LO PORT RETURN LOSS (dB)
PLO = 0dBm, TC = +25°C
DEMODULATOR INPUT IP3 (dBm)
11
40
DEMODULATOR INPUT IP3
vs. LO FREQUENCY
MAX2021 toc27
PLO = 0dBm, VCC = 5.0V
DEMODULATOR INPUT IP3 (dBm)
DEMODULATOR CONVERSION LOSS (dB)
12
DEMODULATOR INPUT IP3
vs. LO FREQUENCY
MAX2021 toc26
DEMODULATOR CONVERSION LOSS
vs. LO FREQUENCY
750
845
940
1035
LO FREQUENCY (MHz)
1130
1225
0
10
20
30
40
50
60
70
80
BASEBAND FREQUENCY (MHz)
_______________________________________________________________________________________
7
MAX2021
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.)
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
MAX2021
Pin Description
PIN
NAME
1, 5, 9–12, 14, 16–19, 22,
24, 27–30, 32, 34, 35, 36
GND
2
3
4
6
7
FUNCTION
Ground
RBIASLO3 3rd LO Amplifier Bias. Connect a 332Ω resistor to ground.
VCCLOA
LO
LO Input Buffer Amplifier Supply Voltage. Bypass to GND with 33pF and 0.1µF
capacitors as close to the pin as possible.
Local Oscillator Input. 50Ω input impedance.
RBIASLO1 1st LO Input Buffer Amplifier Bias. Connect a 432Ω resistor to ground.
N.C.
No Connection. Leave unconnected.
8
RBIASLO2 2nd LO Amplifier Bias. Connect a 619Ω resistor to ground.
13
VCCLOI1
I-Channel 1st LO Amplifier Supply Voltage. Bypass to GND with 33pF and 0.1µF
capacitors as close to the pin as possible.
15
VCCLOI2
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
25
BBQ-
RF Port
Baseband Quadrature Inverting Port
26
BBQ+
Baseband Quadrature Noninverting Port
31
VCCLOQ2
Q-Channel 2nd LO Amplifier Supply Voltage. Bypass to GND with 33pF and 0.1µF
capacitors as close to the pin as possible.
33
VCCLOQ1
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.
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 conjuction with the part’s precise in-phase and
quadrature channel matching, enable the device to possess excellent dynamic range, ACLR, 1dB compression
8
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
_______________________________________________________________________________________
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
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
4VP-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.
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
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
MAX2021
RF MODULATOR
50Ω
BBI
FREQ
50Ω
I/Q GAIN AND
OFFSET ADJUST
LO
0°
90°
∑
50Ω
BBQ
FREQ
50Ω
Figure 1. MAX5895 DAC Interfaced with MAX2021
_______________________________________________________________________________________________________
9
MAX2021
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.
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 89mVP-P differential
on the I and the Q inputs results in a -17dBm input
power level delivered to the I and Q internal 50Ω terminations. 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 comproC = 6.8pF
100Ω
I
MAX2021
RF-MODULATOR
L = 40nH
100Ω
C = 6.8pF
LO
0°
90°
∑
100Ω
Q
L = 40nH
100Ω
C = 6.8pF
Figure 2. Diplexer Network Recommended for GSM 900
Transmitter Applications
10
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 fLO
and 2fLO leakage, yet not affecting the flatness of the
baseband response at the highest baseband frequency.
The common-mode fLO and 2fLO signals 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 2fLO and fLO leakage, while the inductor provides high impedance at fLO and 2fLO to 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,
______________________________________________________________________________________
MAX2021
MAX2021
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
LO FREQ
(MHz)
800
900
1000
RF FREQ
(MHz)
801.8
901.8
1001.8
R1
Ω)
(Ω
R2
Ω)
(Ω
R3
Ω)
(Ω
ICC
(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
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
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
650
1000
550
173
14.6
-33.9
36.8
32.8
Note: VCC = 5V, PLO = 0dBm, TA = +25°C, I/Q voltage levels = 1.4VP-P differential.
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.
______________________________________________________________________________________
11
MAX2021
Table 1. Typical Performance Trade-Offs as a Function of Current Draw—Modulator Mode
MAX2021
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
Table 2. Typical Performance Trade-Offs as a Function of Current Draw—Demodulator Mode
LO FREQ
(MHz)
800
900
1000
RF FREQ
(MHz)
771
871
971
R1
Ω)
(Ω
R2
Ω)
(Ω
R3
Ω)
(Ω
ICC
(mA)
CONVERSION
LOSS (dB)
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
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
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
650
1000
550
173
9.61
31.5
76
Note: Used on PC board 180° combiners and off PC board quadrature combiner with VCC = 5V, PRF = -3dBm, PLO = 0dBm, TA = +25°C,
IF1 = 28MHz, IF2 = 29MHz.
12
______________________________________________________________________________________
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
GND
GND
GND
VCCLOQ1
GND
VCCLOQ2
GND
GND
GND
35
34
33
32
31
30
29
28
1
RBIASLO1
6
N.C.
7
RBIASLO2
8
GND
9
Σ
BIAS
LO1
BIAS
LO2
10
11
12
13
14
15
16
17
18
GND
5
0°
GND
GND
90°
GND
4
VCCLOI2
LO
GND
3
VCCLOI1
VCCLOA
GND
2
GND
RBIASLO3
MAX2021
BIAS
LO3
GND
GND
36
27
GND
26
BBQ+
25
BBQ-
24
GND
23
RF
22
GND
21
BBI-
20
BBI+
19
GND
THIN QFN
______________________________________________________________________________________
13
MAX2021
Pin Configuration/Functional Diagram
High-Dynamic-Range, Direct Up-/Downconversion
750MHz to 1200MHz Quadrature Mod/Demod
C12
0.1µF
36
RBIASLO3
VCC
C1
33pF
VCCLOA
C3
82pF
LO
GND
RBIASLO1
R1
432Ω
N.C.
RBIASLO2
R2
619Ω
GND
33
VCCLOQ2
GND
34
35
GND
32
1
GND
28
29
27
MAX2021
BIAS
LO3
2
GND
GND
30
31
26
3
25
90°
4
24
0°
5
6
Σ
22
7
21
BIAS
LO2
8
20
9
19
10
GND
VCC
GND
BBQ+
BBQGND
Q+
QC9
8.2pF
RF
23 RF
BIAS
LO1
C5
0.1µF
11
GND
12
GND
13
14
GND
C6
33pF
15
VCCLOI2
GND
C2
0.1µF
GND
GND
R3
332Ω
C11
0.1µF
VCC
C10
33pF
C13
33pF
VCCLOQ1
VCC
VCCLOI1
MAX2021
Typical Application Circuit
16
GND
17
GND
C7
33pF
GND
BBIBBI+
II+
GND
18
GND
C8
0.1µF
VCC
Table 3. Component List Referring to the Typical Application Circuit
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)
Chip Information
Package Information
For the latest package outline information, go to
www.maxim-ic.com/packages.
PROCESS: SiGe BiCMOS
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.
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is a registered trademark of Maxim Integrated Products, Inc.