MAXIM MAX2720

19-1606; Rev 0; 1/00
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
The MAX2720/MAX2721 are low-cost, high-performance,
direct I/Q modulators designed for use in widebandCDMA and wireless local-loop (WLL) systems. Their
direct-upconversion architecture reduces system cost,
component count, and board space compared to
devices with dual-conversion architectures.
The MAX2720/MAX2721 include an I/Q modulator, a
variable gain amplifier (VGA), and a power amplifier
(PA) driver. The quadrature modulator accepts differential
baseband I/Q signals and directly modulates an RF
carrier in the 1.7GHz to 2.1GHz range (MAX2720) or
the 2.1GHz to 2.5GHz range (MAX2721). The VGA provides 35dB of output power control. The modulator’s
amplitude and phase balance yield 35dBc of sideband
suppression and 30dBc of carrier suppression. These
devices feature an LO frequency doubler that allows
the external LO source to operate at half-frequency or
full-frequency when disabled.
The MAX2720/MAX2721 operate from a single +2.7V to
+3.3V supply and require only 77mA (MAX2720) or
86mA (MAX2721) of supply current. An additional
20mA of supply current is saved by disabling the
stand-alone PA driver. A low-power shutdown mode
further reduces supply current to less than 0.1µA. The
device is packaged in the small 20-pin TSSOP-EP with
exposed paddle to improve RF performance.
Features
♦ RF Frequency Range
1.7GHz to 2.1GHz (MAX2720)
2.1GHz to 2.5GHz (MAX2721)
♦ Integrated I/Q Modulator, LO Doubler, VGA, and
PA Driver
♦ 35dB VGA Gain Control Range
♦ 35dBc Sideband Suppression
♦ 30dBc Carrier Suppression
♦ Low Supply Current
77mA (MAX2720), 86mA (MAX2721)
20mA Reduction with PA Driver Disabled
♦ 0.1µA Supply Current in Shutdown Mode
♦ +2.7V to +3.3V Single-Supply Operation
Ordering Information
TEMP. RANGE
PIN-PACKAGE
MAX2720EUP
PART
-40°C to +85°C
20 TSSOP-EP*
MAX2721EUP
-40°C to +85°C
20 TSSOP-EP*
*Exposed paddle.
Applications
Functional Diagram
Wireless Local Loop (WLL)
Wideband CDMA Systems
MAX2720/MAX2721
LMDS/MMDS
2.4GHz Broadband ISM Radios
DCS/PCS Base Stations
GND 1
20 DRIN
PA DRIVER
DROUT 2
19 GND
VGA
SHDN 3
18 PC
VCC 4
17 MODOUT
Σ
GND 5
16 ENX2
90°
I- 7
I+ 8
Pin Configuration appears at end of data sheet.
VCC 9
BIAS
LO PHASE SHIFTER
VCC 6
15 VCC
0°
14 Q13 Q+
12 VCC
x2
GND 10
11 LO
LO DOUBLER
________________________________________________________________ Maxim Integrated Products
1
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.
MAX2720/MAX2721
General Description
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
ABSOLUTE MAXIMUM RATINGS
VCC to GND ..............................................................-0.3V to +6V
ENX2, SHDN, PC, I+, I-, Q+, Q-, LO,
DRIN to GND ........................................-0.3V to (VCC + 0.3V)
ENX2, SHDN Continuous Current.....................................±10mA
PC Continuous Current.....................................................±10mA
I+ to I-, Q+ to Q- ....................................................................±2V
MODOUT, 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°C
Junction Temperature ......................................................+150°C
Storage Temperature Range ............................ -65°C to +150°C
Lead Temperature (soldering 10s) ................................. +300°C
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
(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. MODOUT
and DROUT = VCC, TA = -40°C to +85°C. Typical values are at VCC. = +3V, TA = +25°C, unless otherwise noted.)
PARAMETER
CONDITIONS
TYP
MAX
UNITS
3.3
V
MAX2720
77
119
MAX2721
86
129
Supply Current with PA Driver
Disabled
MAX2720, DRIN = GND
59
86
MAX2721, DRIN = GND
67
96
Shutdown Supply Current
Logic Input High Voltage
SHDN = GND
0.1
10
2.7
Supply Voltage
Supply Current
MIN
2.0
Logic Input Low Voltage
-1
Logic Input Bias Current
PC Input Bias Current
-5
0.5V < VPC < 2.5V
0.5V < VPC < 2.5V, SHDN = GND
mA
mA
µA
V
0.5
V
1
µA
5
2.5
µA
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 a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
14
20
MAX
UNITS
I/Q BASEBAND INPUTS
I/Q Input -1dB Bandwidth (Note 2)
I/Q Input -3dB Bandwidth (Note 2)
40
I/Q Differential Input Level
200
MHz
MHz
630
mVp-p
I/Q Gain Imbalance
fI = fQ < BW-3dB, 0.5V < VPC < 2.5V
±0.2
dB
I/Q Phase Imbalance
fI = fQ < BW-3dB, 0.5V < VPC < 2.5V
±1.0
degrees
I/Q Input Resistance
fI = fQ < BW-1dB
2.0
kΩ
I/Q Input Resistance Mismatch
fI = fQ < BW-1dB
18
Ω
I/Q Input Capacitance
fI = fQ < BW-1dB
5
pF
Group Delay Ripple
100kHz < fI+ = fQ+ < 2MHz
1
ns
Group Delay Mismatch
100kHz < fI = fQ < 2MHz
1
ns
2
1.6
_______________________________________________________________________________________
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
MODULATOR OUTPUT
Frequency Range (Note 3)
Output Power, High
MAX2720
1700
2100
MAX2721
2100
2500
MAX2720, VPC = 2.5V, ENX2 = VCC or GND,
TA = +25°C (Note 3)
-12.5
-8.5
-6.0
MAX2721, VPC = 2.5V, ENX2 = VCC or GND,
TA = +25°C (Note 3)
-10.5
-5.0
-2.5
dBm
Output Power Variation Over
Temperature
VPC = 2.5V,
TA = -40°C to +85°C
MAX2720
±1.0
±1.8
MAX2721
±0.8
±1.5
Power Control Range
VPC = 0.5V,
ENX2 = VCC or GND
MAX2720
29
35
MAX2721
28
32
PC Slope
Slope between VPC = 1V and VPC = 2V
Output 1dB Compression Point
VPC = 2.5V
Output Third-Order Intercept Point
(Note 4)
VPC = 2.5V
Output VSWR
0.5V < VPC < 2.5V
Out-of-Band Noise Density
VPC = 2.5V, I/Q terminated in 50Ω
Sideband Suppression
MAX2721
0.5V < VPC < 2.5V
19
MAX2720
+1
+5
MAX2721
+3
+6
MAX2720
+8
+14
MAX2721
+9
+14
-141
26
33
VPC = 2.5V
24
31
VPC = 0.5V
20
25
MAX2720
30
40
MAX2721
28
35
50
MODOUT to LO Input Isolation
Power-Supply Ripple Rejection
(Note 5)
dB
dB
23
dB/V
dBm
dBm
2:1
MAX2720, 0.5V < VPC < 2.5V
Carrier Suppression
MHz
-137
dBc
dBc
45
41
VCC = +3.0V + 100mVp-p at 10kHz/300kHz
dBm/Hz
dB
dBc
LO BUFFER, LO FREQUENCY DOUBLER, QUADRATURE GENERATOR
MAX2720
LO Frequency Range (Note 3)
MAX2721
MAX2720
LO Input VSWR
MAX2721
LO Input Power (Note 3)
ENX2 = GND
850
1050
ENX2 = VCC
1700
2100
ENX2 = GND
1050
1250
ENX2 = VCC
2100
2500
ENX2 = GND
1.9:1
ENX2 = VCC
1.8:1
ENX2 = GND
1.8:1
ENX2 = VCC
1.6:1
-16
MHz
-10
dBm
_______________________________________________________________________________________
3
MAX2720/MAX2721
AC ELECTRICAL CHARACTERISTICS (continued)
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
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 a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
PA DRIVER
Frequency Range (Note 6)
Gain (Note 6)
Gain Variation Over Temperature
Noise Figure
Output 1dB Compression Point
Output Third-Order Intercept Point
MAX2720
1700
2100
MAX2721
2100
2500
MAX2720
11
13.5
15.5
MAX2721
8.5
11.5
15.5
MAX2720
±0.4
±0.8
MAX2721
±0.3
±0.8
TA = -40°C to +85°C
MAX2720
2.4
MAX2721
2.6
MAX2720
+9.5
+12.5
MAX2721
+8
+11
MAX2720 (Note 7)
+22
+24
MAX2721 (Note 8)
+20
+24
MHz
dB
dB
dB
dBm
dBm
Reverse Isolation
19
dB
DROUT to LO Input Isolation
65
dB
Input VSWR
1.5:1
Output VSWR
1.5:1
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.
4
_______________________________________________________________________________________
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2720
SUPPLY CURRENT vs. SUPPLY VOLTAGE
WITH PA DRIVER DISABLED
60
TA = +85°C
40
TA = +25°C
30
20
2.8
50
TA = +25°C
30
TA = -40°C
0
2.9
3.0
3.1
3.2
2.7
3.3
2.8
-30
VPC = 0.5V
-40
2.9
TA = +85°C
TA = -40°C
-60
3.0
3.1
3.2
3.3
1700
1800
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
0
OUTPUT POWER
-10
1900
2000
2100
RF FREQUENCY (MHz)
MODULATOR PERFORMANCE
vs. LO POWER (ENX2 = GND)
MODULATOR PERFORMANCE
vs. LO POWER (ENX2 = VCC)
-20
-30
VPC = 1.5V
-20
-50
ENX2 = GND
ENX2 = VCC
10
CARRIER SUPPRESSION
-40
SIDEBAND SUPPRESSION
-50
-60
0
OUTPUT POWER
OUTPUT POWER (dBm) AND CARRIER
AND SIDEBAND SUPPRESSION (dBc)
2.7
60
MAX2720/21toc05
0
70
40
TA = +25°C
VPC = 2.5V
-10
20
ENX2 = GND
ENX2 = VCC
10
TA = +85°C
80
TA = -40°C
0
MAX2720/21toc06
50
DRIN = GND
90
OUTPUT POWER (dBm)
70
OUTPUT POWER (dBm) AND CARRIER
AND SIDEBAND SUPPRESSION (dBc)
SUPPLY CURRENT (mA)
80
100
MAX2720/21toc02
90
SUPPLY CURRENT (mA)
MAX2720/21toc01
100
MODULATOR OUTPUT POWER
vs. RF FREQUENCY
MAX2720/21toc04
SUPPLY CURRENT vs. SUPPLY VOLTAGE
WITH PA DRIVER ENABLED
-10
-20
-30
CARRIER SUPPRESSION
-40
-50
SIDEBAND
SUPPRESSION
-60
-70
-19
-17
-15
-13
-11
LO POWER (dBm)
-9
-7
-5
-19
-17
-15
-13
-11
-9
-7
-5
LO POWER (dBm)
_______________________________________________________________________________________
5
MAX2720/MAX2721
Typical Operating Characteristics
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 a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2720
2.1GHz
-20
-25
-30
-35
-40
-15
-20
2.1GHz
-25
1.9GHz
-30
-50
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
PC VOLTAGE (V)
MODULATOR OUTPUT POWER
vs. PC VOLTAGE (ENX2 = VCC)
MODULATOR CARRIER SUPPRESSION
vs. PC VOLTAGE (ENX2 = VCC)
-10
1.7GHz
-15
-20
2.1GHz
-25
-30
-35
-40
0
-10
-20
2.1GHz
-30
1.7GHz
-40
-50
1.9GHz
-70
0.5
1.0
1.5
2.0
PC VOLTAGE (V)
6
2.5
3.0
0
0.5
1.0
1.5
2.0
2.5
0
-5
-10
3.0
-15
-20
-25
1.9GHz
-30
1.7GHz
-35
-40
-45
-45
0
1.7GHz
MODULATOR SIDEBAND SUPPRESSION
vs. PC VOLTAGE (ENX2 = VCC)
-60
-50
-40
3.0
MAX2720/21toc11
1.9GHz
CARRIER SUPPRESSION (dBc)
MAX2720/21toc10
0
2.1GHz
-30
PC VOLTAGE (V)
PC VOLTAGE (V)
-5
1.9GHz
-60
0
SIDEBAND SUPPRESSION (dBc)
0.5
-20
1.7GHz
-40
0
-10
-50
-35
-45
MAX2720/21toc09
-5
-10
0
SIDEBAND SUPPRESSION (dBc)
1.7GHz
0
MAX2720/21toc08
-10
MAX2720/21toc07
1.9GHz
CARRIER SUPPRESSION (dBc)
OUTPUT POWER (dBm)
0
-5
-15
MODULATION SIDEBAND SUPPRESSION
vs. PC VOLTAGE (ENX2 = GND)
MODULATOR CARRIER SUPPRESSION
vs. PC VOLTAGE (ENX2 = GND)
MAX2720/21toc12
MODULATOR OUTPUT POWER
vs. PC VOLTAGE (ENX2 = GND)
OUTPUT POWER (dBm)
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
2.1GHz
-50
0
0.5
1.0
1.5
2.0
PC VOLTAGE (V)
2.5
3.0
0
0.5
1.0
1.5
2.0
PC VOLTAGE (V)
_______________________________________________________________________________________
2.5
3.0
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2720
MODULATOR CARRIER SUPPRESSION
vs. PC VOLTAGE (ENX2 = GND)
-15
TA = +25°C
-20
TA = +85°C
-25
-30
-35
-40
-15
-20
TA = +25°C
TA = -40°C
-25
-30
-35
-45
-10
-20
TA = -40°C
-30
TA = +85°C
-40
-55
TA = +85°C
TA = +25°C
-40
-50
0.5
1.0
1.5
2.0
2.5
0.5
1.0
1.5
2.0
2.5
3.0
0
0.5
1.0
1.5
2.0
2.5
3.0
PC VOLTAGE (V)
PC VOLTAGE (V)
PC VOLTAGE (V)
MODULATOR OUTPUT POWER
vs. PC VOLTAGE (ENX2 = VCC)
MODULATOR CARRIER SUPPRESSION
vs. PC VOLTAGE (ENX2 = VCC)
MODULATOR SIDEBAND SUPPRESSION
vs. PC VOLTAGE (ENX2 = VCC)
-10
-15
TA = +25°C
-20
TA = +85°C
-25
-30
-35
-40
0
-10
-20
TA = +85°C
-30
-40
-50
-45
-60
-50
-70
0.5
1.0
1.5
2.0
PC VOLTAGE (V)
2.5
3.0
TA = -40°C
TA = +25°C
0
MAX2720/21toc18
TA = -40°C
-10
SIDEBAND SUPRESSION (dBc)
MAX2720/21toc16
0
-5
0
-60
0
3.0
CARRIER SUPRESSION (dBc)
0
OUTPUT POWER (dBm)
-10
0
MAX2720/21toc15
-5
MAX2720/21toc17
OUTPUT POWER (dBm)
-10
0
MAX2720/21toc14
TA = -40°C
CARRIER SUPPRESSION (dBc)
MAX2720/21toc13
0
-5
MODULATOR SIDEBAND SUPPRESSION
vs. PC VOLTAGE (ENX2 = GND)
SIDEBAND SUPPRESSION (dBc)
MODULATOR OUTPUT POWER
vs. PC VOLTAGE (ENX2 = GND)
-20
TA = +85°C
-30
-40
-50
TA = -40°C
TA = +25°C
-60
0
0.5
1.0
1.5
2.0
PC VOLTAGE (V)
2.5
3.0
0
0.5
1.0
1.5
2.0
2.5
3.0
PC VOLTAGE (V)
_______________________________________________________________________________________
7
MAX2720/MAX2721
Typical Operating Characteristics (continued)
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 a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2720
VPC = 0.5V
VPC = 2.0V
-30
VPC = 1.5V
-40
-50
MAX2720 toc20
-10
VPC = 1.0V
VPC = 2.5V
-20
VPC = 0.5V
-30
-40
0
VPC = 2.0V
VPC = 1.5V
-20
100
1000
10,000
10
100
MODULATOR OUTPUT IP3
vs. PC VOLTAGE
VSWR
5
0
TA = -40°C
-5
-10
100
1000
10,000
INPUT LEVEL (mVp-p)
LO PORT VSWR
vs. LO FREQUENCY (ENX2 = GND)
LO PORT VSWR
vs. LO FREQUENCY (ENX2 = VCC)
2.8
2.4
2.4
2.0
2.0
VSWR
TA = +85°C
TA = +25°C
10
10
10,000
MAX2720-24
15
1000
2.8
MAX2720/21toc22
20
-40
INPUT LEVEL (mVp-p)
INPUT LEVEL (mVp-p)
25
VPC = 2.0V
VPC = 1.5V
-60
-60
10
-30
VPC = 0.5V
VPC = 2.5V
-50
-50
-60
VPC = 1.0V
-10
1.6
1.8
1.2
1.4
MAX2720-25
VPC = 1.0V
10
OUTPUT POWER (dBm)
-10
VPC = 2.5V
0
OUTPUT POWER (dBm)
0
OUTPUT POWER (dBm)
10
MAX2720 toc19
10
-20
MODULATOR OUTPUT POWER
vs. INPUT LEVEL (TA = +85°C)
MODULATOR OUTPUT POWER
vs. INPUT LEVEL (TA = +25°C)
MAX2720 toc21
MODULATOR OUTPUT POWER
vs. INPUT LEVEL (TA = -40°C)
OUTPUT IP3 (dBm)
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
-15
-20
-25
-30
0.5
1.0
1.5
2.0
PC VOLTAGE (V)
8
1.0
1.0
0
2.5
3.0
850
890
930
970
FREQUENCY (MHz)
1010
1050
1700
1780
1860
1940
FREQUENCY (MHz)
_______________________________________________________________________________________
2020
2100
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
MAX2720
PA DRIVER OUTPUT IP3
vs. SUPPLY VOLTAGE
TA = +25°C
TA = +85°C
12
11
10
2.7
2.8
2.9
3.0
3.1
3.2
27
TA = +85°C
26
25
24
TA = -40°C
23
20
19
18
OUTPUT P1dB (dBm)
13
TA = +25°C
28
OUTPUT IP3 (dBm)
14
29
MAX2720/21toc28
TA = -40°C
GAIN (dB)
30
MAX2720/21toc27
15
PA DRIVER OUTPUT P1dB
vs. SUPPLY VOLTAGE
17
16
15
13
12
21
11
20
10
2.7
2.8
2.9
3.0
3.1
3.2
TA = +85°C
14
22
3.3
MAX2720/21toc29
PA DRIVER GAIN vs.
SUPPLY VOLTAGE
3.3
TA = +25°C
TA = -40°C
2.7
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
2.8
2.9
3.0
3.1
3.2
3.3
SUPPLY VOLTAGE (V)
Page 1
PA DRIVER OUTPUT IP3
vs. FREQUENCY
GAIN (dB)
14
12
TA = +25°C
10
TA = +85°C
8
28
6
TA = +85°C
TA = +25°C
27
26
25
TA = -40°C
24
23
22
4
1700
1800
1900
2000
RF FREQUENCY (MHz)
2100
18
17
16
15
TA = -40°C
14
13
TA = +25°C
TA = +85°C
11
20
0
19
12
21
2
20
OUTPUT P1dB (dBm)
TA = -40°C
16
OUTPUT IP3 (dBm)
18
29
PA DRIVER OUTPUT P1dB COMPRESSION
POINT vs. FREQUENCY
MAX2720/21toc32
MAX2720/21toc30
20
30
MAX2720/21toc31
PA DRIVER GAIN
vs. RF FREQUENCY
1700
1800
1900
FREQUENCY (MHz)
2000
2100
10
1700
1800
1900
2000
2100
FREQUENCY (MHz)
_______________________________________________________________________________________
9
MAX2720/MAX2721
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 a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
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 a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2720
20
MAX2720/21toc33
5.0
4.0
3.5
3.0
2.5
2.0
TA = +85°C
TA = +25°C
TA = +25°C
15
TA = +85°C
OUTPUT POWER (dBm)
4.5
1.5
10
MAX2720/21toc34
PA DRIVER OUTPUT POWER
vs. INPUT POWER
PA DRIVER NOISE FIGURE
vs. FREQUENCY
NOISE FIGURE (dB)
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
TA = -40°C
5
0
-5
1.0
-10
0.5
TA = -40°C
0
1700
1800
1900
FREQUENCY (MHz)
10
2000
-15
2100
-25 -20 -15 -10
-5
0
5
INPUT POWER (dBm)
______________________________________________________________________________________
10
15
20
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2721
70
60
50
TA = -40°C
TA = +85°C
80
70
60
TA = +25°C
50
40
40
ENX2 = GND
ENX2 = VCC
30
-10
2.9
3.0
3.1
3.2
2.7
3.3
2.8
2.9
3.1
3.2
VPC = 0.5V
-35
2200
2300
2400
2500
RF FREQUENCY (MHz)
MODULATOR PERFORMANCE
vs. LO POWER (ENX2 = VCC)
0
OUTPUT POWER
-10
-15
-20
SIDEBAND SUPPRESSION
-30
-35
TA= +85°C
-30
2100
3.3
MODULATOR PERFORMANCE
vs. LO POWER (ENX2 = GND)
-25
TA= +25°C
-25
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
-5
-20
-50
3.0
CARRIER SUPPRESSION
-40
0
OUTPUT POWER (dBm) AND CARRIER AND
SIDEBAND SUPPRESSION (dBc)
2.8
MAX2720/21toc39
2.7
VPC = 1.5V
-15
-45
20
20
TA= -40°C
-40
TA = -40°C
ENX2 = GND
ENX2 = VCC
30
VPC = 2.5V
OUTPUT POWER
-5
-10
MAX2720/21toc40
TA = +25°C
90
0
-5
OUTPUT POWER (dBm)
80
DRIN = GND
100
SUPPLY CURRENT (mA)
90
OUTPUT POWER (dBm) AND CARRIER AND
SIDEBAND SUPPRESSION (dBc)
SUPPLY CURRENT (mA)
100
110
MAX2720/21toc36
TA = +85°C
110
120
MAX2720/21toc35
120
MODULATOR OUTPUT POWER
vs. RF FREQUENCY
MAX2720 toc38
SUPPLY CURRENT vs. SUPPLY VOLTAGE
WITH PA DRIVER DISABLED
SUPPLY CURRENT vs. SUPPLY VOLTAGE
WITH PA DRIVER ENABLED
-15
-20
-25
SIDEBAND SUPPRESSION
-30
CARRIER SUPPRESSION
-35
-40
-19
-17
-15 -13
-11 -9
RF FREQUENCY (MHz)
-7
-5
-19
-17
-15
-13
-11
-9
-7
-5
LO POWER (dBm)
______________________________________________________________________________________
11
MAX2720/MAX2721
Typical Operating Characteristics (continued)
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 a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2721
-15
-20
-25
-30
-35
-10
-15
-20
2.5GHz
-25
-30
0
-5
SIDEBAND SUPRESSION (dBc)
2.3GHz
2.5GHz
-5
2.3GHz
-35
-10
-15
-20
-25
2.5GHz
-30
-35
2.1GHz
2.1GHz
-40
0.5
1.0
1.5
2.0
2.5
3.0
2.3GHz
-40
0
0.5
1.0
1.5
2.0
2.5
3.0
0
0.5
1.0
1.5
2.0
2.5
PC VOLTAGE (V)
PC VOLTAGE (V)
PC VOLTAGE (V)
MODULATOR OUTPUT POWER
vs. PC VOLTAGE (ENX2 = VCC)
MODULATOR CARRIER SUPRESSION
vs. PC VOLTAGE (ENX2 = VCC)
MODULATOR SIDEBAND SUPRESSION
vs. PC VOLTAGE (ENX2 = VCC)
-15
-20
-25
-30
-35
-10
-15
2.3GHz
-20
2.5GHz
-25
-30
-35
2.1GHz
-40
0
3.0
MAX2721 TOC46
2.3GHz
2.5GHz
-10
0
-5
-5
SIDEBAND SUPRESSION (dBc)
2.1GHz
CARRIER SUPRESSION (dBc)
0
-5
MAX2721 TOC44
0
-40
MAX2721 TOC45
OUTPUT POWER (dBm)
-5
0
MAX2720/21toc42
2.1GHz
CARRIER SUPPRESSION (dBm)
MAX2720/21toc41
0
-10
SIDEBAND SUPRESSION vs. PC VOLTAGE
(ENX2 = GND)
CARRIER SUPPRESSION vs. PC VOLTAGE
(ENX2 = GND)
MAX2721 TOC43
MODULATOR OUTPUT POWER
vs. PC VOLTAGE (ENX2 = GND)
OUTPUT POWER (dBm)
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
-10
-15
-20
-25
2.3GHz
2.5GHz
-30
-35
-40
2.1GHz
-45
0.5
1.0
1.5
2.0
PC VOLTAGE (V)
12
-40
-45
0
2.5
3.0
0
0.5
1.0
1.5
2.0
PC VOLTAGE (V)
2.5
3.0
0
0.5
1.0
1.5
2.0
PC VOLTAGE (V)
______________________________________________________________________________________
2.5
3.0
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2721
TA = +85°C
-15
TA = +25°C
-20
-25
-30
MAX2721 TOC48
-5
-10
-15
-20
TA = -40°C
-25
-35
-30
-40
-35
TA = +85°C
-5
0.5
1.0
1.5
2.0
2.5
3.0
-20
TA = -40°C
-25
TA = +25°C
-30
TA = +85°C
-40
0
0.5
1.0
1.5
2.0
2.5
0
3.0
0.5
1.0
1.5
2.0
2.5
3.0
PC VOLTAGE (V)
MODULATOR OUTPUT POWER
vs. PC VOLTAGE (ENX2 = VCC)
MODULATOR CARRIER SUPRESSION
vs. PC VOLTAGE (ENX2) = VCC
MODULATOR SIDEBAND SUPPRESSION
vs. PC VOLTAGE (ENX2 = VCC)
TA = +85°C
-15
TA = +25°C
-25
-30
-5
-10
-20
-25
-35
-40
-40
1.0
1.5
2.0
PC VOLTAGE (V)
2.5
3.0
TA = +25°C
-30
-35
0.5
TA = -40°C
-15
TA = +85°C
0
-5
SIDEBAND SUPPRESSION (dBc)
-10
MAX2721 TOC51
MAX2721 TOC450
TA = -40°C
0
MAX2721 TOC52
PC VOLTAGE (V)
-5
0
-15
PC VOLTAGE (V)
0
-20
-10
-35
TA = +25°C
0
OUTPUT POWER (dBm)
0
SIDEBAND SUPRESSION (dBc)
-10
0
CARRIER SUPRESSION (dBc)
TA = -40°C
CARRIER SUPPRESSION (dBc)
OUTPUT POWER (dBm)
MAX2721 TOC47
0
-5
MODULATOR SIDEBAND SUPRESSION
vs. PC VOLTAGE (ENX2 = GND)
MODULATOR CARRIER SUPRESSION
vs. PC VOLTAGE (ENX2 = GND)
MAX2721 TOC49
MODULATOR OUTPUT POWER
vs. PC VOLTAGE (ENX2 = GND)
-10
-15
-20
TA = -40°C
-25
-30
-35
TA = +85°C
-40
0
0.5
TA = +25°C
1.0
1.5
2.0
PC VOLTAGE (V)
2.5
3.0
0
0.5
1.0
1.5
2.0
2.5
3.0
PC VOLTAGE (V)
______________________________________________________________________________________
13
MAX2720/MAX2721
Typical Operating Characteristics (continued)
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 a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2721
MODULATOR OUTPUT POWER
vs. INPUT LEVEL (TA = +25°C)
VPC = 1.0V
VPC = 0.5V
VPC = 2.5V
VPC = 2.0V
VPC = 1.5V
-40
-40
-50
-50
-60
-60
10
100
1000
MAX2721 TOC54
VPC = 1.5V
VPC = 2.5V
-20
VPC = 2.0V
-30
VPC = 1.5V
-40
VPC = 1.0V
VPC = 1.0V
-50
VPC = 0.5V
VPC = 0.5V
-60
10
10,000
-10
100
1000
10,000
10
100
1000
10,000
INPUT LEVEL (mVp-p)
INPUT LEVEL (mVp-p)
INPUT LEVEL (mVp-p)
MODULATOR OUTPUT IP3
vs. PC VOLTAGE
MODULATOR OUTPUT P1dB
COMPRESSION POINT vs. PC VOLTAGE
LO PORT VSWR vs. LO FREQUENCY
(ENX2 = VCC)
20
TA = +85°C
15
TA = +25°C
5
TA = -40°C
0
25
MAX2721 TOC56
25
10
VPC = 2.0V
-30
0
20
15
-5
-10
-15
TA = -40°C
2.4
10
5
2.0
0
TA = +85°C
-5
TA = +25°C
1.8
-10
-15
-20
2.6
MAX2721toc58
-30
VPC = 2.5V
-20
VSWR
-20
0
-10
10
MAX2720/21toc57
-10
20
OUTPUT POWER (dBm)
OUTPUT POWER (dBm)
0
10
OUTPUT P1dB (dBm)
OUTPUT POWER (dBm)
10
1.4
-20
-25
-25
-30
0
0.5
1.0
1.5
2.0
INPUT LEVEL (mVp-p)
14
20
MAX2721 TOC53
20
MODULATOR OUTPUT POWER
vs. INPUT LEVEL (TA = +85°C)
MAX2721 TOC55
MODULATOR OUTPUT POWER
vs. INPUT LEVEL (TA = -40°C)
OUTPUT IP3 (dBm)
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
2.5
3.0
1.0
0.5
1.0
1.5
PC VOLTAGE (V)
2.0
2.5
2100
2180
2260
2340
FREQUENCY (MHz)
______________________________________________________________________________________
2420
2500
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
(MAX2720/MAX2721 EV Kit, VCC = +3.0V, SHDN = VCC, ENX2 = GND, VPC = 2.5V, input I/Q signals driven in quadrature, from a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2721
GAIN (dB)
VSWR
1.6
13
TA = +25°C
TA = -40°C
12
28
1.4
TA = +85°C
1130
1170
1210
2.7
17
16
16
2.9
3.0
3.1
3.2
15
12
14
10
TA = +85°C
12
TA = -40°C
14
GAIN (dB)
OUTPUT P1dB (dBm)
2.8
18
MAX2720/21toc63
18
10
TA = -40°C
2.8
2.9
3.0
2.7
3.1
SUPPLY VOLTAGE (V)
3.2
3.3
2.9
3.0
3.1
3.2
3.3
PA DRIVER OUTPUT IP3
vs. FREQUENCY
TA = +25°C
8
2.8
SUPPLY VOLTAGE (V)
TA = +85°C
6
29
28
TA = +25°C
27
TA = +85°C
26
25
TA = -40°C
24
23
2
22
0
21
-2
8
2.7
TA = -40°C
23
3.3
4
TA = +25°C
9
24
PA DRIVER GAIN
vs. RF FREQUENCY
PA DRIVER OUTPUT P1dB
vs. SUPPLY VOLTAGE
11
25
SUPPLY VOLTAGE (V)
FREQUENCY (MHz)
13
26
20
10
1250
OUTPUT IP3 (dBm)
1090
TA = +85°C
21
MAX2720/21toc64
1050
TA = +25°C
27
22
11
1.0
MAX2720/21toc62
29
OUTPUT IP3 (dBm)
14
1.8
30
MAX2721 TOC61
15
MAX2721toc59
2.0
PA DRIVER OUTPUT IP3
vs. SUPPLY VOLTAGE
PA DRIVER GAIN vs. SUPPLY VOLTAGE
MAX2720/21toc65
LO PORT VSWR vs. FREQUENCY
(ENX2 = GND)
20
2100
2200
2300
2400
RF FREQUENCY (MHz)
2500
2100
2200
2300
2400
2500
FREQUENCY (MHz)
______________________________________________________________________________________
15
MAX2720/MAX2721
Typical Operating Characteristics (continued)
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 a
1kΩ 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 ports
are matched to a 50Ω load, TA = +25°C, unless otherwise noted.) (Note 1)
MAX2721
PA DRIVER OUTPUT P1dB
vs. FREQUENCY
PA DRIVER NOISE FIGURE
vs. FREQUENCY
16
9
8
NOISE FIGURE (dB)
TA = +85°C
14
10
12
10
TA = -40°C
8
TA = +25°C
6
7
6
5
4
2
2
1
0
0
2200
2300
2400
2500
TA = +85°C
TA = -40°C
3
4
2100
MAX2720/21toc67
18
MAX2720/21toc66
20
OUTPUT P1dB (dBm)
TA = +25°C
2100
2200
FREQUENCY (MHz)
2300
2400
FREQUENCY (MHz)
2.0
TA = +25°C
15
TA = +85°C
MAX2720/21toc68
PA DRIVER OUTPUT POWER
vs. INPUT POWER
OUTPUT POWER (dBm)
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
TA = -40°C
10
5
-10
-15
-25 -20 -15 -10
-5
0
-5
10
15
20
INPUT POWER (dBm)
16
______________________________________________________________________________________
2500
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
PIN
NAME
1, 5, 10, 19, EP
GND
2
DROUT
3
SHDN
Shutdown Control Input. Drive with a logic-level high to enable the device. Drive with a logiclevel low to disable the device. Bypass with a 1000pF capacitor to ground, as close to the
pin as possible to minimize the amount of external noise coupled onto the control line.
4, 6, 9, 12, 15
VCC
Supply Voltage Input. Bypass to ground with the specified capacitor as close to the pin as
possible. (See Typical Application Circuit.)
7, 8
I-, I+
In-Phase Differential Input Ports. Requires DC-blocking capacitors. See Typical Application
Circuit for recommended component values.
11
LO
Local Oscillator input. Internally matched to 50Ω over the operating frequency band.
Requires a DC-blocking capacitor. See Typical Application Circuit for recommended component values.
13, 14
Q+, Q-
Quadrature Differential Input Ports. Requires DC-blocking capacitors. See Typical Application
Circuit for recommended component values.
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-level
high 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 minimize
noise coupled into the control line.
17
MODOUT
Modulator Open-Collector Output Port. Requires an external matching network and a pullup inductor to VCC for proper biasing. See Typical Application Circuit for recommended
component values.
18
PC
Modulator Power Control Input. Apply a voltage between 0.5V to 2.5V to vary the output
power of the I/Q modulator over a 30dB range. Bypass with a 1000pF capacitor to ground
as close to the pin as possible to minimize noise on the control line.
DRIN
PA Driver Amplifier Input Port. Requires an external matching network and a DC-blocking
capacitor that can be part of the matching network. See Typical Application Circuit for recommended component values. Connect to ground to disable the PA Driver and reduce
supply current.
20
FUNCTION
Ground. Connect to ground plane with lowest inductance path. Solder exposed paddle
evenly to the board ground plane.
PA Driver Open-Collector Output Port. Requires an external matching network and a pullup inductor to VCC for proper biasing. See Typical Application Circuit for recommended
component values.
Detailed Description
The MAX2720/MAX2721 upconvert in-phase (I) and
quadrature (Q) baseband signals directly to RF
frequencies of 1700MHz to 2100MHz (MAX2720) or
2100MHz to 2500MHz (MAX2721). They are designed
for wideband-CDMA and WLL systems where direct I/Q
modulation of the RF carrier reduces system cost, component count, and board space compared to
dual-conversion architectures.
Internally, the MAX2720/MAX2721 include an I/Q modulator, a variable gain amplifier (VGA), and a PA driver.
Separate modulator output and PA driver input ports
allow insertion of a bandpass filter between the modulator
and PA driver for increased noise rejection. Disable the
stand-alone PA driver to reduce current consumption.
A low-power shutdown mode further reduces current
consumption to less than 0.1µA. Additionally, a logiclevel control disables or enables an internal frequency
doubler that allows the external LO to run at full or half
frequency.
______________________________________________________________________________________
17
MAX2720/MAX2721
Pin Description
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
I/Q Modulator
The MAX2720/MAX2721 modulator is composed of a pair
of matched double-balanced mixers, an active LO quadrature generator, and a summing amplifier. The pair of
mixers accept differential I/Q baseband signals that
directly modulate the internal 0° and 90° LO signals
applied to the I/Q mixers. An external LO source drives
an internal LO quadrature generator that shifts the phase
of the LO signal applied to the Q mixer by 90° relative to
the LO signal applied to the I channel mixer. The modulated output of the I/Q mixers is summed together, and
the undesired sideband is suppressed.
The I+, I-, Q+, and Q- input ports feature high-linearity
buffer amplifiers with a -1dB bandwidth of 20MHz and
a -3dB bandwidth of 38MHz (1kΩ I/Q source impedance), and accept differential input voltages up to
630mVp-p. Input bandwith can be extended to beyond
100MHz by lowering the I/Q source impedance. The
ports are internally biased and therefore require DCblocking capacitors. For single-ended operation,
bypass the I- and Q- ports with a capacitor to ground
equal in value to the DC-blocking capacitors used on
the I+ and Q+ ports. See the Typical Application Circuit
for 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 vary
the output power of the modulator over a 32dB span.
The open-collector MODOUT output requires a pull-up
inductor to VCC for proper biasing, an external matching
network for optimum power transfer, and a DC-blocking
capacitor. Since the MAX2720/MAX2721 are optimized
for different frequency ranges, they require different
output matching networks. See the MAX2720 and
MAX2721 Typical Application Circuit for recommended
component values. See Table 1 for matching to other
frequencies.
LO Buffer and LO Frequency Doubler
The MAX2720/MAX2721 feature an internal LO frequency
doubler that allows the external LO source to run at full or
half frequency (Table 2). Operating the LO at half frequency reduces injection-pulling of the voltage-controlled oscillator (VCO) from the PA, and reduces the
complexity of designing a high-frequency VCO. An
internal two-pole bandpass filter is integrated before
the LO phase-shift network to help reduce LO harmonic
content and spurious mixing.
To enable the LO frequency doubler, drive ENX2 to a
logic-level low and operate the external LO source at
half the RF carrier frequency. To disable the LO
frequency doubler, drive ENX2 to a logic-level high and
run 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 a
VSWR of better than 2:1 over the specified LO input
frequency range. Since the port is internally terminated
with 50Ω, it requires a DC-blocking capacitor. See the
Typical Applications Circuits for recommended component values. For optimum performance, drive the LO
port with an input power of -16dBm to -10dBm. Driving
the LO port with lower input power levels may affect
quadrature performance, while higher input powers
may increase LO leakage.
PA Driver Amplifier
The PA driver provides a gain of 13.5dB for the
MAX2720 and 11.5dB for the MAX2721. The DRIN
input port requires an external matching network and a
Table 1. VGA MODOUT S22 Parameters (VCC = 3.0V, VPC = 2.5V, TA = +25°C)
MAX2720
18
MAX2721
FREQUENCY
(MHz)
S22 MAG
S22 PHASE
(degrees)
FREQUENCY
(MHz)
S22 MAG
S22 PHASE
(degrees)
1700
0.914
-66.6
2100
0.861
-86.5
1750
0.909
-68.9
2150
0.861
-91.3
1800
0.896
-71.0
2200
0.832
-93.8
1850
0.884
-73.0
2250
0.811
-94.4
1900
0.871
-74.6
2300
0.807
-94.7
1950
0.868
75.4
2350
0.834
-94.8
2000
0.878
-77.1
2400
0.866
-97.1
2050
0.892
-79.6
2450
0.891
-100.5
2100
0.897
82.5
2500
0.905
-104.5
______________________________________________________________________________________
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
ENX2
LOGIC LEVEL
LO INPUT FREQUENCY RANGE (MHz)
MAX2720
MAX2721
Low
850 to 1050
1050 to 1250
High
1700 to 2100
2100 to 2500
DC-blocking capacitor that can be part of the matching
network. The DROUT open-collector output port
requires an external matching network and a pull-up
inductor to VCC for proper biasing. The pull-up inductor
is incorporated as part of the matching network. See
the MAX2720 and MAX2721 Typical Application Circuit
for recommended component values. Refer to Table 3
for 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 ground
and leave pin 2 unconnected.
Shutdown
Apply a logic-level high to the SHDN pin to enable the
MAX2720/MAX2721. Apply a logic-level low voltage to
disable the device and reduce supply current to less
than 0.1µA.
Applications Information
Layout Considerations
A properly designed PC board is an essential part of
any RF circuit. A ground plane is essential. Keep RF
signal lines as short as possible to reduce losses, radiation, and inductance. Use separate, low-inductance
vias to the ground plane for each pin. For best performance, solder the exposed pad on the bottom of the
device package evenly to the board ground plane.
Remove the ground plane under the external VCO and
lowpass filters to reduce the effects of parasitic capaci-
tance. In direct I/Q modulator applications, radiated
power from the PA can couple into the VCO tank. To
reduce PA injection-pulling, the external VCO should be
housed in a separate shielded compartment if possible.
Power-Supply, Logic, and PC
Input Bypassing
Proper voltage supply bypassing is essential for high-frequency circuit stability. With the exception of pin 6,
bypass all VCC pins with a 470pF capacitor as close to
the VCC pins as possible. The decoupling capacitor for
pin 6 also serves as part of an on-chip matching network,
so it should be chosen to resonate out series inductance
on the board. Some empirical adjustment may yield
increased output power. See the MAX2720/MAX2721
Typical Application Circuit for suggested values.
Bypass the ENX2, SHDN, and PC inputs with a 1000pF
capacitor to ground to minimize noise injected into the
device. Use a series resistor (10kΩ typ) to further
reduce coupling of high-frequency signals into the
device.
Voltage supply layout is also critical to achieve optimum
performance. The IC has several RF processing stages
that use the various V CC pins, and while they have
on-chip decoupling, off-chip interaction between them
may degrade gain, linearity, carrier suppression, and
output power control range. The supplies associated
with pins 2, 6, 15 (MAX2721 only), and 17 lie directly in
the RF signal path. Pins 4, 12, and 15 carry LO signal
currents, so it is important to keep them from interacting
with the RF signal path to prevent poor carrier suppression. The VGA generates discarded signal currents on
pin 4, which also need to be kept away from the signal
path supplies. Because there is a great deal of gain
following from the first RF stage, it is also important to
prevent coupling from pins 2, 4, 15, and 17 to pin 6;
excessive coupling may degrade stability.
______________________________________________________________________________________
19
MAX2720/MAX2721
Table 2. LO Input Frequency Range
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
Table 3. PA Driver S-Parameters (VCC = 3.0V, TA = +25°C)
FREQUENCY
(MHz)
S11 MAG
S11 PHASE
S21 MAG
S21 PHASE
S12 MAG
S21 PHASE
S22 MAG
S22 PHASE
1700
0.321
151.6
4.708
178.1
0.092
164.7
0.162
-82.4
1750
0.347
152.7
4.588
171.5
0.094
154.2
0.158
-90.3
1800
0.383
152.0
4.389
161.7
0.097
147.2
0.142
-99.5
1850
0.418
149.4
4.370
153.5
0.093
138.2
0.123
-109.2
1900
0.449
145.3
4.160
144.3
0.093
129.7
0.095
-118.4
1950
0.421
140.1
3.946
135.2
0.091
128.7
0.082
-100.8
2000
0.425
142.8
3.801
128.4
0.096
121.2
0.091
-111.0
2050
0.440
142.8
3.690
120.4
0.100
112.8
0.083
-120.3
2100
0.452
142.9
3.567
112.3
0.105
104.9
0.082
-128.8
2150
0.470
141.3
3.492
104.2
0.102
97.2
0.066
-138.0
2200
0.475
139.0
3.360
96.2
0.106
88.0
0.055
-142.7
2250
0.473
136.9
3.268
87.4
0.106
84.2
0.046
-138.9
2300
0.456
135.8
3.176
80.4
0.110
75.9
0.051
-133.9
2350
0.462
135.3
3.087
71.7
0.117
67.9
0.042
-153.1
2400
0.447
132.9
3.013
63.5
0.118
59.7
0.031
-141.0
2450
0.437
132.2
2.929
55.4
0.123
51.6
0.026
-144.9
2500
0.425
130.3
2.848
47.0
0.125
40.9
0.015
-97.8
20
______________________________________________________________________________________
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
VCC
470pF
3pF
1
3.9nH
PA DRIVER
INPUT
DRIN 20
GND
VCC
2.0pF
PA DRIVER
OUTPUT
SHUTDOWN
CONTROL
2
DROUT
GND 19
3
1000pF
VGA POWER
CONTROL
10k
100k
PC 18
SHDN
VCC
1000pF
470pF
1.5nH
(1.2nH*)
1.0pF (27pF*)
470pF
4
VCC
MODOUT 17
5
GND
ENX2 16
0nH
(3.3nH*)
100k
VCC
1000pF
8pF (5pF*)
MAX2720
MAX2721
MODOUT
OUTPUT
LO DOUBLER
ENABLE
VCC
470pF
VCC 15
6
VCC
7
I-
Q- 14
8
I+
Q+ 13
0.1µF
0.1µF
0.1µF
0.1µF
I MODULATION
Q MODULATION
VCC
VCC
9
VCC
VCC 12
470pF
470pF
10 GND
LO INPUT
LO 11
47pF
*COMPONENT VALUE FOR MAX2721 0NLY.
______________________________________________________________________________________
21
MAX2720/MAX2721
Typical Application Circuit
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
MAX2720/MAX2721
Pin Configuration
Chip Information
TRANSISTOR COUNT: 1041
TOP VIEW
GND 1
20 DRIN
DROUT 2
19 GND
SHDN 3
18 PC
17 MODOUT
VCC 4
GND 5
VCC 6
MAX2720
MAX2721
16 ENX2
15 VCC
I- 7
14 Q-
I+ 8
13 Q+
VCC 9
12 VCC
GND 10
11 LO
TSSOP-EP
22
______________________________________________________________________________________
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
TSSOP.EPS
______________________________________________________________________________________
23
MAX2720/MAX2721
Package Information
MAX2720/MAX2721
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
NOTES
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.
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.