MAXIM MAX9981

19-2588; Rev 0; 9/02
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
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.
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
Ordering Information
Applications
GSM850/GSM900 2G and 2.5G EDGE BaseStation Receivers
Cellular cdmaOne™ and cdma2000™ BaseStation Receivers
PART
TEMP RANGE
MAX9981EGX-T
*EP = Exposed paddle.
Pin Configuration/
Functional Diagram
GND
GND
IFMAIN+
IFMAIN-
GND
VCC
GND
GND
35
34
33
32
31
30
29
28
1
TAPMAIN
2
MAINBIAS
3
25 GND
GND
4
24 GND
GND
5
23 LOSEL
GND
6
22 GND
DIVBIAS
7
21 VCC
TAPDIV
8
20 GND
RFDIV
9
19 LO1
27 LO2
13
14
15
16
17
18
IFDIV+
IFDIV-
GND
VCC
GND
GND
11
GND
26 GND
12
10
MAX9981
GND
iDEN is a trademark of Motorola, Inc.
RFMAIN
VCC
cdma2000 is a trademark of Telecommunications Industry
Association.
VCC
TOP VIEW
Microwave Point-to-Point Links
cdmaOne is a trademark of CDMA Development Group.
36
TDMA and Integrated Digital Enhanced Network
(iDEN)™ Base-Station Receivers
Digital and Spread-Spectrum Communication
Systems
PIN-PACKAGE
-40°C to +85°C 36 QFN-EP* (6mm × 6mm)
6mm x 6mm QFN-EP
________________________________________________________________ Maxim Integrated Products
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.
1
MAX9981
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.
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
ABSOLUTE MAXIMUM RATINGS
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
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, 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, TA = -40°C to +85°C, unless otherwise noted. Typical values are at
VCC = +5.0V, TA = +25°C, unless otherwise noted.)
PARAMETER
MIN
TYP
MAX
UNITS
VCC
4.75
5.00
5.25
V
Supply Current
ICC
260
291
325
mA
Input High Voltage
VIH
3.5
Input Low Voltage
VIL
0.4
V
+5
µA
Supply Voltage
LOSEL Input Current
SYMBOL
CONDITIONS
ILOSEL
V
-5
AC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, VCC = +4.75V to +5.25V, PLO = -5dBm to +5dBm, fRF = 825MHz to 915MHz, fLO = 725MHz to 1085MHz,
TA = -40°C to +85°C, unless otherwise noted. Typical values are at VCC = +5.0V, PRF = -5dBm, PLO = 0dBm, fRF = 870MHz,
fLO = 770MHz, TA = +25°C, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RF Frequency
fRF
825
915
MHz
LO Frequency
fLO
725
1085
MHz
70
170
MHz
-5
+5
dBm
IF Frequency
LO Drive Level
Conversion Gain (Note 3)
fIF
Must meet RF and LO frequency range. IF
matching components affect IF frequency
range.
PLO
GC
VCC = +5.0V,
fIF = 100MHz,
low-side injection,
PRF = 0dBm,
PLO = -5dBm
Cellular band,
fRF = 825MHz to
850MHz
2.7
GSM band,
fRF = 880MHz
to 915MHz
2.1
Gain Variation from Nominal
fRF = 825MHz to 915MHz, 3σ
Conversion Loss from LO to IF
Inject PIN = -20dBm at fLO + 100MHz into
LO port. Measure 100MHz at IF port as
POUT. No RF signal at RF port.
Noise Figure
100MHz IF,
low-side
injection
2
NF
dB
±0.6
dB
53
dB
Cellular band,
fRF = 825MHz to 850MHz
10.8
GSM band,
fRF = 880MHz to 915MHz
11.9
dB
_______________________________________________________________________________________
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
(Typical Application Circuit, VCC = +4.75V to +5.25V, PLO = -5dBm to +5dBm, fRF = 825MHz to 915MHz, fLO = 725MHz to 1085MHz,
TA = -40°C to +85°C, unless otherwise noted. Typical values are at VCC = +5.0V, PRF = -5dBm, PLO = 0dBm, fRF = 870MHz,
fLO = 770MHz, TA = +25°C, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Input 1dB Compression Point
P1dB
Low-side injection
Input Third-Order Intercept Point
IIP3
PLO = -5dBm to +5dBm (Notes 3, 4)
2 RF - 2 LO Spur Rejection
2×2
fRF = 915MHz, fLO = 815MHz,
fSPUR = 865MHz, PRF = -5dBm
3 RF - 3 LO Spur Rejection
3×3
fRF = 915MHz, fLO = 815MHz,
fSPUR = 848.3MHz, PRF = -5dBm
79.7
dBc
Maximum LO Leakage at RF Port
PLO = -5dBm to +5dBm,
fLO = 725MHz to 1100MHz
-42
dBm
Maximum LO Leakage at IF Port
PLO = -5dBm to +5dBm,
fLO = 725MHz to 1100MHz
-30.6
dBm
Minimum RF to IF Isolation
PLO = -5dBm to +5dBm,
fRF = 825MHz to 915MHz
18
dB
LO1 to LO2 Isolation
fRF = 825MHz to 915MHz, PLO1 = PLO2 =
+5dBm, fIF = 100MHz (Note 5)
52
dB
Minimum Channel Isolation
LO Switching Time
fRF = 825MHz
to 915MHz,
fLO = 725MHz
to 1085MHz
IF Return Loss
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
dBm
27.3
dBm
Main
53.3
Diversity
43.2
PRFMAIN = -5dBm, RFDIV
terminated with 50Ω.
Measured power at IFDIV
relative to IFMAIN.
dBc
39.5
dBc
PRFDIV = -5dBm, RFMAIN
terminated with 50Ω.
Measured power at
IFMAIN relative to IFDIV.
50% of LOSEL to IF settled within 2°
RF Return Loss
LO Return Loss
13.6
LO port selected
LO port unselected
RF and LO terminated into 50Ω,
fIF = 100MHz (Note 6)
42
250
ns
25
dB
19
14.3
15
dB
dB
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. fLO1 and fLO2 are offset by 1MHz.
IF return loss can be optimized by external matching components.
_______________________________________________________________________________________
3
MAX9981
AC ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(Typical Application Circuit, VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, TA = +25°C, unless otherwise noted.)
2
TA = +85°C
1
5
3
2
PLO = -5dBm, 0dBm, +5dBm
MAX9981 toc03
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
fIF = 100MHz
MAIN MIXER
4
CONVERSION GAIN (dB)
3
fIF = 100MHz
MAIN MIXER
4
CONVERSION GAIN (dB)
4
CONVERSION GAIN (dB)
fIF = 100MHz
MAIN MIXER
TA = -40°C
5
MAX9981 toc01
5
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc02
CONVERSION GAIN
vs. RF FREQUENCY LOW-SIDE INJECTION
1
3
2
VCC = 4.75V, 5.0V, 5.25V
1
TA = +25°C
0
0
820
840
860
880
920
0
820
860
880
900
920
820
840
860
880
900
920
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
CONVERSION GAIN
vs. RF FREQUENCY HIGH-SIDE INJECTION
2
MAX9981 toc05
5
3
2
PLO = -5dBm, 0dBm, +5dBm
1
860
2
VCC = 4.75V, 5.0V, 5.25V
1
0
840
3
TA = +25°C
0
820
fIF = 120MHz
MAIN MIXER
4
CONVERSION GAIN (dB)
3
fIF = 120MHz
MAIN MIXER
4
CONVERSION GAIN (dB)
TA = -40°C
TA = +85°C
5
MAX9981 toc04
fIF = 120MHz
MAIN MIXER
MAX9981 toc06
RF FREQUENCY (MHz)
1
880
900
920
0
820
840
860
880
900
920
820
840
860
880
900
920
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
70
65
TA = +25°C
60
55
TA = -40°C
85
fIF = 100MHz
MAIN MIXER
PRF = -5dBm
PLO = -5dBm
75
65
PLO = 0dBm
55
50
840
860
880
RF FREQUENCY (MHz)
900
920
70
65
60
55
VCC = 4.75V, 5.0V, 5.25V
45
45
820
fIF = 100MHz
MAIN MIXER
PRF = -5dBm
75
50
PLO = +5dBm
45
80
2 RF - 2 LO RESPONSE (dBc)
75
fIF = 100MHz
MAIN MIXER
PRF = -5dBm
2 RF - 2 LO RESPONSE (dBc)
TA = +85°C
MAX9981 toc09
RF FREQUENCY (MHz)
MAX9981 toc08
RF FREQUENCY (MHz)
MAX9981 toc07
RF FREQUENCY (MHz)
80
4
840
RF FREQUENCY (MHz)
4
CONVERSION GAIN (dB)
900
RF FREQUENCY (MHz)
5
2 RF - 2 LO RESPONSE (dBc)
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
820
840
860
880
RF FREQUENCY (MHz)
900
920
820
840
860
880
RF FREQUENCY (MHz)
_______________________________________________________________________________________
900
920
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
50
TA = +25°C
45
55
50
PLO = 0dBm
45
40
820
840
860
880
fIF = 100MHz
DIVERSITY MIXER
PRF = -5dBm
MAX9981 toc12
60
55
50
VCC = 4.75V, 5.0V, 5.25V
45
PLO = -5dBm
TA = -40°C
900
920
40
820
840
860
880
900
920
820
840
860
880
900
920
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
TA = +85°C
60
55
TA = +25°C
50
58
PLO = 0dBm
56
PLO = -5dBm
54
60
TA = -40°C
860
880
900
56
VCC = 5.25V
54
VCC = 4.75, 5.0V
50
50
840
58
PLO = +5dBm
45
820
fIF = 120MHz
MAIN MIXER
PRF = -5dBm
52
52
MAX9981 toc15
fIF = 120MHz
MAIN MIXER
PRF = -5dBm
2 LO - 2 RF RESPONSE (dBc)
65
60
MAX9981 toc14
fIF = 120MHz
MAIN MIXER
PRF = -5dBm
2 LO - 2 RF RESPONSE (dBc)
MAX9981 toc13
70
920
820
840
860
880
900
820
920
840
860
880
900
920
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
2 LO - 2 RF RESPONSE
vs. RF FREQUENCY HIGH-SIDE INJECTION
fIF = 120MHz
DIVERSITY MIXER
PRF = -5dBm
46
45
TA = +85°C
44
TA = +25°C
43
42
TA = -40°C
52.5
2 LO - 2 RF RESPONSE (dBc)
47
50.0
fIF = 120MHz
DIVERSITY MIXER
PRF = -5dBm
PLO = 0dBm
PLO = +5dBm
47.5
45.0
42.5
46
fIF = 120MHz
DIVERSITY MIXER
PRF = -5dBm
45
44
VCC = 5.25V
43
40.0
41
MAX9981 toc18
RF FREQUENCY (MHz)
MAX9981 toc16
RF FREQUENCY (MHz)
2 LO - 2 RF RESPONSE (dBc)
2 LO - 2 RF RESPONSE (dBc)
MAX9981 toc11
PLO = +5dBm
40
2 LO - 2 RF RESPONSE (dBc)
fIF = 100MHz
DIVERSITY MIXER
PRF = -5dBm
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
2 RF - 2 LO RESPONSE (dBc)
55
60
MAX9981 toc17
2 RF - 2 LO RESPONSE (dBc)
TA = +85°C
fIF = 100MHz
DIVERSITY MIXER
PRF = -5dBm
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
2 RF - 2 LO RESPONSE (dBc)
60
MAX9981 toc10
2 RF - 2 LO RESPONSE
vs. RF FREQUENCY LOW-SIDE INJECTION
VCC = 4.75V, 5.0V
PLO = -5dBm
40
37.5
820
840
860
880
RF FREQUENCY (MHz)
900
920
42
820
840
860
880
RF FREQUENCY (MHz)
900
920
820
840
860
880
900
920
RF FREQUENCY (MHz)
_______________________________________________________________________________________
5
MAX9981
Typical Operating Characteristics (continued)
(Typical Application Circuit, VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(Typical Application Circuit, VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, TA = +25°C, unless otherwise noted.)
29
INPUT IP3 (dBm)
27
27
26
25
860
27
VCC = 5.0V
26
PLO = -5dBm
25
840
28
PLO = 0dBm
TA = +25°C
820
fIF = 100MHz
MAIN MIXER
VCC = 5.25V
28
TA = -40°C
880
920
900
VCC = 4.75V
25
820
840
860
880
900
920
820
840
860
880
900
920
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
INPUT IP3
vs. RF FREQUENCY HIGH-SIDE INJECTION
INPUT IP3
vs. RF FREQUENCY HIGH-SIDE INJECTION
INPUT IP3
vs. RF FREQUENCY HIGH-SIDE INJECTION
TA = -40°C
fIF = 120MHz
MAIN MIXER
29
30
MAX9981 toc23
29
30
MAX9981 toc22
fIF = 120MHz
MAIN MIXER
fIF = 120MHz
MAIN MIXER
VCC = 5.25V
29
28
27
INPUT IP3 (dBm)
INPUT IP3 (dBm)
PLO = -5dBm
28
27
PLO = 0dBm
MAX9981 toc24
RF FREQUENCY (MHz)
30
INPUT IP3 (dBm)
30
PLO = +5dBm
28
26
fIF = 100MHz
MAIN MIXER
29
TA = +85°C
INPUT IP3 (dBm)
INPUT IP3 (dBm)
29
30
INPUT IP3
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc21
fIF = 100MHz
MAIN MIXER
MAX9981 toc19
30
INPUT IP3
vs. RF FREQUENCY LOW-SIDE INJECTION
MAX9981 toc20
INPUT IP3
vs. RF FREQUENCY LOW-SIDE INJECTION
VCC = 5.0V
28
27
TA = +25°C
26
26
26
PLO = +5dBm
TA = +85°C
25
840
860
880
900
920
25
820
840
860
880
900
920
820
840
860
880
900
920
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
INPUT P1dB
vs. RF FREQUENCY LOW-SIDE INJECTION
INPUT P1dB
vs. RF FREQUENCY LOW-SIDE INJECTION
INPUT P1dB
vs. RF FREQUENCY LOW-SIDE INJECTION
TA = +85°C
TA = +25°C
14
13
15
MAX9981 toc26
PLO = -5dBm
PLO = 0dBm
14
13
860
880
15
VCC = 5.25V
VCC = 5.0V
14
VCC = 4.75V
12
RF FREQUENCY (MHz)
16
PLO = +5dBm
12
840
fIF = 100MHz
MAIN MIXER
13
TA = -40°C
820
17
INPUT P1dB (dBm)
15
fIF = 100MHz
MAIN MIXER
16
INPUT P1dB (dBm)
16
17
MAX9981 toc25
fIF = 100MHz
MAIN MIXER
900
920
MAX9981 toc27
RF FREQUENCY (MHz)
17
6
VCC = 4.75V
25
820
INPUT P1dB (dBm)
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
12
820
840
860
880
RF FREQUENCY (MHz)
900
920
820
840
860
880
RF FREQUENCY (MHz)
_______________________________________________________________________________________
900
920
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
15
14
fIF = 120MHz
MAIN MIXER
16
13
17
16
PLO = -5dBm
VCC = 5.25V
15
14
PLO = 0dBm
13
fIF = 120MHz
MAIN MIXER
MAX9981 toc30
TA = +85°C
TA = +25°C
INPUT P1dB (dBm)
INPUT P1dB (dBm)
16
17
INPUT P1dB (dBm)
fIF = 120MHz
MAIN MIXER
MAX9981 toc28
17
INPUT P1dB
vs. RF FREQUENCY HIGH-SIDE INJECTION
INPUT P1dB
vs. RF FREQUENCY HIGH-SIDE INJECTION
MAX9981 toc29
INPUT P1dB
vs. RF FREQUENCY HIGH-SIDE INJECTION
PLO = +5dBm
VCC = 5.0V
15
14
VCC = 4.75V
13
TA = -40°C
12
840
860
880
920
900
820
840
860
880
900
820
920
840
860
880
900
920
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
CHANNEL ISOLATION
vs. RF FREQUENCY LOW-SIDE INJECTION
CHANNEL ISOLATION
vs. RF FREQUENCY LOW-SIDE INJECTION
CHANNEL ISOLATION
vs. RF FREQUENCY LOW-SIDE INJECTION
TA = +85°C
45
40
TA = +25°C
55
MAX9981 toc32
RF MAIN IN/IF DIVERSITY OUT
fIF = 100MHz
CHANNEL ISOLATION (dBc)
CHANNEL ISOLATION (dBc)
50
55
MAX9981 toc31
RF MAIN IN/IF DIVERSITY OUT
fIF = 100MHz
50
45
40
RF DIVERSITY IN/IF MAIN OUT
fIF = 100MHz
MAX9981 toc33
RF FREQUENCY (MHz)
55
CHANNEL ISOLATION (dBc)
12
12
820
50
45
40
PLO = -5dBm, 0dBm, +5dBm
PLO = -5dBm, 0dBm, +5dBm
TA = -40°C
35
35
820
840
880
900
920
35
820
840
860
880
900
920
820
840
860
880
900
920
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
CHANNEL ISOLATION
vs. RF FREQUENCY HIGH-SIDE INJECTION
CHANNEL ISOLATION
vs. RF FREQUENCY HIGH-SIDE INJECTION
CHANNEL ISOLATION
vs. RF FREQUENCY HIGH-SIDE INJECTION
TA = +85°C
45
TA = +25°C
40
55
MAX9981 toc35
RF MAIN IN/IF DIVERSITY OUT
fIF = 120MHz
CHANNEL ISOLATION (dBc)
CHANNEL ISOLATION (dBc)
50
55
MAX9981 toc34
RF MAIN IN/IF DIVERSITY OUT
fIF = 120MHz
50
45
40
RF DIVERSITY IN/IF MAIN OUT
fIF = 120MHz
MAX9981 toc36
RF FREQUENCY (MHz)
55
CHANNEL ISOLATION (dBc)
860
50
45
40
PLO = -5dBm, 0dBm, +5dBm
PLO = -5dBm, 0dBm, +5dBm
TA = -40°C
35
35
820
840
860
880
RF FREQUENCY (MHz)
900
920
35
820
840
860
880
RF FREQUENCY (MHz)
900
920
820
840
860
880
900
920
RF FREQUENCY (MHz)
_______________________________________________________________________________________
7
MAX9981
Typical Operating Characteristics (continued)
(Typical Application Circuit, VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(Typical Application Circuit, VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, TA = +25°C, unless otherwise noted.)
54
53
TA = +25°C
TA = +-40°C
52
55
LO OFFSET 1MHz
fIF = 100MHz
DIVERSITY MIXER
PLO = -5dBm
54
53
PLO = 0dBm
52
LO SWITCH ISOLATION
vs. RF FREQUENCY HIGH-SIDE INJECTION
56
MAX9981 toc39
TA = +85°C
56
MAX9981 toc38
LO OFFSET 1MHz
fIF = 100MHz
DIVERSITY MIXER
LO SWITCH ISOLATION (dBc)
55
MAX9981 toc37
LO SWITCH ISOLATION (dBc)
56
LO SWITCH ISOLATION
vs. RF FREQUENCY LOW-SIDE INJECTION
LO SWITCH ISOLATION (dBc)
LO SWITCH ISOLATION
vs. RF FREQUENCY LOW-SIDE INJECTION
LO OFFSET 1MHz
fIF = 120MHz
MAIN MIXER
55
TA = +85°C
54
53
52
PLO = +5dBm
TA = -40°C
TA = +25°C
51
51
840
860
880
920
900
820
840
860
880
920
900
820
840
860
880
RF FREQUENCY (MHz)
LO LEAKAGE AT IF PORT
vs. LO FREQUENCY
LO LEAKAGE AT IF PORT
vs. LO FREQUENCY
LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
TA = +25°C
-36
-39
PLO = 0dBm
PLO = +5dBm
-33
MAIN MIXER
-36
PLO = -5dBm
-45
-50
-55
-60
PLO = 0dBm
-65
PLO = +5dBm
TA = -40°C
-42
-39
PLO = -5dBm
-45
-42
800
850
900
950
1000
800
850
900
950
1000
700
1100
RF TO IF ISOLATION
vs. RF FREQUENCY
NOISE FIGURE
vs. RF FREQUENCY LOW-SIDE INJECTION
18
TA = -40°C
15
MAX9981 toc44
PLO = 0dBm, +5dBm
22
880
RF FREQUENCY (MHz)
900
920
fIF = 100MHz
MAIN MIXER
14
24
13
TA = +85°C
12
11
10
20
TA = +25°C
9
18
860
15
NOISE FIGURE (dB)
TA = +25°C
MAIN MIXER
RF TO IF ISOLATION (dB)
TA = +85°C
21
26
MAX9981 toc45
RF TO IF ISOLATION
vs. RF FREQUENCY
PLO = -5dBm
8
1000
LO FREQUENCY (MHz)
27
840
900
LO FREQUENCY (MHz)
MAIN MIXER
820
800
LO FREQUENCY (MHz)
30
24
-70
750
MAX9981 toc43
750
MAX9981 toc42
-30
-40
LO LEAKAGE (dBm)
-33
MAIN MIXER
LO LEAKAGE (dBm)
TA = +85°C
-27
MAX9981 toc41
MAIN MIXER
920
900
RF FREQUENCY (MHz)
-30
LO LEAKAGE (dBm)
51
RF FREQUENCY (MHz)
MAX9981 toc40
820
RF TO IF ISOLATION (dB)
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
TA = -40°C
8
820
840
860
880
RF FREQUENCY (MHz)
900
920
820
840
860
880
RF FREQUENCY (MHz)
_______________________________________________________________________________________
900
920
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
15
20
25
LO RETURN LOSS vs. LO FREQUENCY
MAX9981 toc47
0
MAIN MIXER
SET BY EXTERNAL MATCHING
5
LO INPUT SELECTED
5
LO RETURN LOSS (dB)
IF RETURN LOSS (dB)
PLO = -5dBm, 0dBm, +5dBm
10
15
10
PLO = -5dBm
15
20
25
PLO = 0dBm
30
30
PLO = +5dBm
35
20
800
900
1000
1100
50
75
RF FREQUENCY (MHz)
100
125
150
200
175
800
1000
1100
SUPPLY CURRENT vs. TEMPERATURE
320
310
SUPPLY CURRENT (mA)
LO INPUT UNSELECTED
5
900
LO FREQUENCY (MHz)
LO RETURN LOSS vs. LO FREQUENCY
0
10
15
20
PLO = -5dBm, 0dBm, +5dBm
25
700
IF FREQUENCY (MHz)
MAX9981 toc49
700
VCC = 5.25V
300
VCC = 5.0V
290
280
270
30
35
MAX9981 toc50
35
LO RETURN LOSS (dB)
RF RETURN LOSS (dB)
5
10
IF RETURN LOSS vs. IF FREQUENCY
0
MAX9981 toc46
MAIN MIXER
MAX9981 toc48
RF RETURN LOSS vs. RF FREQUENCY
0
VCC = 4.75V
260
700
800
900
1000
LO FREQUENCY (MHz)
1100
-40
-15
10
35
60
85
TEMPERATURE (°C)
_______________________________________________________________________________________
9
MAX9981
Typical Operating Characteristics (continued)
(Typical Application Circuit, VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, TA = +25°C, unless otherwise noted.)
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
MAX9981
Pin Description
PIN
NAME
FUNCTION
Main Channel RF Input. This input is internally matched to 50Ω and is DC shorted to ground
through a balun.
1
RFMAIN
2
TAPMAIN
Main RF Balun Center Tap. Connect bypass capacitors from this pin to ground.
3
MAINBIAS
Bias control for the Main Mixer. Connect a 267Ω resistor from this pin to ground to set the bias
current for the main mixer.
4, 5, 6, 11,
12, 15, 17,
18, 20, 22,
24, 25, 26,
28, 29, 31,
34, 35, EP
GND
7
DIVBIAS
Bias Control for the Diversity Mixer. Connect a 267Ω resistor from this pin to ground to set the bias
current for the diversity mixer.
8
TAPDIV
Diversity RF Balun Center Tap. Connect bypass capacitors from this pin to ground.
9
RFDIV
10, 16, 21,
30, 36
VCC
13, 14
IFDIV+, IFDIV-
19
LO1
23
LOSEL
27
LO2
32, 33
IFMAIN-,
IFMAIN+
10
Ground
Diversity Channel RF Input. This input is internally matched to 50Ω and is DC shorted to ground
through a balun.
Power-Supply Connections. Connect bypass capacitors as shown in the Typical Application
Circuit.
Differential IF Output for Diversity Mixer. Connect 560nH pullup inductors and 137Ω pullup
resistors from each of these pins to VCC for a 70MHz to 100MHz IF range.
Local Oscillator Input 1. This input is internally matched to 50Ω and is DC shorted to ground
through a balun.
Local Oscillator Select. Set this pin to logic HIGH to select LO1; set to logic LOW to select LO2.
Local Oscillator Input 2. This input is internally matched to 50Ω and is DC shorted to ground
through a balun.
Differential IF Output for the Main Mixer. Connect 560nH pullup inductors and 137Ω pullup
resistors from each of these pins to VCC for a 70MHz to 100MHz IF range.
______________________________________________________________________________________
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
C14
L1
3
R3
T1
6
IFMAIN_OUT
5.0V
2
C13
4:1 (200:50)
TRANSFORMER
C16
L2
4
1
R4
C15
5.0V
5.0V
C5
C1
RFMAIN
RF_MAIN
TAPMAIN
C11
C2
R1
MAINBIAS
GND
GND
R2
GND
DIVBIAS
C12
C3
TAPDIV
RFDIV
RF_DIV
GND
28
GND
29
30
31
VCC
GND
IFMAIN32
IFMAIN+
33
GND
34
GND
35
36
VCC
C10
C8
1
27
MAX9981
2
26
3
25
4
24
5
23
6
22
7
21
8
20
9
19
LO2
LO2
GND
GND
GND
LOSEL
LO SELECT
GND
5.0V
VCC
GND
LO1
LO1
C7
18
GND
GND
17
16
VCC
GND
15
14
IFDIV-
13
IFDIV+
11
12
GND
5.0V
GND
VCC
10
C4
5.0V
C6
C9
C19
L4
3
R6
T2
6
IFDIV_OUT
5.0V
C17
C20
L3
R5
2
4:1 (200:50)
TRANSFORMER
1
4
C18
______________________________________________________________________________________
11
MAX9981
Typical Application Circuit
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
MAX9981
Component List
COMPONENT
VALUE
SIZE
C1, C4
33pF
0603
C2, C3
3.9pF
0603
Murata GRM1885C1H3R9C
C5, C6, C9, C10
100pF
0603
Murata GRM1885C1H101J
C7, C8
15pF
0603
Murata GRM1885C1H150J
C11, C12
0.033µF
0603
Murata GRM188R71E333K
C13, C16, C17, C20
220pF
0603
Murata GRM1885C1H221J
C14, C15, C18, C19
330pF
0603
Murata GRM1885C1H331J
L1–L4
560nH
1008
CoilCraft 1008CS-561XJBB
R1, R2
267Ω ±1%
0603
—
R3–R6
137Ω ±1%
0603
—
T1, T2
4:1 (200:50)
—
Detailed Description
The MAX9981 downconverter mixers are designed for
GSM and CDMA base-station receivers with an RF frequency between 825MHz and 915MHz. Each active
mixer provides 2.1dB to 2.7dB of overall conversion
gain to the receive signal, removing the need for an
external IF amplifier. The mixers have excellent input
IP3 measuring greater than +27dBm. The device also
features integrated RF and LO baluns that allow the
mixers to be driven with single-ended signals.
RF Inputs
The MAX9981 has two RF inputs (RFMAIN, RFDIV) that are
internally matched to 50Ω requiring no external matching
components. A 33pF DC-blocking capacitor is required at
the input since the input is internally DC shorted to ground
through a balun. Return loss is better than 15dB over the
entire frequency range of 825MHz to 915MHz.
LO Inputs
The mixers can be used for either high-side or low-side
injection applications with an LO frequency range of
725MHz to 1085MHz. An internal LO switch allows for
switching between two single-ended LO ports. This is
useful for fast frequency changes/frequency hopping. LO
switching time is less than 250ns. The switch is controlled
by a digital input (LOSEL) that when high, selects LO1
and when low, selects LO2. The selected LO input mixes
with both RFMAIN and RFDIV to produce the IF signals.
Internal LO buffers allow for a wide power range on the
LO ports. The LO signal power can vary from -5dBm to
+5dBm. LO1 and LO2 are internally matched to 50Ω, so
only a 15pF DC-blocking capacitor is required at each
LO port.
12
PART NUMBER
Murata GRM1885C1H330J
Mini-Circuits TC4-1W-7A
IF Outputs
Each mixer has an IF frequency range of 70MHz to
170MHz. The differential IF output ports require external pullup inductors to VCC to resonate out the differential on-chip capacitance of 1.8pF. See the Typical
Application Circuit for recommended component values for an IF of 70MHz to 100MHz. The IF match can
be optimized for higher IF frequencies by reducing the
values of the pullup inductors L1, L2, L3, and L4. Note:
Removing the ground plane from underneath these
inductors reduces parasitic capacitive loading and
improves VSWR.
Bias Circuitry
Connect bias resistors from MAINBIAS and DIVBIAS to
ground to set the mixer bias current. A nominal resistor
value of 267Ω sets an input IP3 of +27dBm and supply
current of 290mA. Bias currents are fine-tuned at the
factory and should not be adjusted.
Applications Information
Layout Considerations
A properly designed PC board is an essential part of
any RF/microwave circuit. Keep RF signal lines as short
as possible to reduce losses, radiation, and inductance. For best performance, route the ground pin
traces directly to the exposed paddle underneath the
package. This paddle should be connected to the
ground plane of the board by using multiple vias under
the device to provide the best RF/thermal conduction
path. Solder the exposed paddle, on the bottom of the
device package, to a PC board exposed pad.
______________________________________________________________________________________
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
Chip Information
TRANSISTOR COUNT: 358
PROCESS: BiCMOS
______________________________________________________________________________________
13
MAX9981
Power Supply Bypassing
Proper voltage supply bypassing is essential for high-frequency circuit stability. Bypass each VCC pin, TAPMAIN,
and TAPDIV with the capacitors shown in the typical
application circuit. Place the TAPMAIN and TAPDIV
bypass capacitors to ground within 100mils of the
TAPMAIN and TAPDIV pins.
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
36L,40L, QFN.EPS
MAX9981
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
14
______________________________________________________________________________________
825MHz to 915MHz, Dual SiGe High-Linearity
Active Mixer
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15
© 2002 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX9981
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)