19-1606; Rev 0; 1/00
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
General Description
The MAX2720/MAX2721 are low-cost, high-performance,
direct I/Q modulators designed for use in wideband-
CDMA 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 pro-
vides 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.
o
RF Frequency Range
1.7GHz to 2.1GHz (MAX2720)
2.1GHz to 2.5GHz (MAX2721)
o
Integrated I/Q Modulator, LO Doubler, VGA, and
PA Driver
o
35dB VGA Gain Control Range
o
35dBc Sideband Suppression
o
30dBc Carrier Suppression
o
Low Supply Current
77mA (MAX2720), 86mA (MAX2721)
20mA Reduction with PA Driver Disabled
o
0.1µA Supply Current in Shutdown Mode
o
+2.7V to +3.3V Single-Supply Operation
Features
MAX2720/MAX2721
Ordering Information
PART
MAX2720EUP
MAX2721EUP
*Exposed
paddle.
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
20 TSSOP-EP*
20 TSSOP-EP*
Applications
Wireless Local Loop (WLL)
Wideband CDMA Systems
LMDS/MMDS
2.4GHz Broadband ISM Radios
DCS/PCS Base Stations
GND 1
DROUT 2
Functional Diagram
MAX2720/MAX2721
PA DRIVER
VGA
SHDN 3
V
CC
4
GND 5
90°
V
CC
6
I- 7
I+ 8
LO PHASE SHIFTER
0°
15 V
CC
14 Q-
13 Q+
12 V
CC
x2
LO DOUBLER
11 LO
Σ
18 PC
17 MODOUT
16 ENX2
20 DRIN
19 GND
Pin Configuration appears at end of data sheet.
V
CC
9
GND 10
BIAS
________________________________________________________________
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.
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
MAX2720/MAX2721
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ..............................................................-0.3V to +6V
ENX2, SHDN,
PC, I+, I-, Q+, Q-, LO,
DRIN to GND ........................................-0.3V to (V
CC
+ 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 (T
A
= +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
(V
CC
= +2.7V to +3.3V;
SHDN
= V
CC
;
ENX2
= GND; V
PC
= 0.5V; no input AC signals applied to I+, I-, Q+, Q-, LO, DRIN. MODOUT
and DROUT = V
CC,
T
A
= -40°C to +85°C. Typical values are at V
CC.
= +3V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
Supply Voltage
Supply Current
Supply Current with PA Driver
Disabled
Shutdown Supply Current
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Bias Current
PC Input Bias Current
0.5V < V
PC
< 2.5V
0.5V < V
PC
< 2.5V,
SHDN
= GND
-1
-5
2.5
MAX2720
MAX2721
MAX2720, DRIN = GND
MAX2721, DRIN = GND
SHDN
= GND
2.0
0.5
1
5
CONDITIONS
MIN
2.7
77
86
59
67
0.1
TYP
MAX
3.3
119
129
86
96
10
UNITS
V
mA
mA
µA
V
V
µA
µA
AC ELECTRICAL CHARACTERISTICS
(MAX2720/MAX2721 EV Kit, V
CC
= +3.0V,
SHDN
= V
CC
,
ENX2
= GND, V
PC
= 2.5V, input I/Q signals driven in quadrature, from a
1kΩ source impedance, single-ended, f
I+
= f
Q+
= 500kHz, V
I+
= V
Q+
= 200mVp-p, P
LO
= -13dBm, f
LO
= 950MHz (MAX2720), f
LO
=
1157.5MHz (MAX2721), P
DRIN
= -12dBm, f
DRIN
= 1900MHz (MAX2720), f
DRIN
= 2315MHz (MAX2721), MODOUT and DROUT ports
are matched to a 50Ω load, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
I/Q BASEBAND INPUTS
I/Q Input -1dB Bandwidth (Note 2)
I/Q Input -3dB Bandwidth (Note 2)
I/Q Differential Input Level
I/Q Gain Imbalance
I/Q Phase Imbalance
I/Q Input Resistance
I/Q Input Resistance Mismatch
I/Q Input Capacitance
Group Delay Ripple
Group Delay Mismatch
f
I
= f
Q
< BW
-3dB
, 0.5V < V
PC
< 2.5V
f
I
= f
Q
< BW
-3dB
, 0.5V < V
PC
< 2.5V
f
I
= f
Q
< BW
-1dB
f
I
= f
Q
< BW
-1dB
f
I
= f
Q
< BW
-1dB
100kHz < f
I+
= f
Q+
< 2MHz
100kHz < f
I
= f
Q
< 2MHz
1.6
14
20
40
200
±0.2
±1.0
2.0
18
5
1
1
630
MHz
MHz
mVp-p
dB
degrees
kΩ
Ω
pF
ns
ns
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2720/MAX2721 EV Kit, V
CC
= +3.0V,
SHDN
= V
CC
,
ENX2
= GND, V
PC
= 2.5V, input I/Q signals driven in quadrature, from a
1kΩ source impedance, single-ended, f
I+
= f
Q+
= 500kHz, V
I+
= V
Q+
= 200mVp-p, P
LO
= -13dBm, f
LO
= 950MHz (MAX2720), f
LO
=
1157.5MHz (MAX2721), P
DRIN
= -12dBm, f
DRIN
= 1900MHz (MAX2720), f
DRIN
= 2315MHz (MAX2721), MODOUT and DROUT ports
are matched to a 50Ω load, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
MODULATOR OUTPUT
Frequency Range (Note 3)
MAX2720
MAX2721
MAX2720, V
PC
= 2.5V,
ENX2
= V
CC
or GND,
T
A
= +25°C (Note 3)
MAX2721, V
PC
= 2.5V,
ENX2
= V
CC
or GND,
T
A
= +25°C (Note 3)
V
PC
= 2.5V,
T
A
= -40°C to +85°C
V
PC
= 0.5V,
ENX2
= V
CC
or GND
MAX2720
MAX2721
MAX2720
MAX2721
MAX2720
MAX2721
MAX2720
MAX2721
29
28
+1
+3
+8
+9
1700
2100
-12.5
-10.5
-8.5
-5.0
±1.0
±0.8
35
32
19
+5
+6
+14
+14
2:1
-141
26
24
20
30
28
33
31
25
40
35
50
V
CC
= +3.0V + 100mVp-p at 10kHz/300kHz
41
45
dBc
dB
dBc
dBc
-137
dBm/Hz
23
2100
2500
-6.0
dBm
-2.5
±1.8
±1.5
dB
dB
dB/V
dBm
dBm
MHz
CONDITIONS
MIN
TYP
MAX
UNITS
MAX2720/MAX2721
Output Power, High
Output Power Variation Over
Temperature
Power Control Range
PC Slope
Output 1dB Compression Point
Output Third-Order Intercept Point
(Note 4)
Output VSWR
Out-of-Band Noise Density
Carrier Suppression
Slope between V
PC
= 1V and V
PC
= 2V
V
PC
= 2.5V
V
PC
= 2.5V
0.5V < V
PC
< 2.5V
V
PC
= 2.5V, I/Q terminated in 50Ω
MAX2720, 0.5V < V
PC
< 2.5V
MAX2721
0.5V < V
PC
< 2.5V
V
PC
= 2.5V
V
PC
= 0.5V
MAX2720
MAX2721
Sideband Suppression
MODOUT to LO Input Isolation
Power-Supply Ripple Rejection
(Note 5)
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
ENX2
= V
CC
ENX2
= GND
ENX2
= V
CC
ENX2
= GND
ENX2
= V
CC
ENX2
= GND
ENX2
= V
CC
-16
850
1700
1050
2100
1.9:1
1.8:1
1.8:1
1.6:1
-10
dBm
1050
2100
1250
2500
MHz
_______________________________________________________________________________________
3
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
MAX2720/MAX2721
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2720/MAX2721 EV Kit, V
CC
= +3.0V,
SHDN
= V
CC
,
ENX2
= GND, V
PC
= 2.5V, input I/Q signals driven in quadrature, from a
1kΩ source impedance, single-ended, f
I+
= f
Q+
= 500kHz, V
I+
= V
Q+
= 200mVp-p, P
LO
= -13dBm, f
LO
= 950MHz (MAX2720), f
LO
=
1157.5MHz (MAX2721), P
DRIN
= -12dBm, f
DRIN
= 1900MHz (MAX2720), f
DRIN
= 2315MHz (MAX2721), MODOUT and DROUT ports
are matched to a 50Ω load, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
PA DRIVER
Frequency Range (Note 6)
Gain (Note 6)
Gain Variation Over Temperature
Noise Figure
Output 1dB Compression Point
Output Third-Order Intercept Point
Reverse Isolation
DROUT to LO Input Isolation
Input VSWR
Output VSWR
MAX2720
MAX2721
MAX2720
MAX2721
T
A
= -40°C to +85°C
MAX2720
MAX2721
MAX2720
MAX2721
MAX2720 (Note 7)
MAX2721 (Note 8)
+9.5
+8
+22
+20
MAX2720
MAX2721
1700
2100
11
8.5
13.5
11.5
±0.4
±0.3
2.4
2.6
+12.5
+11
+24
+24
19
65
1.5:1
1.5:1
2100
2500
15.5
15.5
±0.8
±0.8
MHz
dB
dB
dB
dBm
dBm
dB
dB
CONDITIONS
MIN
TYP
MAX
UNITS
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 V
PC
= 2.5V and T
A
= +25°C.
Note 4
IP3 measured with two tones, f
1
= 500kHz and f
2
= 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 T
A
= +25°C.
Note 7:
IP3 measured with two tones, f
1
= 1900MHz and f
2
= 1901MHz, at -18dBm each.
Note 8:
IP3 measured with two tones, f
1
= 2315MHz and f
2
= 2316MHz, at -18dBm each.
4
_______________________________________________________________________________________
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
MAX2720/MAX2721
Typical Operating Characteristics
(MAX2720/MAX2721 EV Kit, V
CC
= +3.0V,
SHDN
= V
CC
,
ENX2
= GND, V
PC
= 2.5V, input I/Q signals driven in quadrature, from a
1kΩ source impedance, single-ended, f
I+
= f
Q+
= 500kHz, V
I+
= V
Q+
= 200mVp-p, P
LO
= -13dBm, f
LO
= 950MHz (MAX2720), f
LO
=
1157.5MHz (MAX2721), P
DRIN
= -12dBm, f
DRIN
= 1900MHz (MAX2720), f
DRIN
= 2315MHz (MAX2721), MODOUT and DROUT ports
are matched to a 50Ω load, T
A
= +25°C, unless otherwise noted.) (Note 1)
MAX2720
SUPPLY CURRENT vs. SUPPLY VOLTAGE
WITH PA DRIVER ENABLED
MAX2720/21toc01
SUPPLY CURRENT vs. SUPPLY VOLTAGE
WITH PA DRIVER DISABLED
MAX2720/21toc02
MODULATOR OUTPUT POWER
vs. RF FREQUENCY
V
PC
= 2.5V
-10
OUTPUT POWER (dBm)
-20
-30
-40
-50
V
PC
= 0.5V
T
A
= +85°C
T
A
= -40°C
1700
1800
1900
2000
2100
RF FREQUENCY (MHz)
V
PC
= 1.5V
T
A
= +25°C
MAX2720/21toc04
100
90
80
SUPPLY CURRENT (mA)
70
60
50
40
30
20
10
0
2.7
ENX2 = GND
ENX2 = V
CC
2.8
2.9
3.0
3.1
3.2
T
A
= -40°C
T
A
= +85°C
T
A
= +25°C
100
90
80
SUPPLY CURRENT (mA)
70
60
50
40
30
20
10
0
ENX2 = GND
ENX2 = V
CC
2.7
2.8
2.9
3.0
3.1
3.2
T
A
= -40°C
T
A
= +25°C
DRIN = GND
T
A
= +85°C
0
-60
3.3
3.3
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
MODULATOR PERFORMANCE
vs. LO POWER (ENX2 = GND)
MAX2720/21toc05
MODULATOR PERFORMANCE
vs. LO POWER (ENX2 = V
CC
)
OUTPUT POWER
OUTPUT POWER (dBm) AND CARRIER
AND SIDEBAND SUPPRESSION (dBc)
-10
-20
-30
-40
-50
-60
-70
SIDEBAND
SUPPRESSION
-19
-17
-15
-13
-11
-9
-7
-5
CARRIER SUPPRESSION
MAX2720/21toc06
0
OUTPUT POWER (dBm) AND CARRIER
AND SIDEBAND SUPPRESSION (dBc)
OUTPUT POWER
-10
-20
-30
-40
SIDEBAND SUPPRESSION
-50
-60
-19
-17
-15
-13
-11
-9
-7
CARRIER SUPPRESSION
0
-5
LO POWER (dBm)
LO POWER (dBm)
_______________________________________________________________________________________
5
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