1.7ghz to 2.5ghz, direct i/q modulator with vga and pa driver · cdma and wireless local-loop (wll)...
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General DescriptionThe MAX2720/MAX2721 are low-cost, high-performance,direct I/Q modulators designed for use in wideband-CDMA and wireless local-loop (WLL) systems. Theirdirect-upconversion architecture reduces system cost,component count, and board space compared todevices with dual-conversion architectures.
The MAX2720/MAX2721 include an I/Q modulator, avariable gain amplifier (VGA), and a power amplifier(PA) driver. The quadrature modulator accepts differentialbaseband I/Q signals and directly modulates an RFcarrier in the 1.7GHz to 2.1GHz range (MAX2720) orthe 2.1GHz to 2.5GHz range (MAX2721). The VGA pro-vides 35dB of output power control. The modulator’samplitude and phase balance yield 35dBc of sidebandsuppression and 30dBc of carrier suppression. Thesedevices feature an LO frequency doubler that allowsthe external LO source to operate at half-frequency orfull-frequency when disabled.
The MAX2720/MAX2721 operate from a single +2.7V to+3.3V supply and require only 77mA (MAX2720) or86mA (MAX2721) of supply current. An additional20mA of supply current is saved by disabling thestand-alone PA driver. A low-power shutdown modefurther reduces supply current to less than 0.1µA. Thedevice is packaged in the small 20-pin TSSOP-EP withexposed paddle to improve RF performance.
ApplicationsWireless Local Loop (WLL)
Wideband CDMA Systems
LMDS/MMDS
2.4GHz Broadband ISM Radios
DCS/PCS Base Stations
Features RF Frequency Range
1.7GHz to 2.1GHz (MAX2720)2.1GHz to 2.5GHz (MAX2721)
Integrated I/Q Modulator, LO Doubler, VGA, andPA Driver
35dB VGA Gain Control Range
35dBc Sideband Suppression
30dBc Carrier Suppression
Low Supply Current77mA (MAX2720), 86mA (MAX2721)20mA Reduction with PA Driver Disabled
0.1µA Supply Current in Shutdown Mode
+2.7V to +3.3V Single-Supply Operation
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1.7GHz to 2.5GHz, Direct I/Q Modulator withVGA and PA Driver
________________________________________________________________ Maxim Integrated Products 1
4
5
20 DRIN
19 GND
18 PC
VCC
2DROUT
1GND
17 MODOUT
16
15 VCC
14 Q-7I-
6VCC
GND
13 Q+
12 VCC
11 LO
9VCC
8I+
MAX2720/MAX2721
3SHDN
ENX2
0°90°
PA DRIVER
VGA
LO DOUBLER
LO P
HASE
SHI
FTER
10GND
Σ
x2BIAS
Functional Diagram
19-1606; Rev 0; 1/00
PART
MAX2720EUP
MAX2721EUP -40°C to +85°C
-40°C to +85°C
TEMP. RANGE PIN-PACKAGE
20 TSSOP-EP*
20 TSSOP-EP*
Pin Configuration appears at end of data sheet.
*Exposed paddle.
Ordering Information
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.For small orders, phone 1-800-835-8769.
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1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
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ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS(VCC = +2.7V to +3.3V; SHDN = VCC; ENX2 = GND; VPC = 0.5V; no input AC signals applied to I+, I-, Q+, Q-, LO, DRIN. MODOUTand DROUT = VCC, TA = -40°C to +85°C. Typical values are at VCC. = +3V, TA = +25°C, unless otherwise noted.)
AC ELECTRICAL CHARACTERISTICS(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
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.
VCC to GND..............................................................-0.3V to +6VENX2, SHDN, PC, I+, I-, Q+, Q-, LO,
DRIN to GND........................................-0.3V to (VCC + 0.3V)ENX2, SHDN Continuous Current.....................................±10mAPC Continuous Current.....................................................±10mAI+ to I-, Q+ to Q- ....................................................................±2VMODOUT, DROUT to GND Short-Circuit Duration .................10s
Continuous Power Dissipation (TA = +70°C)20-Pin TSSOP-EP (derate 21.7mW/°C above +70°C) ......1.74W
Operating Temperature Range ...........................-40°C to +85°CJunction Temperature ......................................................+150°CStorage Temperature Range ............................ -65°C to +150°CLead Temperature (soldering 10s) ................................. +300°C
MAX2721
MAX2720
0.5V < VPC < 2.5V, SHDN = GND
0.5V < VPC < 2.5V
MAX2720, DRIN = GND
MAX2721, DRIN = GND
SHDN = GND
CONDITIONS
86 129mA
77 119
V2.7 3.3Supply Voltage
Supply Current
2.5µA
-5 5PC Input Bias Current
µA-1 1Logic Input Bias Current
V0.5Logic Input Low Voltage
mA59 86Supply Current with PA Driver
Disabled 67 96
µA0.1 10Shutdown Supply CurrentV2.0Logic Input High Voltage
UNITSMIN TYP MAXPARAMETER
100kHz < fI = fQ < 2MHz
100kHz < fI+ = fQ+ < 2MHz
fI = fQ < BW-1dB
fI = fQ < BW-1dB
fI = fQ < BW-3dB, 0.5V < VPC < 2.5V
fI = fQ < BW-3dB, 0.5V < VPC < 2.5V
fI = fQ < BW-1dB
CONDITIONS
MHz40I/Q Input -3dB Bandwidth (Note 2)
MHz14 20
I/Q BASEBAND INPUTS
I/Q Input -1dB Bandwidth (Note 2)
ns1Group Delay Mismatch
ns1Group Delay Ripple
pF5I/Q Input Capacitance
Ω18I/Q Input Resistance Mismatch
mVp-p200 630I/Q Differential Input Level
dB±0.2I/Q Gain Imbalance
degrees±1.0I/Q Phase Imbalance
kΩ1.6 2.0I/Q Input Resistance
UNITSMIN TYP MAXPARAMETER
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1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
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AC ELECTRICAL CHARACTERISTICS (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
VPC = 2.5V
MAX2721
ENX2 = GND
MAX2721
MAX2720
ENX2 = VCC
VPC = 2.5V
0.5V < VPC < 2.5V
VPC = 2.5V, I/Q terminated in 50Ω
Slope between VPC = 1V and VPC = 2V
dBm+8 +14
MAX2721, VPC = 2.5V, ENX2 = VCC or GND, TA = +25°C (Note 3)
Output Third-Order Intercept Point(Note 4)
MAX2720
CONDITIONS
+3 +6
MAX2721
MAX2721
ENX2 = GND
30 40
ENX2 = VCC
20 25
ENX2 = GND
ENX2 = VCC
24 31
ENX2 = GND
ENX2 = VCC
MAX2720, 0.5V < VPC < 2.5V
+9 +14
2:1Output VSWR
dBm/Hz-141 -137Out-of-Band Noise Density
26 33
MAX2720
MAX2721
VCC = +3.0V + 100mVp-p at 10kHz/300kHz
MAX2720
0.5V < VPC < 2.5V
50 45MODOUT to LO Input Isolation
1.8:1
1.9:1
LO Input VSWR
2100 2500
MAX2720, VPC = 2.5V, ENX2 = VCC or GND, TA = +25°C (Note 3)
MHz1700 2100
2100 2500
1050 1250
1.8:1
Frequency Range (Note 3)
dBm+1 +5
Output 1dB Compression Point
dB/V19 23
dBc
PC Slope
VPC = 2.5V
41
VPC = 0.5V
Power-Supply Ripple Rejection(Note 5)
dBm
-12.5 -8.5 -6.0
Output Power, High
MAX2720
-10.5 -5.0 -2.5
MAX2721
MHz
UNITSMIN TYP MAX
850 1050
PARAMETER
LO Frequency Range (Note 3)1700 2100
28 35
1.6:1
MODULATOR OUTPUT
dBcCarrier Suppression
Sideband Suppression dBc
dB
VPC = 2.5V, TA = -40°C to +85°C
dB±1.0 ±1.8Output Power Variation Over
Temperature ±0.8 ±1.5
MAX2720
MAX2721
MAX2720
MAX2721
dBm-16 -10LO Input Power (Note 3)
VPC = 0.5V, ENX2 = VCC or GND
dB29 35
Power Control Range28 32
MAX2720
MAX2721
LO BUFFER, LO FREQUENCY DOUBLER, QUADRATURE GENERATOR
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1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
4 _______________________________________________________________________________________
Note 1: Min/max limits are guaranteed by design and characterization and are not production tested.Note 2: I/Q input bandwith is determined by the baseband source impedance and the I/Q input capacitance. The bandwith can be
increased by lowering the baseband source impedance.Note 3: MODOUT output power specifications are met over this frequency range for VPC = 2.5V and TA = +25°C.Note 4 IP3 measured with two tones, f1 = 500kHz and f2 = 600kHz, at 100mVp-p each.Note 5: Measured relative to desired upconverted signal level.Note 6 DROUT gain specifications are met over this frequency range at TA = +25°C.Note 7: IP3 measured with two tones, f1 = 1900MHz and f2 = 1901MHz, at -18dBm each.Note 8: IP3 measured with two tones, f1 = 2315MHz and f2 = 2316MHz, at -18dBm each.
CONDITIONS
MAX2720
MAX2721
MAX2720
MAX2721
UNITSMIN TYP MAXPARAMETER
MAX2720
MAX2720
MAX2721
MAX2720
MAX2721
TA = -40°C to +85°C
MHz1700 2100
Frequency Range (Note 6)
dBm+9.5 +12.5
Output 1dB Compression Point
2.6dB
2.4Noise Figure
±0.3 ±0.8
2100 2500
dB
11 13.5 15.5
Gain Variation Over Temperature
8.5 11.5 15.5
±0.4 ±0.8
MAX2721 (Note 8)
MAX2720 (Note 7)
MAX2721
dB19Reverse Isolation
+20 +24
dB65DROUT to LO Input Isolation
1.5:1Input VSWR
1.5:1Output VSWR
dBm+22 +24
Output Third-Order Intercept Point
+8 +11
AC ELECTRICAL CHARACTERISTICS (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
Gain (Note 6) dB
PA DRIVER
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1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
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0
30
20
10
40
50
60
70
80
90
100
2.7 2.92.8 3.0 3.1 3.2 3.3
SUPPLY CURRENT vs. SUPPLY VOLTAGEWITH PA DRIVER ENABLED
MAX
2720
/21t
oc01
SUPPLY VOLTAGE (V)
SUPP
LY C
URRE
NT (m
A)
TA = +85°C
TA = +25°C
TA = -40°C
ENX2 = GNDENX2 = VCC 0
30
20
10
40
50
60
70
80
90
100
2.7 2.92.8 3.0 3.1 3.2 3.3
SUPPLY CURRENT vs. SUPPLY VOLTAGEWITH PA DRIVER DISABLED
MAX
2720
/21t
oc02
SUPPLY VOLTAGE (V)
SUPP
LY C
URRE
NT (m
A)
ENX2 = GNDENX2 = VCC
DRIN = GNDTA = +85°C
TA = +25°C
TA = -40°C
-60
-50
-40
-30
-20
-10
0
1700 1800 1900 2000 2100
MODULATOR OUTPUT POWERvs. RF FREQUENCY
MAX
2720
/21t
oc04
RF FREQUENCY (MHz)
OUTP
UT P
OWER
(dBm
)
TA = +85°C
VPC = 2.5V
VPC = 1.5V
VPC = 0.5V
TA = +25°C
TA = -40°C
-60
-40
-50
-20
-30
-10
0
-19 -13 -11-17 -15 -9 -7 -5
MAX
2720
/21t
oc05
LO POWER (dBm)
OUTP
UT P
OWER
(dBm
) AND
CAR
RIER
AN
D SI
DEBA
ND S
UPPR
ESSI
ON (d
Bc) OUTPUT POWER
CARRIER SUPPRESSION
SIDEBAND SUPPRESSION
MODULATOR PERFORMANCE vs. LO POWER (ENX2 = GND)
-70
-50
-60
-20
-30
-40
-10
0
-19 -13 -11-17 -15 -9 -7 -5
MAX
2720
/21t
oc06
LO POWER (dBm)
OUTP
UT P
OWER
(dBm
) AND
CAR
RIER
AN
D SI
DEBA
ND S
UPPR
ESSI
ON (d
Bc) OUTPUT POWER
MODULATOR PERFORMANCE vs. LO POWER (ENX2 = VCC)
CARRIER SUPPRESSION
SIDEBANDSUPPRESSION
Typical Operating Characteristics(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2720
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1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
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-50
-35
-40
-45
-15
-10
-20
-30
-25
-5
0
0 1.50.5 1.0 2.0 2.5 3.0
MAX
2720
/21t
oc10
PC VOLTAGE (V)
OUTP
UT P
OWER
(dBm
)
MODULATOR OUTPUT POWER vs. PC VOLTAGE (ENX2 = VCC)
2.1GHz
1.9GHz
1.7GHz
-70
-50
-60
-40
-10
-20
-30
0
0 1.50.5 1.0 2.0 2.5 3.0
MAX
2720
/21t
oc11
PC VOLTAGE (V)
CARR
IER
SUPP
RESS
ION
(dBc
)
MODULATOR CARRIER SUPPRESSION vs. PC VOLTAGE (ENX2 = VCC)
2.1GHz
1.9GHz
1.7GHz
-50
-35
-40
-45
-15
-10
-20
-30
-25
-5
0
0 1.50.5 1.0 2.0 2.5 3.0
MAX
2720
/21t
oc12
PC VOLTAGE (V)
SIDE
BAND
SUP
PRES
SION
(dBc
)
MODULATOR SIDEBAND SUPPRESSION vs. PC VOLTAGE (ENX2 = VCC)
2.1GHz
1.7GHz1.9GHz
Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
-40
-35
-15
-10
-20
-30
-25
-5
0
0 1.50.5 1.0 2.0 2.5 3.0M
AX27
20/2
1toc
08
PC VOLTAGE (V)
CARR
IER
SUPP
RESS
ION
(dBc
)MODULATOR CARRIER SUPPRESSION
vs. PC VOLTAGE (ENX2 = GND)
2.1GHz
1.9GHz
1.7GHz-60
-40
-50
-20
-30
-10
0
0 1.0 1.50.5 2.0 2.5 3.0
MAX
2720
/21t
oc09
PC VOLTAGE (V)
SIDE
BAND
SUP
PRES
SION
(dBc
)
MODULATION SIDEBAND SUPPRESSIONvs. PC VOLTAGE (ENX2 = GND)
2.1GHz
1.9GHz
1.7GHz
MAX2720
-50
-35
-40
-45
-15
-10
-20
-30
-25
-5
0
0 1.50.5 1.0 2.0 2.5 3.0
MAX
2720
/21t
oc07
PC VOLTAGE (V)
OUTP
UT P
OWER
(dBm
)
1.9GHz
1.7GHz
2.1GHz
MODULATOR OUTPUT POWER vs. PC VOLTAGE (ENX2 = GND)
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Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
-35
-40
-15
-10
-20
-30
-25
-5
0
0 1.50.5 1.0 2.0 2.5 3.0
MAX
2720
/21t
oc14
PC VOLTAGE (V)
CARR
IER
SUPP
RESS
ION
(dBc
)
MODULATOR CARRIER SUPPRESSION vs. PC VOLTAGE (ENX2 = GND)
TA = +85°C
TA = +25°CTA = -40°C
-55
-60
-20
-30
-40
-10
0
0 1.50.5 1.0 2.0 2.5 3.0
MAX
2720
/21t
oc15
PC VOLTAGE (V)
SIDE
BAND
SUP
PRES
SION
(dBc
)
MODULATOR SIDEBAND SUPPRESSION vs. PC VOLTAGE (ENX2 = GND)
TA = +85°C
TA = +25°C
TA = -40°C
-45
-40
-50
-15
-20
-25
-35
-30
-5
-10
0
0 1.50.5 1.0 2.0 2.5 3.0
MAX
2720
/21t
oc16
PC VOLTAGE (V)
OUTP
UT P
OWER
(dBm
)
MODULATOR OUTPUT POWER vs. PC VOLTAGE (ENX2 = VCC)
TA = +85°C
TA = +25°C
TA = -40°C
-40
-70
-50
-60
-20
-30
-10
0
0 1.50.5 1.0 2.0 2.5 3.0
MAX
2720
/21t
oc17
PC VOLTAGE (V)
CARR
IER
SUPR
ESSI
ON (d
Bc)
MODULATOR CARRIER SUPPRESSION vs. PC VOLTAGE (ENX2 = VCC)
TA = +85°C
TA = +25°C
TA = -40°C
-40
-50
-60
-20
-30
-10
0
0 1.50.5 1.0 2.0 2.5 3.0
MAX
2720
/21t
oc18
PC VOLTAGE (V)
SIDE
BAND
SUP
RESS
ION
(dBc
)
TA = +85°C
TA = -40°C
MODULATOR SIDEBAND SUPPRESSION vs. PC VOLTAGE (ENX2 = VCC)
TA = +25°C
MAX2720
-50
-35
-40
-45
-15
-10
-20
-30
-25
-5
0
0 1.50.5 1.0 2.0 2.5 3.0
MAX
2720
/21t
oc13
PC VOLTAGE (V)
OUTP
UT P
OWER
(dBm
)
TA = +85°C
TA = +25°C
TA = -40°C
MODULATOR OUTPUT POWER vs. PC VOLTAGE (ENX2 = GND)
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-6010 10,0001000100
MODULATOR OUTPUT POWER vs. INPUT LEVEL (TA = +25°C)
10
-30
-40
-50
0
-10
-20
MAX
2720
toc2
0INPUT LEVEL (mVp-p)
OUTP
UT P
OWER
(dBm
)
VPC = 2.5V
VPC = 2.0V
VPC = 1.5V
VPC = 1.0V
VPC = 0.5V
-6010 10,0001000100
MODULATOR OUTPUT POWER vs. INPUT LEVEL (TA = +85°C)
10
-30
-40
-50
0
-10
-20
MAX
2720
toc2
1
INPUT LEVEL (mVp-p)
OUTP
UT P
OWER
(dBm
)
VPC = 2.5V
VPC = 2.0V
VPC = 1.5V
VPC = 1.0V
VPC = 0.5V
-20
-15
-30
-25
15
10
0
-5
-10
5
20
25
1.00 0.5 1.5 2.0 2.5 3.0
MODULATOR OUTPUT IP3 vs. PC VOLTAGE
MAX
2720
/21t
oc22
PC VOLTAGE (V)
OUTP
UT IP
3 (d
Bm) TA = +25°C
TA = -40°C
TA = +85°C
1.0
1.2
1.6
2.0
2.4
2.8
850 890 930 970 1010 1050
MAX
2720
-24
FREQUENCY (MHz)
VSW
R
LO PORT VSWR vs. LO FREQUENCY (ENX2 = GND)
1.0
1.4
1.8
2.0
2.4
2.8
1700 1780 1860 1940 2020 2100
MAX
2720
-25
FREQUENCY (MHz)
VSW
R
LO PORT VSWR vs. LO FREQUENCY (ENX2 = VCC)
Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2720
-6010 10,0001000100
MODULATOR OUTPUT POWER vs. INPUT LEVEL (TA = -40°C)
10
-30
-40
-50
0
-10
-20
MAX
2720
toc1
9
INPUT LEVEL (mVp-p)
OUTP
UT P
OWER
(dBm
)
VPC = 2.5V
VPC = 2.0V
VPC = 1.5V
VPC = 1.0V
VPC = 0.5V
MA
X2
72
0/M
AX
27
21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
_______________________________________________________________________________________ 9
10
11
12
13
14
15
2.7 2.92.8 3.0 3.1 3.2 3.3
PA DRIVER GAIN vs. SUPPLY VOLTAGE
MAX
2720
/21t
oc27
SUPPLY VOLTAGE (V)
GAIN
(dB)
TA = +85°CTA = +25°C
TA = -40°C
20
22
21
23
24
26
25
28
27
29
30
2.7 2.92.8 3.0 3.1 3.2 3.3
PA DRIVER OUTPUT IP3 vs. SUPPLY VOLTAGE
MAX
2720
/21t
oc28
SUPPLY VOLTAGE (V)
OUTP
UT IP
3 (d
Bm) TA = +85°C
TA = +25°C
TA = -40°C
Page 1
10
12
11
13
14
16
15
18
17
19
20
2.7 2.92.8 3.0 3.1 3.2 3.3
PA DRIVER OUTPUT P1dB vs. SUPPLY VOLTAGE
MAX
2720
/21t
oc29
SUPPLY VOLTAGE (V)
OUTP
UT P
1dB
(dBm
)
TA = +85°C
TA = +25°C
TA = -40°C
0
4
2
6
8
12
10
16
14
18
20
1700 1800 1900 2000 2100
PA DRIVER GAIN vs. RF FREQUENCY
MAX
2720
/21t
oc30
RF FREQUENCY (MHz)
GAIN
(dB)
TA = +25°CTA = +85°C
TA = -40°C
Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
20
22
21
23
24
26
25
28
27
29
30
1700 1800 1900 2000 2100
PA DRIVER OUTPUT IP3 vs. FREQUENCY
MAX
2720
/21t
oc31
FREQUENCY (MHz)
OUTP
UT IP
3 (d
Bm)
TA = +25°CTA = +85°C
TA = -40°C
10
12
11
13
14
16
15
18
17
19
20
1700 1800 1900 2000 2100
PA DRIVER OUTPUT P1dB COMPRESSION POINT vs. FREQUENCY
MAX
2720
/21t
oc32
FREQUENCY (MHz)
OUTP
UT P
1dB
(dBm
)
TA = +25°C
TA = -40°C
TA = +85°C
MAX2720
MA
X2
72
0/M
AX
27
21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
10 ______________________________________________________________________________________
Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
0
1.0
0.5
1.5
2.0
3.0
2.5
4.0
3.5
4.5
5.0
1700 1800 1900 2000 2100
PA DRIVER NOISE FIGURE vs. FREQUENCY
MAX
2720
/21t
oc33
FREQUENCY (MHz)
NOIS
E FI
GURE
(dB)
TA = +25°CTA = +85°C
TA = -40°C-15
-10
-5
10
5
0
15
20
-25 -15 -10-20 -5 50 10 2015
PA DRIVER OUTPUT POWER vs. INPUT POWER
MAX
2720
/21t
oc34
INPUT POWER (dBm)
OUTP
UT P
OWER
(dBm
)
TA = -40°C
TA = +85°C
TA = +25°C
MAX2720
MA
X2
72
0/M
AX
27
21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
______________________________________________________________________________________ 11
-50
-40
-45
-30
-35
-20
-25
-15
-5
-10
0
2100 2200 2300 2400 2500
MODULATOR OUTPUT POWERvs. RF FREQUENCY
MAX
2720
toc3
8
RF FREQUENCY (MHz)
OUTP
UT P
OWER
(dBm
)
VPC = 2.5V
VPC = 1.5V
VPC = 0.5V
TA= +85°CTA= +25°C
TA= -40°C
-40
-30
-35
-25
-20
-5
-15
-10
0
-19 -17 -15 -13 -11 -9 -7 -5
MODULATOR PERFORMANCE vs. LO POWER (ENX2 = GND)
MAX
2720
/21t
oc39
RF FREQUENCY (MHz)
OUTP
UT P
OWER
(dBm
) AND
CAR
RIER
AND
SI
DEBA
ND S
UPPR
ESSI
ON (d
Bc)
OUTPUT POWER
CARRIER SUPPRESSION
SIDEBAND SUPPRESSION
-40
-30
-35
-25
-20
-15
-5
-10
0
-19 -17 -15 -13 -9 -7-11 -5
MODULATOR PERFORMANCE vs. LO POWER (ENX2 = VCC)
MAX
2720
/21t
oc40
LO POWER (dBm)
OUTP
UT P
OWER
(dBm
) AND
CAR
RIER
AND
SI
DEBA
ND S
UPPR
ESSI
ON (d
Bc)
OUTPUT POWER
CARRIER SUPPRESSION
SIDEBAND SUPPRESSION
20
30
50
40
70
60
110
100
90
80
120
2.7 2.92.8 3.0 3.1 3.2 3.3
SUPPLY CURRENT vs. SUPPLY VOLTAGEWITH PA DRIVER ENABLED
MAX
2720
/21t
oc35
SUPPLY VOLTAGE (V)
SUPP
LY C
URRE
NT (m
A)
TA = +85°C
TA = +25°C
TA = -40°C
ENX2 = GNDENX2 = VCC
20
40
30
60
50
100
90
80
70
120
110
2.7 2.92.8 3.0 3.1 3.2 3.3
SUPPLY CURRENT vs. SUPPLY VOLTAGEWITH PA DRIVER DISABLED
MAX
2720
/21t
oc36
SUPPLY VOLTAGE (V)
SUPP
LY C
URRE
NT (m
A)
TA = +25°C
TA = -40°C
TA = +85°C
DRIN = GND
ENX2 = GNDENX2 = VCC
Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2721
MA
X2
72
0/M
AX
27
21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
12 ______________________________________________________________________________________
Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
-40
-35
-30
-25
-20
-15
-10
-5
0
0 1.00.5 1.5 2.0 2.5 3.0
MODULATOR SIDEBAND SUPRESSION vs. PC VOLTAGE (ENX2 = VCC)
MAX
2721
TOC
46
PC VOLTAGE (V)
SIDE
BAND
SUP
RESS
ION
(dBc
)
2.1GHz
2.5GHz2.3GHz
-45
-35
-40
-20
-25
-30
-5
-10
-15
0
0 1.00.5 1.5 2.0 2.5 3.0
MODULATOR OUTPUT POWERvs. PC VOLTAGE (ENX2 = VCC)
MAX
2721
TOC
44
PC VOLTAGE (V)
OUTP
UT P
OWER
(dBm
)
2.1GHz
2.3GHz2.5GHz
-45
-35
-40
-20
-25
-30
-5
-10
-15
0
0 1.00.5 1.5 2.0 2.5 3.0
MODULATOR CARRIER SUPRESSIONvs. PC VOLTAGE (ENX2 = VCC)
MAX
2721
TOC
45
PC VOLTAGE (V)
CARR
IER
SUPR
ESSI
ON (d
Bc)
2.1GHz
2.3GHz 2.5GHz
-40
-30
-35
-25
-20
-15
-5
-10
0
0 0.5 1.0 2.0 2.51.5 3.0
MAX
2720
/21t
oc42
PC VOLTAGE (V)
CARR
IER
SUPP
RESS
ION
(dBm
)
CARRIER SUPPRESSION vs. PC VOLTAGE(ENX2 = GND)
2.5GHz
2.1GHz
2.3GHz
-40
-35
-30
-25
-20
-15
-10
-5
0
0 1.00.5 1.5 2.0 2.5 3.0
SIDEBAND SUPRESSION vs. PC VOLTAGE(ENX2 = GND)
MAX
2721
TOC
43
PC VOLTAGE (V)
SIDE
BAND
SUP
RESS
ION
(dBc
)
2.3GHz2.1GHz
2.5GHz
MAX2721
-40
-30
-35
-25
-20
-15
-5
-10
0
0 0.5 1.0 1.5 2.0 3.02.5
MAX
2720
/21t
oc41
PC VOLTAGE (V)
OUTP
UT P
OWER
(dBm
)
MODULATOR OUTPUT POWER vs. PC VOLTAGE (ENX2 = GND)
2.3GHz
2.1GHz
2.5GHz
MA
X2
72
0/M
AX
27
21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
______________________________________________________________________________________ 13
Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
-40
-35
-30
-25
-20
-15
-10
-5
0
0 1.00.5 1.5 2.0 2.5 3.0
MODULATOR OUTPUT POWERvs. PC VOLTAGE (ENX2 = GND)
MAX
2721
TOC
47
PC VOLTAGE (V)
OUTP
UT P
OWER
(dBm
)
TA = +25°C
TA = -40°C
TA = +85°C
-35
-25
-30
-15
-20
-5
-10
0
0 1.0 1.50.5 2.0 2.5 3.0
MODULATOR CARRIER SUPRESSION vs. PC VOLTAGE (ENX2 = GND)
MAX
2721
TOC
48PC VOLTAGE (V)
CARR
IER
SUPR
ESSI
ON (d
Bc)
TA = +85°C
TA = +25°C
TA = -40°C
-40
-35
-30
-25
-20
-15
-10
-5
0
0 1.00.5 1.5 2.0 2.5 3.0
MODULATOR SIDEBAND SUPRESSIONvs. PC VOLTAGE (ENX2 = GND)
MAX
2721
TOC
49
PC VOLTAGE (V)
SIDE
BAND
SUP
RESS
ION
(dBc
)
TA = -40°CTA = +25°C
TA = +85°C
-40
-35
-30
-25
-20
-15
-10
-5
0
0 1.00.5 1.5 2.0 2.5 3.0
MODULATOR OUTPUT POWER vs. PC VOLTAGE (ENX2 = VCC)
MAX
2721
TOC
450
PC VOLTAGE (V)
OUTP
UT P
OWER
(dBm
)
TA = -40°C
TA = +85°C
TA = +25°C
-40
-35
-30
-25
-20
-15
-10
-5
0
0 1.00.5 1.5 2.0 2.5 3.0
MODULATOR CARRIER SUPRESSIONvs. PC VOLTAGE (ENX2) = VCC
MAX
2721
TOC
51
PC VOLTAGE (V)
CARR
IER
SUPP
RESS
ION
(dBc
)
TA = -40°C
TA = +25°C
TA = +85°C
-40
-35
-30
-25
-20
-15
-10
-5
0
0 1.00.5 1.5 2.0 2.5 3.0
MODULATOR SIDEBAND SUPPRESSIONvs. PC VOLTAGE (ENX2 = VCC)
MAX
2721
TOC
52
PC VOLTAGE (V)
SIDE
BAND
SUP
PRES
SION
(dBc
)
TA = -40°C
TA = +85°C
TA = +25°C
MAX2721
MA
X2
72
0/M
AX
27
21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
14 ______________________________________________________________________________________
-60
-50
-40
-30
-20
-10
0
10
20
10 1000100 10,000
MODULATOR OUTPUT POWERvs. INPUT LEVEL (TA = +85°C)
MAX
2721
TOC
55
INPUT LEVEL (mVp-p)
OUTP
UT P
OWER
(dBm
)
VPC = 2.5V
VPC = 1.5V
VPC = 2.0V
VPC = 1.0V
VPC = 0.5V
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
0 0.5 1.0 1.5 2.0 2.5 3.0
MODULATOR OUTPUT IP3 vs. PC VOLTAGE
MAX
2721
TOC
56
INPUT LEVEL (mVp-p)
OUTP
UT IP
3 (d
Bm)
TA = -40°C
TA = +85°C
TA = +25°C
-20
-15
-10
-25
15
10
-5
0
5
20
25
1.50.5 1.0 2.0 2.5
MODULATOR OUTPUT P1dB COMPRESSION POINT vs. PC VOLTAGE
MAX
2720
/21t
oc57
PC VOLTAGE (V)
OUTP
UT P
1dB
(dBm
)
TA = +85°C
TA = +25°C
TA = -40°C
1.0
1.4
1.8
2.0
2.4
2.6
MAX
2721
toc5
8
2100 2180 2260 2340 2420 2500
LO PORT VSWR vs. LO FREQUENCY(ENX2 = VCC)
FREQUENCY (MHz)
VSW
R
-60
-50
-40
-30
-20
-10
0
10
20
10 1000100 10,000
MODULATOR OUTPUT POWERvs. INPUT LEVEL (TA = +25°C)
MAX
2721
TOC
54INPUT LEVEL (mVp-p)
OUTP
UT P
OWER
(dBm
)
VPC = 2.5V
VPC = 1.5V
VPC = 2.0V
VPC = 1.0V
VPC = 0.5V
Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2721
-60
-50
-40
-30
-20
-10
0
10
20
10 1000100 10,000
MODULATOR OUTPUT POWERvs. INPUT LEVEL (TA = -40°C)
MAX
2721
TOC
53
INPUT LEVEL (mVp-p)
OUTP
UT P
OWER
(dBm
)
VPC = 2.5V
VPC = 1.5V
VPC = 2.0V
VPC = 1.0V
VPC = 0.5V
MA
X2
72
0/M
AX
27
21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
______________________________________________________________________________________ 15
8
10
9
11
12
14
13
16
15
17
18
2.7 2.92.8 3.0 3.1 3.2 3.3
PA DRIVER OUTPUT P1dB vs. SUPPLY VOLTAGE
MAX
2720
/21t
oc63
SUPPLY VOLTAGE (V)
OUTP
UT P
1dB
(dBm
)
TA = +85°C
TA = +25°C
TA = -40°C
1.0
1.4
1.6
1.8
2.0
MAX
2721
toc5
9
LO PORT VSWR vs. FREQUENCY(ENX2 = GND)
1050 1090 1130 1170
FREQUENCY (MHz)
1210 1250
VSW
R
10
11
13
12
14
15
2.7 2.92.8 3.0 3.1 3.2 3.3
PA DRIVER GAIN vs. SUPPLY VOLTAGE
MAX
2721
TOC
61SUPPLY VOLTAGE (V)
GAIN
(dB)
TA = +25°CTA = -40°C
TA = +85°C
-2
2
0
4
6
10
8
14
12
16
18
2100 2200 2300 2400 2500
PA DRIVER GAIN vs. RF FREQUENCY
MAX
2720
/21t
oc64
RF FREQUENCY (MHz)
GAIN
(dB)
TA = +25°CTA = +85°C
TA = -40°C
20
22
21
23
24
26
25
28
27
29
30
2.7 2.92.8 3.0 3.1 3.2 3.3
PA DRIVER OUTPUT IP3 vs. SUPPLY VOLTAGE
MAX
2720
/21t
oc62
SUPPLY VOLTAGE (V)
OUTP
UT IP
3 (d
Bm) TA = +85°C
TA = -40°C
TA = +25°C
Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
20
22
21
23
24
26
25
28
27
29
2100 2200 2300 2400 2500
PA DRIVER OUTPUT IP3 vs. FREQUENCY
MAX
2720
/21t
oc65
FREQUENCY (MHz)
OUTP
UT IP
3 (d
Bm) TA = +85°C
TA = +25°C
TA = -40°C
MAX2721
MA
X2
72
0/M
AX
27
21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
16 ______________________________________________________________________________________
0
2
1
3
4
6
5
8
7
9
10
2100 2200 2300 2400 2500
PA DRIVER NOISE FIGURE vs. FREQUENCY
MAX
2720
/21t
oc67
FREQUENCY (MHz)
NOIS
E FI
GURE
(dB)
TA = +25°C
TA = -40°CTA = +85°C
-15
-10
5
10
15
2.0
-25 -15 -10-20 -5 -50 10 2015
PA DRIVER OUTPUT POWER vs. INPUT POWER
MAX
2720
/21t
oc68
INPUT POWER (dBm)
OUTP
UT P
OWER
(dBm
)
TA = -40°C
TA = +85°C
TA = +25°C
Typical Operating Characteristics (continued)(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a1kΩ source impedance, single-ended, fI+ = fQ+ = 500kHz, VI+ = VQ+ = 200mVp-p, PLO = -13dBm, fLO = 950MHz (MAX2720), fLO =1157.5MHz (MAX2721), PDRIN = -12dBm, fDRIN = 1900MHz (MAX2720), fDRIN = 2315MHz (MAX2721), MODOUT and DROUT portsare matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2721
0
4
2
6
8
12
10
16
14
18
20
2100 2200 2300 2400 2500
PA DRIVER OUTPUT P1dBvs. FREQUENCY
MAX
2720
/21t
oc66
FREQUENCY (MHz)
OUTP
UT P
1dB
(dBm
)
TA = +25°C
TA = +85°C
TA = -40°C
MA
X2
72
0/M
AX
27
21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
______________________________________________________________________________________ 17
Detailed DescriptionThe MAX2720/MAX2721 upconvert in-phase (I) andquadrature (Q) baseband signals directly to RFfrequencies of 1700MHz to 2100MHz (MAX2720) or2100MHz to 2500MHz (MAX2721). They are designedfor wideband-CDMA and WLL systems where direct I/Qmodulation of the RF carrier reduces system cost, com-ponent count, and board space compared todual-conversion architectures.
Internally, the MAX2720/MAX2721 include an I/Q mod-ulator, a variable gain amplifier (VGA), and a PA driver.Separate modulator output and PA driver input portsallow insertion of a bandpass filter between the modulatorand PA driver for increased noise rejection. Disable thestand-alone PA driver to reduce current consumption.A low-power shutdown mode further reduces currentconsumption to less than 0.1µA. Additionally, a logic-level control disables or enables an internal frequencydoubler that allows the external LO to run at full or halffrequency.
NAME FUNCTION
1, 5, 10, 19, EP GNDGround. Connect to ground plane with lowest inductance path. Solder exposed paddleevenly to the board ground plane.
2 DROUTPA Driver Open-Collector Output Port. Requires an external matching network and a pull-up inductor to VCC for proper biasing. See Typical Application Circuit for recommendedcomponent values.
PIN
3 SHDNShutdown Control Input. Drive with a logic-level high to enable the device. Drive with a logic-level low to disable the device. Bypass with a 1000pF capacitor to ground, as close to thepin as possible to minimize the amount of external noise coupled onto the control line.
4, 6, 9, 12, 15 VCCSupply Voltage Input. Bypass to ground with the specified capacitor as close to the pin aspossible. (See Typical Application Circuit.)
16 ENX2
Logic-Level Enable Input for LO Doubler. Drive with a logic-level low to enable the doubler,allowing the external LO to run at half-frequency, fLO = fOUT / 2. Drive with a logic-levelhigh to disable the doubler, and allow the external LO to run at full-frequency, fLO = fOUT.Bypass with a 1000pF capacitor to ground as close to the pin as possible to minimizenoise coupled into the control line.
13, 14 Q+, Q-Quadrature Differential Input Ports. Requires DC-blocking capacitors. See Typical ApplicationCircuit for recommended component values.
11 LOLocal Oscillator input. Internally matched to 50Ω over the operating frequency band.Requires a DC-blocking capacitor. See Typical Application Circuit for recommended com-ponent values.
7, 8 I-, I+In-Phase Differential Input Ports. Requires DC-blocking capacitors. See Typical ApplicationCircuit for recommended component values.
20 DRIN
PA Driver Amplifier Input Port. Requires an external matching network and a DC-blockingcapacitor that can be part of the matching network. See Typical Application Circuit for rec-ommended component values. Connect to ground to disable the PA Driver and reducesupply current.
18 PCModulator Power Control Input. Apply a voltage between 0.5V to 2.5V to vary the outputpower of the I/Q modulator over a 30dB range. Bypass with a 1000pF capacitor to groundas close to the pin as possible to minimize noise on the control line.
17 MODOUTModulator Open-Collector Output Port. Requires an external matching network and a pull-up inductor to VCC for proper biasing. See Typical Application Circuit for recommendedcomponent values.
Pin Description
MA
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0/M
AX
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1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
18 ______________________________________________________________________________________
I/Q ModulatorThe MAX2720/MAX2721 modulator is composed of a pairof matched double-balanced mixers, an active LO quad-rature generator, and a summing amplifier. The pair ofmixers accept differential I/Q baseband signals thatdirectly modulate the internal 0° and 90° LO signalsapplied to the I/Q mixers. An external LO source drivesan internal LO quadrature generator that shifts the phaseof the LO signal applied to the Q mixer by 90° relative tothe LO signal applied to the I channel mixer. The modu-lated output of the I/Q mixers is summed together, andthe undesired sideband is suppressed.
The I+, I-, Q+, and Q- input ports feature high-linearitybuffer amplifiers with a -1dB bandwidth of 20MHz anda -3dB bandwidth of 38MHz (1kΩ I/Q source imped-ance), and accept differential input voltages up to630mVp-p. Input bandwith can be extended to beyond100MHz by lowering the I/Q source impedance. Theports are internally biased and therefore require DC-blocking capacitors. For single-ended operation,bypass the I- and Q- ports with a capacitor to groundequal in value to the DC-blocking capacitors used onthe I+ and Q+ ports. See the Typical Application Circuitfor recommended component values.
Variable Gain Amplifier (VGA)A VGA follows the summing amplifier of the I/Q modulator.Apply a voltage between 0.5V and 2.5V to PC to varythe output power of the modulator over a 32dB span.
The open-collector MODOUT output requires a pull-upinductor to VCC for proper biasing, an external matchingnetwork for optimum power transfer, and a DC-blockingcapacitor. Since the MAX2720/MAX2721 are optimizedfor different frequency ranges, they require differentoutput matching networks. See the MAX2720 and
MAX2721 Typical Application Circuit for recommendedcomponent values. See Table 1 for matching to otherfrequencies.
LO Buffer and LO Frequency DoublerThe MAX2720/MAX2721 feature an internal LO frequencydoubler that allows the external LO source to run at full orhalf frequency (Table 2). Operating the LO at half fre-quency reduces injection-pulling of the voltage-con-trolled oscillator (VCO) from the PA, and reduces thecomplexity of designing a high-frequency VCO. Aninternal two-pole bandpass filter is integrated beforethe LO phase-shift network to help reduce LO harmoniccontent and spurious mixing.
To enable the LO frequency doubler, drive ENX2 to alogic-level low and operate the external LO source athalf the RF carrier frequency. To disable the LOfrequency doubler, drive ENX2 to a logic-level high andrun the external LO source at the RF carrier frequency.See Table 2 for LO input frequency ranges.
The LO port is a single-ended input that achieves aVSWR of better than 2:1 over the specified LO inputfrequency range. Since the port is internally terminatedwith 50Ω, it requires a DC-blocking capacitor. See theTypical Applications Circuits for recommended compo-nent values. For optimum performance, drive the LOport with an input power of -16dBm to -10dBm. Drivingthe LO port with lower input power levels may affectquadrature performance, while higher input powersmay increase LO leakage.
PA Driver AmplifierThe PA driver provides a gain of 13.5dB for theMAX2720 and 11.5dB for the MAX2721. The DRINinput port requires an external matching network and a
-71.0
-68.9
-93.80.8320.896
-91.3
-66.6
0.861
S22 PHASE(degrees)
0.9091750
1800
-77.1
75.4
-97.10.8660.878
-94.8
-74.6
0.834
-73.0
0.8681950
2000
-94.70.8070.871
-94.40.8110.8841850
1900
-86.50.8610.914
S22 PHASE(degrees)
S22 MAGS22 MAGFREQUENCY
(MHz)
1700
2200
2150
2100
FREQUENCY(MHz)
2400
2350
2300
2250
Table 1. VGA MODOUT S22 Parameters (VCC = 3.0V, VPC = 2.5V, TA = +25°C)
82.5
-79.6
-104.50.9050.897
-100.50.8910.8922050
2100 2500
2450
MAX2720 MAX2721
MA
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72
0/M
AX
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1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
______________________________________________________________________________________ 19
DC-blocking capacitor that can be part of the matchingnetwork. The DROUT open-collector output portrequires an external matching network and a pull-upinductor to VCC for proper biasing. The pull-up inductoris incorporated as part of the matching network. Seethe MAX2720 and MAX2721 Typical Application Circuitfor recommended component values. Refer to Table 3for matching to other frequencies.
If the additional gain of the PA driver is not required,disable the PA driver to reduce current consumption.To disable the PA driver, short pin 20 (DRIN) to groundand leave pin 2 unconnected.
ShutdownApply a logic-level high to the SHDN pin to enable theMAX2720/MAX2721. Apply a logic-level low voltage todisable the device and reduce supply current to lessthan 0.1µA.
Applications InformationLayout Considerations
A properly designed PC board is an essential part ofany RF circuit. A ground plane is essential. Keep RFsignal lines as short as possible to reduce losses, radi-ation, and inductance. Use separate, low-inductancevias to the ground plane for each pin. For best perfor-mance, solder the exposed pad on the bottom of thedevice package evenly to the board ground plane.Remove the ground plane under the external VCO andlowpass filters to reduce the effects of parasitic capaci-
tance. In direct I/Q modulator applications, radiatedpower from the PA can couple into the VCO tank. Toreduce PA injection-pulling, the external VCO should behoused in a separate shielded compartment if possible.
Power-Supply, Logic, and PCInput Bypassing
Proper voltage supply bypassing is essential for high-fre-quency circuit stability. With the exception of pin 6,bypass all VCC pins with a 470pF capacitor as close tothe VCC pins as possible. The decoupling capacitor forpin 6 also serves as part of an on-chip matching network,so it should be chosen to resonate out series inductanceon the board. Some empirical adjustment may yieldincreased output power. See the MAX2720/MAX2721Typical Application Circuit for suggested values.
Bypass the ENX2, SHDN, and PC inputs with a 1000pFcapacitor to ground to minimize noise injected into thedevice. Use a series resistor (10kΩ typ) to furtherreduce coupling of high-frequency signals into thedevice.
Voltage supply layout is also critical to achieve optimumperformance. The IC has several RF processing stagesthat use the various VCC pins, and while they haveon-chip decoupling, off-chip interaction between themmay degrade gain, linearity, carrier suppression, andoutput power control range. The supplies associatedwith pins 2, 6, 15 (MAX2721 only), and 17 lie directly inthe RF signal path. Pins 4, 12, and 15 carry LO signalcurrents, so it is important to keep them from interactingwith the RF signal path to prevent poor carrier suppres-sion. The VGA generates discarded signal currents onpin 4, which also need to be kept away from the signalpath supplies. Because there is a great deal of gain following from the first RF stage, it is also important toprevent coupling from pins 2, 4, 15, and 17 to pin 6;excessive coupling may degrade stability.
2100 to 2500
1050 to 1250
1700 to 2100
MAX2721
850 to 1050Low
High
MAX2720
LO INPUT FREQUENCY RANGE (MHz)ENX2LOGIC LEVEL
Table 2. LO Input Frequency Range
MA
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0/M
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1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
20 ______________________________________________________________________________________
Table 3. PA Driver S-Parameters (VCC = 3.0V, TA = +25°C)
0.125
0.110
0.117
0.118
0.123
0.106
0.106
2.848
3.176
3.087
3.013
2.929
3.360
3.268
-97.8
-133.9
-153.1
-141.0
-144.9
-142.7
47.02500 0.425 40.9 0.015130.3
-138.9
80.4
71.7
63.5
55.4
96.2
2350
2300 0.456 75.9 0.051
0.462 67.9 0.042
87.4
2450
2400 0.447
135.8
59.7
135.3
0.031
0.437 51.6 0.026
132.9
132.2
2250
2200 0.475 88.0 0.055
0.473 84.2 0.046
139.0
136.9
0.1023.492 -138.0104.22150 0.470 97.2 0.066141.3
0.100
FREQUENCY(MHz)
S11 MAG S21 PHASE S22 MAG
0.105
0.093
0.093
0.091
0.096
S12 MAG
0.092
0.097
3.690
3.567
4.370
4.160
3.946
3.801
S21 MAG
4.708
4.389
S22 PHASE
-120.3
-128.8
-109.2
-118.4
-100.8
-111.0
-82.4
120.4
112.32100
2050 0.440 112.8 0.083
0.452 104.9 0.082
142.8
-99.5
153.5
144.3
135.2
128.4
S21 PHASE
178.1
142.9
1900
1850 0.418 138.2 0.123
0.449 129.7 0.095
161.7
2000
1950 0.421
149.4
128.7
145.3
0.082
0.425 121.2 0.091
140.1
142.8
1800
1700 0.321
S11 PHASE
164.7 0.162
0.383 147.2 0.142
151.6
152.0
0.0944.588 -90.3171.51750 0.347 154.2 0.158152.7
MA
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0/M
AX
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1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
______________________________________________________________________________________ 21
Typical Application Circuit
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
12
11
9
10
VCC
DROUT
GND
I+
I-
VCC
GND
GND
VCC
SHDN
DRIN
GND
PC
MODOUT
VCC
Q-
Q+
VCC
LO
ENX2
MAX2720MAX2721
0.1µF
VCC
470pF
0.1µF
8pF (5pF*)VCC
470pFVCC1000pF
100k
2.0pF
470pF
3.9nH
VCC
PA DRIVEROUTPUT
PA DRIVERINPUT
SHUTDOWNCONTROL
LO DOUBLERENABLE
VGA POWERCONTROL
I MODULATION Q MODULATION
LO INPUT
47pF
VCC
470pF
0.1µF
3pF
0.1µF
470pFVCC
1.0pF (27pF*)
470pF
1.5nH(1.2nH*)
0nH(3.3nH*)
VCC
MODOUTOUTPUT
10k
1000pF
100k
1000pF
*COMPONENT VALUE FOR MAX2721 0NLY.
MA
X2
72
0/M
AX
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21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
22 ______________________________________________________________________________________
Chip InformationTRANSISTOR COUNT: 1041
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
DRIN
GND
PC
MODOUTVCC
DROUT
GND
TOP VIEW
VCC
Q-
Q+I+
I-
VCC
GND
12
11
9
10
VCC
LOGND
VCC
MAX2720MAX2721
TSSOP-EP
SHDN
ENX2
Pin Configuration
MA
X2
72
0/M
AX
27
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1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
______________________________________________________________________________________ 23
Package Information
TSS
OP
.EP
S
MA
X2
72
0/M
AX
27
21
1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver
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.
24 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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.
24 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
NOTES
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