19-2588; Rev 0; 9/02
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
General Description
The MAX9981 dual high-linearity mixer integrates a local
oscillator (LO) switch, LO buffer, LO splitter, and two
active mixers. On-chip baluns allow for single-ended RF
and LO inputs. The active mixers eliminate the need for
an additional IF amplifier because the mixer provides a
typical overall conversion gain of 2.1dB.
The MAX9981 active mixers are optimized to meet the
demanding requirements of GSM850, GSM900, and
CDMA850 base-station receivers. These mixers provide
exceptional linearity with an input IP3 of greater than
+27dBm. The integrated LO driver allows for a wide
range of LO drive levels from -5dBm to +5dBm. In addi-
tion, the built-in high-isolation switch enables rapid LO
selection of less than 250ns, as needed for GSM trans-
ceiver designs.
The MAX9981 is available in a 36-pin QFN package
(6mm
✕
6mm) with an exposed paddle, and is specified
over the -40°C to +85°C extended temperature range.
o
+27.3dBm Input IP3
o
+13.6dBm Input 1dB Compression Point
o
825MHz to 915MHz RF Frequency Range
o
70MHz to 170MHz IF Frequency Range
o
725MHz to 1085MHz LO Frequency Range
o
2.1dB Conversion Gain
o
10.8dB Noise Figure
o
42dB Channel-to-Channel Isolation
o
-5dBm to +5dBm LO Drive
o
+5V Single-Supply Operation
o
Built-In LO Switch with 52dB LO1 to LO2 Isolation
o
ESD Protection
o
Integrated RF and LO Baluns for Single-Ended
Inputs
Features
MAX9981
Applications
GSM850/GSM900 2G and 2.5G EDGE Base-
Station Receivers
Cellular cdmaOne™ and cdma2000™ Base-
Station Receivers
TDMA and Integrated Digital Enhanced Network
(iDEN)™ Base-Station Receivers
Digital and Spread-Spectrum Communication
Systems
Microwave Point-to-Point Links
RFMAIN
TAPMAIN
MAINBIAS
GND
GND
GND
DIVBIAS
TAPDIV
1
2
3
4
5
6
7
8
9
Ordering Information
PART
MAX9981EGX-T
TEMP RANGE
PIN-PACKAGE
-40°C to +85°C 36 QFN-EP* (6mm
×
6mm)
*EP
= Exposed paddle.
Pin Configuration/
Functional Diagram
IFMAIN+
TOP VIEW
V
CC
GND
GND
IFMAIN-
GND
V
CC
GND
29
31
35
34
36
33
32
30
28
27 LO2
26 GND
25 GND
24 GND
23 LOSEL
22 GND
21 V
CC
20 GND
19 LO1
MAX9981
cdmaOne is a trademark of CDMA Development Group.
cdma2000 is a trademark of Telecommunications Industry
Association.
iDEN is a trademark of Motorola, Inc.
RFDIV
15
11
12
10
IFDIV+
13
14
16
17
GND
GND
GND
GND
6mm x 6mm QFN-EP
________________________________________________________________
Maxim Integrated Products
IFDIV-
GND
V
CC
V
CC
18
GND
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
MAX9981
ABSOLUTE MAXIMUM RATINGS
V
CC
........................................................................-0.3V to +5.5V
IFMAIN+, IFMAIN-, IFDIV+, IFDIV-,
MAINBIAS, DIVBIAS, LOSEL..................-0.3V to (V
CC
+ 0.3V)
TAPMAIN, TAPDIV ..............................................................+5.5V
MAINBIAS, DIVBIAS Current ................................................5mA
RFMAIN, RFDIV, LO1, LO2 Input Power ........................+20dBm
Continuous Power Dissipation (T
A
= +70°C)
36-Pin QFN (derate 33mW/°C above +70°C)..............2200mW
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
(Typical
Application Circuit,
V
CC
= +4.75V to +5.25V, no RF signals applied, all RF inputs and outputs terminated with 50Ω,
267Ω resistors connected from MAINBIAS and DIVBIAS to GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at
V
CC
= +5.0V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
Supply Voltage
Supply Current
Input High Voltage
Input Low Voltage
LOSEL Input Current
SYMBOL
V
CC
I
CC
V
IH
V
IL
I
LOSEL
-5
CONDITIONS
MIN
4.75
260
3.5
0.4
+5
TYP
5.00
291
MAX
5.25
325
UNITS
V
mA
V
V
µA
AC ELECTRICAL CHARACTERISTICS
(Typical
Application Circuit,
V
CC
= +4.75V to +5.25V, P
LO
= -5dBm to +5dBm, f
RF
= 825MHz to 915MHz, f
LO
= 725MHz to 1085MHz,
T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
CC
= +5.0V, P
RF
= -5dBm, P
LO
= 0dBm, f
RF
= 870MHz,
f
LO
= 770MHz, T
A
= +25°C, unless otherwise noted.) (Notes 1, 2)
PARAMETER
RF Frequency
LO Frequency
IF Frequency
LO Drive Level
SYMBOL
f
RF
f
LO
f
IF
P
LO
V
CC
= +5.0V,
f
IF
= 100MHz,
low-side injection,
P
RF
= 0dBm,
P
LO
= -5dBm
Cellular band,
f
RF
= 825MHz to
850MHz
GSM band,
f
RF
= 880MHz
to 915MHz
Must meet RF and LO frequency range. IF
matching components affect IF frequency
range.
CONDITIONS
MIN
825
725
70
-5
2.7
dB
2.1
±0.6
53
dB
dB
TYP
MAX
915
1085
170
+5
UNITS
MHz
MHz
MHz
dBm
Conversion Gain (Note 3)
G
C
Gain Variation from Nominal
Conversion Loss from LO to IF
f
RF
= 825MHz to 915MHz, 3σ
Inject P
IN
= -20dBm at f
LO
+ 100MHz into
LO port. Measure 100MHz at IF port as
P
OUT
. No RF signal at RF port.
100MHz IF,
low-side
injection
Cellular band,
f
RF
= 825MHz to 850MHz
GSM band,
f
RF
= 880MHz to 915MHz
10.8
dB
11.9
Noise Figure
NF
2
_______________________________________________________________________________________
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
AC ELECTRICAL CHARACTERISTICS (continued)
(Typical
Application Circuit,
V
CC
= +4.75V to +5.25V, P
LO
= -5dBm to +5dBm, f
RF
= 825MHz to 915MHz, f
LO
= 725MHz to 1085MHz,
T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
CC
= +5.0V, P
RF
= -5dBm, P
LO
= 0dBm, f
RF
= 870MHz,
f
LO
= 770MHz, T
A
= +25°C, unless otherwise noted.) (Notes 1, 2)
PARAMETER
Input 1dB Compression Point
Input Third-Order Intercept Point
2 RF - 2 LO Spur Rejection
3 RF - 3 LO Spur Rejection
Maximum LO Leakage at RF Port
Maximum LO Leakage at IF Port
Minimum RF to IF Isolation
LO1 to LO2 Isolation
SYMBOL
P
1dB
IIP3
2
×
2
3
×
3
CONDITIONS
Low-side injection
P
LO
= -5dBm to +5dBm (Notes 3, 4)
f
RF
= 915MHz, f
LO
= 815MHz,
f
SPUR
= 865MHz, P
RF
= -5dBm
f
RF
= 915MHz, f
LO
= 815MHz,
f
SPUR
= 848.3MHz, P
RF
= -5dBm
P
LO
= -5dBm to +5dBm,
f
LO
= 725MHz to 1100MHz
P
LO
= -5dBm to +5dBm,
f
LO
= 725MHz to 1100MHz
P
LO
= -5dBm to +5dBm,
f
RF
= 825MHz to 915MHz
f
RF
= 825MHz to 915MHz, P
LO1
= P
LO2
=
+5dBm, f
IF
= 100MHz (Note 5)
P
RFMAIN
= -5dBm, RFDIV
terminated with 50Ω.
Measured power at IFDIV
relative to IFMAIN.
P
RFDIV
= -5dBm, RFMAIN
terminated with 50Ω.
Measured power at
IFMAIN relative to IFDIV.
Main
Diversity
MIN
TYP
13.6
27.3
53.3
43.2
79.7
-42
-30.6
18
52
MAX
UNITS
dBm
dBm
dBc
dBc
dBm
dBm
dB
dB
MAX9981
39.5
dBc
42
Minimum Channel Isolation
f
RF
= 825MHz
to 915MHz,
f
LO
= 725MHz
to 1085MHz
LO Switching Time
RF Return Loss
LO Return Loss
IF Return Loss
50% of LOSEL to IF settled within 2°
LO port selected
LO port unselected
RF and LO terminated into 50Ω,
f
IF
= 100MHz (Note 6)
250
25
19
14.3
15
ns
dB
dB
dB
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Guaranteed by design and characterization.
All limits reflect losses of external components. Output measurements taken at IF OUT of
Typical Application Circuit.
Production tested.
Two tones at 1MHz spacing, -5dBm per tone at RF port.
Measured at IF port at IF frequency. f
LO1
and f
LO2
are offset by 1MHz.
IF return loss can be optimized by external matching components.
_______________________________________________________________________________________
3
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
MAX9981
Typical Operating Characteristics
(Typical
Application Circuit,
V
CC
= 5.0V, P
RF
= -5dBm, P
LO
= 0dBm, T
A
= +25°C, unless otherwise noted.)
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc01
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc02
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
f
IF
= 100MHz
MAIN MIXER
MAX9981 toc03
5
T
A
= -40°C
f
IF
= 100MHz
MAIN MIXER
5
f
IF
= 100MHz
MAIN MIXER
5
4
CONVERSION GAIN (dB)
4
CONVERSION GAIN (dB)
4
CONVERSION GAIN (dB)
3
3
3
2
T
A
= +85°C
T
A
= +25°C
0
820
840
860
880
900
920
RF FREQUENCY (MHz)
2
P
LO
= -5dBm, 0dBm, +5dBm
1
2
V
CC
= 4.75V, 5.0V, 5.25V
1
1
0
820
840
860
880
900
920
RF FREQUENCY (MHz)
0
820
840
860
880
900
920
RF FREQUENCY (MHz)
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc04
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc05
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
f
IF
= 120MHz
MAIN MIXER
MAX9981 toc06
5
f
IF
= 120MHz
MAIN MIXER
T
A
= -40°C
5
f
IF
= 120MHz
MAIN MIXER
5
4
CONVERSION GAIN (dB)
4
CONVERSION GAIN (dB)
4
CONVERSION GAIN (dB)
3
3
3
2
2
P
LO
= -5dBm, 0dBm, +5dBm
1
2
V
CC
= 4.75V, 5.0V, 5.25V
1
1
T
A
= +85°C
T
A
= +25°C
0
0
820
840
860
880
900
920
820
840
860
880
900
920
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
880
900
920
0
820
840
860
RF FREQUENCY (MHz)
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc07
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc08
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
f
IF
= 100MHz
MAIN MIXER
P
RF
= -5dBm
MAX9981 toc09
80
T
A
= +85°C
75
2 RF - 2 LO RESPONSE (dBc)
70
65
60
55
T
A
= -40°C
50
45
820
840
860
880
900
T
A
= +25°C
f
IF
= 100MHz
MAIN MIXER
P
RF
= -5dBm
85
2 RF - 2 LO RESPONSE (dBc)
75
2 RF - 2 LO RESPONSE (dBc)
f
IF
= 100MHz
MAIN MIXER
P
RF
= -5dBm
80
75
70
65
60
55
50
45
V
CC
= 4.75V, 5.0V, 5.25V
P
LO
= -5dBm
65
P
LO
= 0dBm
55
P
LO
= +5dBm
45
920
820
840
860
880
900
920
820
840
860
880
900
920
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
4
_______________________________________________________________________________________
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
Typical Operating Characteristics (continued)
(Typical
Application Circuit,
V
CC
= 5.0V, P
RF
= -5dBm, P
LO
= 0dBm, T
A
= +25°C, unless otherwise noted.)
MAX9981
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc10
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc11
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
f
IF
= 100MHz
DIVERSITY MIXER
P
RF
= -5dBm
55
MAX9981 toc12
MAX9981 toc18
MAX9981 toc15
60
T
A
= +85°C
2 RF - 2 LO RESPONSE (dBc)
55
f
IF
= 100MHz
DIVERSITY MIXER
P
RF
= -5dBm
60
P
LO
= +5dBm
2 RF - 2 LO RESPONSE (dBc)
55
f
IF
= 100MHz
DIVERSITY MIXER
P
RF
= -5dBm
60
50
50
2 RF - 2 LO RESPONSE (dBc)
50
45
T
A
= +25°C
T
A
= -40°C
45
P
LO
= 0dBm
P
LO
= -5dBm
45
V
CC
= 4.75V, 5.0V, 5.25V
40
820
840
860
880
900
920
RF FREQUENCY (MHz)
40
820
840
860
880
900
920
RF FREQUENCY (MHz)
40
820
840
860
880
900
920
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc13
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
f
IF
= 120MHz
MAIN MIXER
P
RF
= -5dBm
MAX9981 toc14
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
60
f
IF
= 120MHz
MAIN MIXER
P
RF
= -5dBm
70
f
IF
= 120MHz
MAIN MIXER
P
RF
= -5dBm
60
2 LO - 2 RF RESPONSE (dBc)
2 LO - 2 RF RESPONSE (dBc)
60
T
A
= +85°C
56
P
LO
= -5dBm
54
P
LO
= 0dBm
2 LO - 2 RF RESPONSE (dBc)
65
58
58
56
V
CC
= 5.25V
55
T
A
= +25°C
50
T
A
= -40°C
45
820
840
860
880
900
920
RF FREQUENCY (MHz)
54
V
CC
= 4.75, 5.0V
52
P
LO
= +5dBm
50
820
840
860
880
900
920
RF FREQUENCY (MHz)
52
50
820
840
860
880
900
920
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc16
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
f
IF
= 120MHz
DIVERSITY MIXER
P
RF
= -5dBm
P
LO
= +5dBm
47.5
45.0
42.5
40.0
P
LO
= -5dBm
37.5
42
820
840
860
880
900
920
MAX9981 toc17
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
46
f
IF
= 120MHz
DIVERSITY MIXER
P
RF
= -5dBm
47
46
2 LO - 2 RF RESPONSE (dBc)
45
44
T
A
= +25°C
43
42
T
A
= -40°C
41
40
820
840
860
T
A
= +85°C
2 LO - 2 RF RESPONSE (dBc)
2 LO - 2 RF RESPONSE (dBc)
f
IF
= 120MHz
DIVERSITY MIXER
P
RF
= -5dBm
52.5
50.0
P
LO
= 0dBm
45
44
V
CC
= 5.25V
43
V
CC
= 4.75V, 5.0V
880
900
920
820
840
860
880
900
920
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
_______________________________________________________________________________________
5
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