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 -40C to +85C extended temperature range.
Applications
GSM850/GSM900 2G and 2.5G EDGE Base-
Station Receivers
Cellular cdmaOneTM and cdma2000TM Base-
Station Receivers
TDMA and Integrated Digital Enhanced Network
(iDEN)TM Base-Station Receivers
Digital and Spread-Spectrum Communication
Systems
Microwave Point-to-Point Links
Features
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
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
________________________________________________________________ Maxim Integrated Products
1
Ordering Information
19-2588; Rev 0; 9/02
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.
PART
TEMP RANGE
PIN-PACKAGE
MAX9981EGX-T
-40C to +85C
36 QFN-EP* (6mm
6mm)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
28
29
30
31
32
33
34
35
36
19
20
21
22
23
24
25
26
27
LO2
GND
GND
GND
MAINBIAS
DIVBIAS
TAPDIV
TAPMAIN
RFMAIN
RFDIV
GND
GND
GND
GND
GND
V
CC
V
CC
GND
GND
V
CC
GND
GND
GND
IFDIV+
IFDIV
-
V
CC
IFMAIN+
IFMAIN-
LO1
LOSEL
GND
GND
GND
GND
GND
V
CC
MAX9981
6mm x 6mm QFN-EP
TOP VIEW
Pin Configuration/
Functional Diagram
*EP = Exposed paddle.
cdmaOne is a trademark of CDMA Development Group.
cdma2000 is a trademark of Telecommunications Industry
Association.
iDEN is a trademark of Motorola, Inc.
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, V
CC
= +4.75V to +5.25V, no RF signals applied, all RF inputs and outputs terminated with 50
,
267
resistors connected from MAINBIAS and DIVBIAS to GND, T
A
= -40C to +85C, unless otherwise noted. Typical values are at
V
CC
= +5.0V, T
A
= +25C, unless otherwise noted.)
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.
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
= +70C)
36-Pin QFN (derate 33mW/C above +70C)..............2200mW
Operating Temperature Range ...........................-40C to +85C
Junction Temperature ......................................................+150C
Storage Temperature Range .............................-65C to +150C
Lead Temperature (soldering, 10s) .................................+300C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage
V
CC
4.75
5.00
5.25
V
Supply Current
I
CC
260
291
325
mA
Input High Voltage
V
IH
3.5
V
Input Low Voltage
V
IL
0.4
V
LOSEL Input Current
I
LOSEL
-5
+5
A
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
= -40C to +85C, 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
= +25C, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RF Frequency
f
RF
825
915
MHz
LO Frequency
f
LO
725
1085
MHz
IF Frequency
f
IF
Must meet RF and LO frequency range. IF
matching components affect IF frequency
range.
70
170
MHz
LO Drive Level
P
LO
-5
+5
dBm
Cellular band,
f
RF
= 825MHz to
850MHz
2.7
Conversion Gain (Note 3)
G
C
V
CC
= +5.0V,
f
IF
= 100MHz,
low-side injection,
P
RF
= 0dBm,
P
LO
= -5dBm
GSM band,
f
RF
= 880MHz
to 915MHz
2.1
dB
Gain Variation from Nominal
f
RF
= 825MHz to 915MHz, 3
0.6
dB
Conversion Loss from LO to IF
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.
53
dB
Cellular band,
f
RF
= 825MHz to 850MHz
10.8
Noise Figure
NF
100MHz IF,
low-side
injection
GSM band,
f
RF
= 880MHz to 915MHz
11.9
dB
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
_______________________________________________________________________________________
3
Note 1: Guaranteed by design and characterization.
Note 2: All limits reflect losses of external components. Output measurements taken at IF OUT of Typical Application Circuit.
Note 3: Production tested.
Note 4: Two tones at 1MHz spacing, -5dBm per tone at RF port.
Note 5: Measured at IF port at IF frequency. f
LO1
and f
LO2
are offset by 1MHz.
Note 6: IF return loss can be optimized by external matching components.
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
= -40C to +85C, 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
= +25C, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Input 1dB Compression Point
P
1dB
Low-side injection
13.6
dBm
Input Third-Order Intercept Point
IIP3
P
LO
= -5dBm to +5dBm (Notes 3, 4)
27.3
dBm
Main
53.3
2 RF - 2 LO Spur Rejection
2
2
f
RF
= 915MHz, f
LO
= 815MHz,
f
SPUR
= 865MHz, P
RF
= -5dBm
Diversity
43.2
dBc
3 RF - 3 LO Spur Rejection
3
3
f
RF
= 915MHz, f
LO
= 815MHz,
f
SPUR
= 848.3MHz, P
RF
= -5dBm
79.7
dBc
Maximum LO Leakage at RF Port
P
LO
= -5dBm to +5dBm,
f
LO
= 725MHz to 1100MHz
-42
dBm
Maximum LO Leakage at IF Port
P
LO
= -5dBm to +5dBm,
f
LO
= 725MHz to 1100MHz
-30.6
dBm
Minimum RF to IF Isolation
P
LO
= -5dBm to +5dBm,
f
RF
= 825MHz to 915MHz
18
dB
LO1 to LO2 Isolation
f
RF
= 825MHz to 915MHz, P
LO1
= P
LO2
=
+5dBm, f
IF
= 100MHz (Note 5)
52
dB
P
RFMAIN
= -5dBm, RFDIV
terminated with 50
.
Measured power at IFDIV
relative to IFMAIN.
39.5
Minimum Channel Isolation
f
RF
= 825MHz
to 915MHz,
f
LO
= 725MHz
to 1085MHz
P
RFDIV
= -5dBm, RFMAIN
terminated with 50
.
Measured power at
IFMAIN relative to IFDIV.
42
dBc
LO Switching Time
50% of LOSEL to IF settled within 2
250
ns
RF Return Loss
25
dB
LO port selected
19
LO Return Loss
LO port unselected
14.3
dB
IF Return Loss
RF and LO terminated into 50
,
f
IF
= 100MHz (Note 6)
15
dB
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
4
_______________________________________________________________________________________
Typical Operating Characteristics
(Typical Application Circuit, V
CC
= 5.0V, P
RF
= -5dBm, P
LO
= 0dBm, T
A
= +25C, unless otherwise noted.)
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc01
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900
880
860
840
1
2
3
4
5
0
820
920
f
IF
= 100MHz
MAIN MIXER
T
A
= -40
C
T
A
= +85
C
T
A
= +25
C
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc02
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900
880
860
840
1
2
3
4
5
0
820
920
f
IF
= 100MHz
MAIN MIXER
P
LO
= -5dBm, 0dBm, +5dBm
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc03
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900
880
860
840
1
2
3
4
5
0
820
920
f
IF
= 100MHz
MAIN MIXER
V
CC
= 4.75V, 5.0V, 5.25V
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc04
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900
880
860
840
1
2
3
4
5
0
820
920
f
IF
= 120MHz
MAIN MIXER
T
A
= -40
C
T
A
= +85
C
T
A
= +25
C
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc05
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900
880
860
840
1
2
3
4
5
0
820
920
f
IF
= 120MHz
MAIN MIXER
P
LO
= -5dBm, 0dBm, +5dBm
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc06
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900
880
860
840
1
2
3
4
5
0
820
920
f
IF
= 120MHz
MAIN MIXER
V
CC
= 4.75V, 5.0V, 5.25V
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc07
RF FREQUENCY (MHz)
2 RF - 2 LO RESPONSE (dBc)
900
880
860
840
50
55
60
65
70
75
80
45
820
920
f
IF
= 100MHz
MAIN MIXER
P
RF
= -5dBm
T
A
= +85
C
T
A
= +25
C
T
A
= -40
C
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc08
RF FREQUENCY (MHz)
2 RF - 2 LO RESPONSE (dBc)
900
880
860
840
55
65
75
85
45
820
920
P
LO
= -5dBm
P
LO
= 0dBm
P
LO
= +5dBm
f
IF
= 100MHz
MAIN MIXER
P
RF
= -5dBm
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc09
RF FREQUENCY (MHz)
2 RF - 2 LO RESPONSE (dBc)
900
880
860
840
50
55
60
65
70
75
80
45
820
920
f
IF
= 100MHz
MAIN MIXER
P
RF
= -5dBm
V
CC
= 4.75V, 5.0V, 5.25V
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
_______________________________________________________________________________________
5
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc10
RF FREQUENCY (MHz)
2 RF - 2 LO RESPONSE (dBc)
900
880
860
840
45
50
55
60
40
820
920
f
IF
= 100MHz
DIVERSITY MIXER
P
RF
= -5dBm
T
A
= +85
C
T
A
= +25
C
T
A
= -40
C
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc11
RF FREQUENCY (MHz)
2 RF - 2 LO RESPONSE (dBc)
900
880
860
840
45
50
55
60
40
820
920
f
IF
= 100MHz
DIVERSITY MIXER
P
RF
= -5dBm
P
LO
= +5dBm
P
LO
= 0dBm
P
LO
= -5dBm
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc12
RF FREQUENCY (MHz)
2 RF - 2 LO RESPONSE (dBc)
900
880
860
840
45
50
55
60
40
820
920
f
IF
= 100MHz
DIVERSITY MIXER
P
RF
= -5dBm
V
CC
= 4.75V, 5.0V, 5.25V
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc13
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE (dBc)
900
880
860
840
50
55
65
60
70
45
820
920
f
IF
= 120MHz
MAIN MIXER
P
RF
= -5dBm
T
A
= +85
C
T
A
= +25
C
T
A
= -40
C
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc14
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE (dBc)
900
880
860
840
52
54
58
56
60
50
820
920
f
IF
= 120MHz
MAIN MIXER
P
RF
= -5dBm
P
LO
= -5dBm
P
LO
= +5dBm
P
LO
= 0dBm
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc15
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE (dBc)
900
880
860
840
52
54
58
56
60
50
820
920
f
IF
= 120MHz
MAIN MIXER
P
RF
= -5dBm
V
CC
= 5.25V
V
CC
= 4.75, 5.0V
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc16
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE (dBc)
900
880
860
840
41
42
43
46
45
44
47
40
820
920
f
IF
= 120MHz
DIVERSITY MIXER
P
RF
= -5dBm
T
A
= +85
C
T
A
= +25
C
T
A
= -40
C
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc17
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE (dBc)
900
880
860
840
40.0
42.5
45.0
50.0
47.5
52.5
37.5
820
920
f
IF
= 120MHz
DIVERSITY MIXER
P
RF
= -5dBm
P
LO
= +5dBm
P
LO
= -5dBm
P
LO
= 0dBm
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc18
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE (dBc)
900
880
860
840
43
44
45
46
42
820
920
f
IF
= 120MHz
DIVERSITY MIXER
P
RF
= -5dBm
V
CC
= 5.25V
V
CC
= 4.75V, 5.0V
Typical Operating Characteristics (continued)
(Typical Application Circuit, V
CC
= 5.0V, P
RF
= -5dBm, P
LO
= 0dBm, T
A
= +25C, unless otherwise noted.)
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