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 addition, the built-in high-isolation switch enables rapid LO
selection of less than 250ns, as needed for GSM transceiver 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.
Applications
GSM850/GSM900 2G and 2.5G EDGE BaseStation Receivers
Cellular cdmaOne™ and cdma2000™ BaseStation Receivers
TDMA and Integrated Digital Enhanced Network
(iDEN)™ Base-Station Receivers
Digital and Spread-Spectrum Communication
Systems
Microwave Point-to-Point Links
Features
♦ +27.3dBm Input IP3
♦ +13.6dBm Input 1dB Compression Point
♦ 825MHz to 915MHz RF Frequency Range
♦ 70MHz to 170MHz IF Frequency Range
♦ 725MHz to 1085MHz LO Frequency Range
♦ 2.1dB Conversion Gain
♦ 10.8dB Noise Figure
♦ 42dB Channel-to-Channel Isolation
♦ -5dBm to +5dBm LO Drive
♦ +5V Single-Supply Operation
♦ Built-In LO Switch with 52dB LO1 to LO2 Isolation
♦ ESD Protection
♦ 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.
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.
PART TEMP RANGE PIN-PACKAGE
MAX9981EGX-T -40°C to +85°C 36 QFN-EP* (6mm × 6mm)
TOP VIEW
RFMAIN
TAPMAIN
MAINBIAS
GND
GND
GND
DIVBIAS
TAPDIV
RFDIV
CC
V
36
1
2
3
4
5
6
7
8
9
10
CC
V
GND
31
MAX9981
15
GND
CC
GND
V
29
30
17
16
CC
V
GND
IFMAIN-
IFMAIN+
GND
GND
35
34
11
12
GND
GND
6mm x 6mm QFN-EP
33
13
IFDIV+
32
14
IFDIV-
GND
28
18
GND
27 LO2
26
GND
GND
25
24
GND
LOSEL
23
GND
22
V
21
GND
20
19
LO1
CC
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, VCC= +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, TA= +25°C, 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.
VCC........................................................................-0.3V to +5.5V
IFMAIN+, IFMAIN-, IFDIV+, IFDIV-,
MAINBIAS, DIVBIAS, LOSEL..................-0.3V to (VCC+ 0.3V)
TAPMAIN, TAPDIV ..............................................................+5.5V
MAINBIAS, DIVBIAS Current ................................................5mA
RFMAIN, RFDIV, LO1, LO2 Input Power ........................+20dBm
Continuous Power Dissipation (TA= +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
AC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, VCC= +4.75V to +5.25V, PLO= -5dBm to +5dBm, fRF= 825MHz to 915MHz, fLO= 725MHz to 1085MHz,
T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at VCC= +5.0V, PRF= -5dBm, PLO= 0dBm, fRF= 870MHz,
f
LO
= 770MHz, TA= +25°C, unless otherwise noted.) (Notes 1, 2)
Supply Voltage V
Supply Current I
Input High Voltage V
Input Low Voltage V
LOSEL Input Current I
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CC
CC
IH
IL
LOSEL
4.75 5.00 5.25 V
260 291 325 mA
3.5 V
0.4 V
-5 +5 µA
RF Frequency f
LO Frequency f
IF Frequency f
LO Drive Level P
Conversion Gain (Note 3) G
Gain Variation from Nominal fRF = 825MHz to 915MHz, 3σ ±0.6 dB
Conversion Loss from LO to IF
Noise Figure NF
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
RF
LO
IF
LO
Must meet RF and LO frequency range. IF
matching components affect IF frequency
range.
VCC = +5.0V,
f
= 100MHz,
IF
low-side injection,
C
P
= 0dBm,
RF
= -5dBm
P
LO
Inject P
LO port. Measure 100MHz at IF port as
P
100MHz IF,
low-side
injection
= -20dBm at fLO + 100MHz into
IN
. No RF signal at RF port.
OUT
Cellular band,
f
= 825MHz to 850MHz
RF
GSM band,
= 880MHz to 915MHz
f
RF
Cellular band,
f
= 825MHz to
RF
850MHz
GSM band,
= 880MHz
f
RF
to 915MHz
825 915 MHz
725 1085 MHz
70 170 MHz
-5 +5 dBm
2.7
dB
2.1
53 dB
10.8
dB
11.9
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, VCC= +4.75V to +5.25V, PLO= -5dBm to +5dBm, fRF= 825MHz to 915MHz, fLO= 725MHz to 1085MHz,
T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at VCC= +5.0V, PRF= -5dBm, PLO= 0dBm, fRF= 870MHz,
f
LO
= 770MHz, TA= +25°C, unless otherwise noted.) (Notes 1, 2)
Input 1dB Compression Point P
Input Third-Order Intercept Point IIP3 PLO = -5dBm to +5dBm (Notes 3, 4) 27.3 dBm
2 RF - 2 LO Spur Rejection 2 × 2
3 RF - 3 LO Spur Rejection 3 × 3
Maximum LO Leakage at RF Port
Maximum LO Leakage at IF Port
Minimum RF to IF Isolation
LO1 to LO2 Isolation
Minimum Channel Isolation
LO Switching Time 50% of LOSEL to IF settled within 2° 250 ns
RF Return Loss 25 dB
LO Return Loss
IF Return Loss
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
1dB
Low-side injection 13.6 dBm
f
= 915MHz, fLO = 815MHz,
RF
= 865MHz, PRF = -5dBm
f
SPUR
f
= 915MHz, fLO = 815MHz,
RF
= 848.3MHz, PRF = -5dBm
f
SPUR
P
= -5dBm to +5dBm,
LO
f
= 725MHz to 1100MHz
LO
P
= -5dBm to +5dBm,
LO
f
= 725MHz to 1100MHz
LO
P
= -5dBm to +5dBm,
LO
f
= 825MHz to 915MHz
RF
f
= 825MHz to 915MHz, P
RF
+5dBm, f
= 825MHz
f
RF
to 915MHz,
f
LO
to 1085MHz
LO port selected 19
LO port unselected 14.3
RF and LO terminated into 50Ω,
= 100MHz (Note 6)
f
IF
= 100MHz (Note 5)
IF
= 725MHz
P
RFMAIN
terminated with 50Ω.
Measured power at IFDIV
relative to IFMAIN.
P
= -5dBm, RFMAIN
RFDIV
terminated with 50Ω.
Measured power at
IFMAIN relative to IFDIV.
Main 53.3
Diversity 43.2
= P
LO2
=
LO1
= -5dBm, RFDIV
dBc
79.7 dBc
-42 dBm
-30.6 dBm
18 dB
52 dB
39.5
dBc
42
dB
15 dB
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
4 _______________________________________________________________________________________
Typical Operating Characteristics
(Typical Application Circuit, VCC= 5.0V, PRF= -5dBm, PLO= 0dBm, TA= +25°C, unless otherwise noted.)
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc01
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900880860840
1
2
3
4
5
0
820 920
fIF = 100MHz
MAIN MIXER
TA = -40°C
TA = +85°C
TA = +25°C
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc02
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900880860840
1
2
3
4
5
0
820 920
fIF = 100MHz
MAIN MIXER
PLO = -5dBm, 0dBm, +5dBm
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc03
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900880860840
1
2
3
4
5
0
820 920
fIF = 100MHz
MAIN MIXER
VCC = 4.75V, 5.0V, 5.25V
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc04
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900880860840
1
2
3
4
5
0
820 920
fIF = 120MHz
MAIN MIXER
TA = -40°C
TA = +85°C
TA = +25°C
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc05
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900880860840
1
2
3
4
5
0
820 920
fIF = 120MHz
MAIN MIXER
PLO = -5dBm, 0dBm, +5dBm
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc06
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900880860840
1
2
3
4
5
0
820 920
fIF = 120MHz
MAIN MIXER
VCC = 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)
900880860840
50
55
60
65
70
75
80
45
820 920
fIF = 100MHz
MAIN MIXER
P
RF
= -5dBm
TA = +85°C
TA = +25°C
TA = -40°C
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc08
RF FREQUENCY (MHz)
2 RF - 2 LO RESPONSE (dBc)
900880860840
55
65
75
85
45
820 920
PLO = -5dBm
PLO = 0dBm
PLO = +5dBm
fIF = 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)
900880860840
50
55
60
65
70
75
80
45
820 920
fIF = 100MHz
MAIN MIXER
P
RF
= -5dBm
VCC = 4.75V, 5.0V, 5.25V
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
_______________________________________________________________________________________ 5
Typical Operating Characteristics (continued)
(Typical Application Circuit, VCC= 5.0V, PRF= -5dBm, PLO= 0dBm, TA= +25°C, unless otherwise noted.)
vs. RF FREQUENCY LOW-SIDE INJECTION
2 RF - 2 LO RESPONSE
60
TA = +85°C
55
50
45
2 RF - 2 LO RESPONSE (dBc)
40
820 920
TA = +25°C
RF FREQUENCY (MHz)
fIF = 100MHz
DIVERSITY MIXER
P
RF
TA = -40°C
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
70
65
60
55
2 LO - 2 RF RESPONSE (dBc)
50
45
820 920
RF FREQUENCY (MHz)
TA = +85°C
TA = +25°C
TA = -40°C
= -5dBm
900880860840
fIF = 120MHz
MAIN MIXER
= -5dBm
P
RF
900880860840
60
MAX9981 toc10
55
50
45
2 RF - 2 LO RESPONSE (dBc)
40
60
MAX9981 toc13
58
56
54
2 LO - 2 RF RESPONSE (dBc)
52
50
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
fIF = 100MHz
PLO = -5dBm
DIVERSITY MIXER
= -5dBm
P
RF
900880860840
PLO = +5dBm
PLO = 0dBm
820 920
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
fIF = 120MHz
MAIN MIXER
= -5dBm
P
RF
PLO = 0dBm
PLO = -5dBm
PLO = +5dBm
820 920
RF FREQUENCY (MHz)
900880860840
vs. RF FREQUENCY LOW-SIDE INJECTION
60
MAX9981 toc11
55
50
45
2 RF - 2 LO RESPONSE (dBc)
40
820 920
vs. RF FREQUENCY HIGH-SIDE INJECTION
60
MAX9981 toc14
58
56
54
2 LO - 2 RF RESPONSE (dBc)
52
50
820 920
VCC = 4.75V, 5.0V, 5.25V
2 RF - 2 LO RESPONSE
fIF = 100MHz
DIVERSITY MIXER
= -5dBm
P
RF
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE
fIF = 120MHz
MAIN MIXER
P
VCC = 5.25V
VCC = 4.75, 5.0V
RF FREQUENCY (MHz)
900880860840
= -5dBm
RF
900880860840
MAX9981 toc12
MAX9981 toc15
vs. RF FREQUENCY HIGH-SIDE INJECTION
2 LO - 2 RF RESPONSE
47
46
45
TA = +85°C
44
43
42
2 LO - 2 RF RESPONSE (dBc)
41
40
TA = +25°C
TA = -40°C
820 920
RF FREQUENCY (MHz)
fIF = 120MHz
DIVERSITY MIXER
P
RF
= -5dBm
900880860840
vs. RF FREQUENCY HIGH-SIDE INJECTION
52.5
50.0
MAX9981 toc16
47.5
45.0
42.5
2 LO - 2 RF RESPONSE (dBc)
40.0
37.5
820 920
2 LO - 2 RF RESPONSE
PLO = 0dBm
PLO = +5dBm
RF FREQUENCY (MHz)
fIF = 120MHz
DIVERSITY MIXER
= -5dBm
P
RF
PLO = -5dBm
900880860840
vs. RF FREQUENCY HIGH-SIDE INJECTION
46
MAX9981 toc17
45
44
43
2 LO - 2 RF RESPONSE (dBc)
42
820 920
2 LO - 2 RF RESPONSE
VCC = 5.25V
VCC = 4.75V, 5.0V
RF FREQUENCY (MHz)
fIF = 120MHz
DIVERSITY MIXER
= -5dBm
P
RF
900880860840
MAX9981 toc18