General Description
The MAX19985A high-linearity, dual-channel, downcon-
version mixer is designed to provide approximately
8.7dB gain, +25.5dBm of IIP3, and 9.0dB of noise fig-
ure for 700MHz to 1000MHz diversity receiver applica-
tions. With an optimized LO frequency range of
900MHz to 1300MHz, this mixer is ideal for high-side
LO injection architectures in the cellular and new
700MHz bands. Low-side LO injection is supported by
the MAX19985, which is pin-pin and functionally com-
patible with the MAX19985A.
In addition to offering excellent linearity and noise per-
formance, the MAX19985A also yields a high level
of component integration. This device includes two
double-balanced passive mixer cores, two LO buffers,
a dual-input LO selectable switch, and a pair of differ-
ential IF output amplifiers. On-chip baluns are also inte-
grated to allow for single-ended RF and LO inputs.
The MAX19985A requires a nominal LO drive of 0dBm
and a typical supply current of 330mA at VCC = +5.0V
or 280mA at VCC = +3.3V.
The MAX19985/MAX19985A are pin compatible with
the MAX19995/MAX19995A series of 1700MHz to
2200MHz mixers and pin similar with the MAX19997A/
MAX19999 series of 1850MHz to 3800MHz mixers,
making this entire family of downconverters ideal for
applications where a common PCB layout is used
across multiple frequency bands.
The MAX19985A is available in a 6mm x 6mm, 36-pin
thin QFN package with an exposed pad. Electrical per-
formance is guaranteed over the extended temperature
range of TC= -40°C to +85°C.
Applications
850MHz WCDMA and cdma2000®Base Stations
700MHz LTE/WiMAX™ Base Stations
GSM850/900 2G and 2.5G EDGE Base Stations
iDEN®Base Stations
Fixed Broadband Wireless Access
Wireless Local Loop
Private Mobile Radios
Military Systems
Features
o700MHz to 1000MHz RF Frequency Range
o900MHz to 1300MHz LO Frequency Range
o50MHz to 500MHz IF Frequency Range
o8.7dB Typical Conversion Gain
o9.0dB Typical Noise Figure
o+25.5dBm Typical Input IP3
o+12.6dBm Typical Input 1dB Compression Point
o76dBc Typical 2LO-2RF Spurious Rejection at
PRF = -10dBm
oDual Channels Ideal for Diversity Receiver
Applications
o48dB Typical Channel-to-Channel Isolation
oLow -3dBm to +3dBm LO Drive
oIntegrated LO Buffer
oInternal RF and LO Baluns for Single-Ended
Inputs
oBuilt-In SPDT LO Switch with 46dB LO1-to-LO2
Isolation and 50ns Switching Time
oPin Compatible with the MAX19995/MAX19995A
Series of 1700MHz to 2200MHz Mixers
oPin Similar to the MAX19997A/MAX19999 Series
of 1850MHz to 3800MHz Mixers
oSingle +5.0V or +3.3V Supply
oExternal Current-Setting Resistors Provide Option
for Operating Device in Reduced-Power/Reduced-
Performance Mode
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
________________________________________________________________
Maxim Integrated Products
1
19-4185; Rev 0; 8/08
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
cdma2000 is a registered trademark of Telecommunications
Industry Association.
WiMAX is a trademark of WiMAX Forum.
iDEN is a registered trademark of Motorola, Inc.
Typical Application Circuit and Pin Configuration appear at
end of data sheet.
+
Denotes a lead-free/RoHS-compliant package.
*
EP = Exposed pad.
T = Tape and reel.
Ordering Information
PART TEMP RANGE PIN-PACKAGE
MAX19985AETX+
-40°C to +85°C
36 Thin QFN-EP*
MAX19985AETX+T
-40°C to +85°C
36 Thin QFN-EP*
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
+3.3V SUPPLY DC ELECTRICAL CHARACTERISTICS
(
Typical Application Circuit
, VCC = 3.0V to 3.6V, TC= -40°C to +85°C. Typical values are at VCC = 3.3V, TC= +25°C, all parameters
are guaranteed by design and not production tested, 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.
Note 1: Based on junction temperature TJ= TC+ (θJC x VCC x ICC). This formula can be used when the temperature of the exposed
pad is known while the device is soldered down to a PCB. See the
Applications Information
section for details. The junction
temperature must not exceed +150°C.
Note 2: Junction temperature TJ= TA+ (θJA x VCC x ICC). This formula can be used when the ambient temperature of the PCB is
known. The junction temperature must not exceed +150°C.
Note 3: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
Note 4: TCis the temperature on the exposed pad of the package. TAis the ambient temperature of the device and PCB.
VCC to GND...........................................................-0.3V to +5.5V
LO1, LO2 to GND ...............................................................±0.3V
Any Other Pins to GND...............................-0.3V to (VCC + 0.3V)
RFMAIN, RFDIV, and LO_ Input Power ..........................+15dBm
RFMAIN, RFDIV Current (RF is DC shorted
to GND through balun)....................................................50mA
Continuous Power Dissipation (Note 1) ..............................8.8W
θJA (Notes 2, 3)..............................................................+38°C/W
θJC (Note 3).....................................................................7.4°C/W
Operating Temperature Range (Note 4).....TC= -40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
Supply Voltage VCC R2 = R5 = 600Ω3.0 3.3 3.6 V
Supply Current ICC Total supply current, VCC = 3.3V
280
mA
LOSEL Input High Voltage VIH 2V
LOSEL Input Low Voltage VIL 0.8 V
+5.0V SUPPLY DC ELECTRICAL CHARACTERISTICS
(
Typical Application Circuit
, VCC = 4.75V to 5.25V, TC= -40°C to +85°C. Typical values are at VCC = 5.0V, TC= +25°C, all parame-
ters are production tested, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
Supply Voltage VCC
4.75
5
5.25
V
Supply Current ICC
330
380 mA
LOSEL Input High Voltage VIH 2V
LOSEL Input Low Voltage VIL 0.8 V
LOSEL Input Current IIH, IIL -10
+10
µA
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
_______________________________________________________________________________________ 3
RECOMMENDED AC OPERATING CONDITIONS
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
RF Frequency f
RF
(Note 5)
700 1000
MHz
LO Frequency f
LO
(Note 5)
900 1300
MHz
U si ng M i ni - C i r cui ts TC 4- 1W- 17 4:1 tr ansfor m er
as defined in the Typical Application Circuit,
IF matching components affect the IF
frequency range (Note 5)
100
500
IF Frequency f
IF
Using alternative Mini-Circuits TC4-1W-7A
4:1 transformer, IF matching components
affect the IF frequency range (Note 5)
50 250
MHz
LO Drive Level P
LO
(Note 5) -3 +3
dBm
+5.0V SUPPLY AC ELECTRICAL CHARACTERISTICS
(
Typical Application Circuit
, VCC = +4.75V to +5.25V, RF and LO ports are driven from 50Ωsources, PLO = -3dBm to +3dBm,
PRF = -5dBm, fRF = 700MHz to 1000MHz, fLO = 900MHz to 1200MHz, fIF = 200MHz, fRF < fLO, TC= -40°C to +85°C. Typical values
are at VCC = +5.0V, PRF = -5dBm, PLO = 0dBm, fRF =900MHz, fLO = 1100MHz, fIF = 200MHz, TC=+25°C, all parameters are guaran-
teed by design and characterization, unless otherwise noted.) (Note 6)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
f
IF
= 200MHz, f
RF
= 824MHz to 915MHz,
T
C
= -40°C to +85°C 7.0 8.7
10.2
Conversion Power Gain G
C
f
IF
= 200MHz, f
RF
= 824MHz to 915MHz,
T
C
= +25°C (Note 9) 7.7 8.7 9.7
dB
Conversion Power Gain Variation
vs. Frequency ΔG
C
Flatness over any one of three frequency
bands:
f
RF
= 824MHz to 849MHz,
f
RF
= 869MHz to 894MHz,
f
RF
= 880MHz to 915MHz (Note 9)
0.15
0.3 dB
G ai n V ar i ati on Over Tem p er atur eTC
G
T
C
= -40°C to +85°C
-0.012
dB/°C
T
C
= -40°C to +85°C 9.2
11.5
Noise Figure NF f
RF
= 850MHz, f
IF
= 200MHz,
P
LO
= 0d Bm , T
C
= + 25°C , V
C C
= + 5.0V 9.0
10.3
dB
Noise Figure Temperature
Coefficient TC
NF
T
C
= -40°C to +85°C
0.018
dB/°C
Noise Figure Under Blocking
Condition N
FB
+8dBm blocker tone applied to RF port,
f
RF
= 900MHz, f
LO
= 1090MHz,
P
LO
= -3dBm, f
BLOCKER
= 800MHz,
V
CC
= +5.0V (Note 7)
18.8
22 dB
T
C
= -40°C to +85°C
10.0 12.6
Input 1dB Compression Point IP
1dB
T
C
= +25°C (Note 9)
11.0 12.6
dBm
f
RF
= 824MHz to 915MHz,
f
RF1
- f
RF2
= 1MHz, f
IF
= 200MHz,
P
RF
= -5dBm/tone, T
C
= -40°C to +85°C
22.5 25.5
Third-Order Input Intercept Point
IIP3 f
RF
= 824MHz to 915MHz,
f
RF1
- f
RF2
= 1MHz, f
IF
= 200MHz,
P
RF
= -5dBm/tone, T
C
= +25°C (Note 9)
23.5 25.5
dBm
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
4 _______________________________________________________________________________________
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
PRF = -10dBm -63 -76
2LO-2RF Spur Rejection 2 x 2
fRF = 800MHz,
fLO = 1000MHz,
fSPUR = 900MHz
PRF = -5dBm
(Note 9) -58 -71 dBc
PRF = -10dBm -65 -78
3LO-3RF Spur Rejection 3 x 3
fRF = 800MHz,
fLO = 1000MHz,
fSPUR = 933.3MHz
PRF = -5dBm
(Note 9) -60 -73 dBc
LO Leakage at RF Port fLO = 900MHz to 1300MHz, PLO = +3dBm
(Note 10) -40 -20
dBm
fLO = 900MHz to 1200MHz, PLO = +3dBm
(Note 10) -38 -25
2LO Leakage at RF Port fL O = 1200M H z to 1300M H z, P
L O = + 3d Bm
(Note 10) -35 -22
dBm
3LO Leakage at RF Port fLO = 900MHz to 1300MHz, PLO = +3dBm
(Note 10) -50 -28
dBm
4LO Leakage at RF Port fLO = 900MHz to 1300MHz, PLO = +3dBm
(Note 9) -25 -15
dBm
LO Leakage at IF Port fLO = 900MHz to 1300MHz, PLO = +3dBm
(Note 10) -35 -23
dBm
RF-to-IF Isolation fRF = 824MHz to 915MHz (Note 10) 30 38 dB
LO-to-LO Isolation
PLO1 = +3dBm, PLO2 = +3dBm,
fLO1 = 900MHz, fLO2 = 901MHz,
PRF = -5dBm (Notes 8, 10)
40 46 dB
Channel-to-Channel Isolation
RFM AIN ( RFD IV ) conver ted p ow er m easur ed
at IFD IV ( IFM AIN ) , r el ati ve to IFM AIN ( IFD IV ) ,
al l unused p or ts ter m i nated to 50Ω ( N ote 9)
40 48 dB
LO Switching Time 50% of LOS E L to IF settl ed w i thi n 2 d eg r ees 50
1000
ns
RF Input Impedance ZRF 50 Ω
RF Input Return Loss LO on and IF terminated into matched
impedance 20 dB
LO Input Impedance ZLO 50 Ω
RF and IF terminated into matched
impedance, LO port selected 20
LO Input Return Loss RF and IF terminated into matched
impedance, LO port unselected 20
dB
IF Terminal Output Impedance ZIF Nominal differential impedance at the IC’s
IF output
200
Ω
IF Return Loss
RF terminated in 50Ω; transformed to 50Ω
using external components shown in the
Typical Application Circuit
18 dB
+5.0V SUPPLY AC ELECTRICAL CHARACTERISTICS (continued)
(
Typical Application Circuit
, VCC = +4.75V to +5.25V, RF and LO ports are driven from 50Ωsources, PLO = -3dBm to +3dBm,
PRF = -5dBm, fRF = 700MHz to 1000MHz, fLO = 900MHz to 1200MHz, fIF = 200MHz, fRF < fLO, TC= -40°C to +85°C. Typical values
are at VCC = +5.0V, PRF = -5dBm, PLO = 0dBm, fRF =900MHz, fLO = 1100MHz, fIF = 200MHz, TC=+25°C, all parameters are guaran-
teed by design and characterization, unless otherwise noted.) (Note 6)
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
_______________________________________________________________________________________ 5
+3.3V SUPPLY AC ELECTRICAL CHARACTERISTICS
(
Typical Application Circuit
, RF and LO ports are driven from 50Ωsources. Typical values are at VCC = +3.3V, PRF = -5dBm,
PLO = 0dBm, fRF = 900MHz, fLO = 1100MHz, fIF = 200MHz, TC=+25°C, unless otherwise noted.) (Note 6)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
Conversion Power Gain G
C
8.7 dB
Conversion Power Gain Variation
vs. Frequency ΔG
C
Flatness over any one of three frequency
bands:
f
RF
= 824MHz to 849MHz,
f
RF
= 869MHz to 894MHz,
f
RF
= 880MHz to 915MHz
0.15
dB
G ai n V ar i ati on Over Tem p er atur eTC
G
T
C
= -40°C to +85°C
-0.012
dB/°C
Noise Figure NF 9.0 dB
Noise Figure Temperature
Coefficient TC
NF
T
C
= -40°C to +85°C
0.018
dB/°C
Input 1dB Compression Point IP
1dB
10.6
dBm
Third-Order Input Intercept Point
IIP3 f
RF1
= 900MHz, f
RF2
= 901MHz,
f
IF
= 200MHz, P
RF
= -5dBm/tone
24.7
dBm
P
RF
= -10dBm
-74.9
2LO-2RF Spur Rejection 2 x 2
f
RF
= 800MHz,
f
LO
= 1000MHz,
f
SPUR
= 900MHz P
RF
= -5dBm
-69.9
dBc
P
RF
= -10dBm -78
3LO-3RF Spur Rejection 3 x 3
f
RF
= 800MHz,
f
LO
= 1000MHz,
f
SPUR
= 933.333MHz P
RF
= -5dBm -73
dBc
Maximum LO Leakage at RF Port
f
LO
= 900MHz to 1300MHz, P
LO
= +3dBm -40
dBm
M axi m um 2LO Leakag e at RF P or t
f
LO
= 900MHz to 1300MHz, P
LO
= +3dBm -42
dBm
Maximum LO Leakage at IF Port
f
LO
= 900MHz to 1300MHz, P
LO
= +3dBm -34
dBm
Minimum RF-to-IF Isolation f
RF
= 824MHz to 915MHz 38 dB
LO-to-LO Isolation P
LO1
= +3dBm, P
LO2
= +3dBm,
f
LO1
= 900MHz, f
LO2
= 901MHz (Note 8) 45 dB
Channel-to-Channel Isolation
RFM AIN ( RFD IV ) conver ted p ow er m easur ed
at IFD IV ( IFM AIN ) , r el ati ve to IFM AIN ( IFD IV ) ,
al l unused p or ts ter m i nated to 50Ω
48 dB
LO Switching Time 50% of LOS E L to IF settl ed w i thi n 2 d eg r ees 50 ns
RF Input Impedance Z
RF
50 Ω
RF Input Return Loss LO on and IF terminated into matched
impedance 21 dB
LO Input Impedance Z
LO
50 Ω
RF and IF terminated into matched
impedance, LO port selected 31
LO Input Return Loss RF and IF terminated into matched
impedance, LO port unselected 24
dB
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
6 _______________________________________________________________________________________
Note 5: Not production tested. Operation outside this range is possible, but with degraded performance of some parameters. See
the
Typical Operating Characteristics
. Performance is optimized for RF frequencies of 824MHz to 915MHz.
Note 6: All limits reflect losses of external components. Output measurements taken at IF outputs of
Typical Application Circuit
.
Note 7: Measured with external LO source noise filtered so the noise floor is -174dBm/Hz. This specification reflects the effects of
all SNR degradations in the mixer including the LO noise, as defined in the Application Note 2021:
Specifications and
Measurement of Local Oscillator Noise in Integrated Circuit Base Station Mixers
.
Note 8: Measured at IF port at IF frequency. LOSEL may be in any logic state.
Note 9: Limited production testing.
Note 10: Guaranteed by production testing.
+3.3V SUPPLY AC ELECTRICAL CHARACTERISTICS (continued)
(
Typical Application Circuit
, RF and LO ports are driven from 50Ωsources. Typical values are at VCC = +3.3V, PRF = -5dBm,
PLO = 0dBm, fRF = 900MHz, fLO = 1100MHz, fIF = 200MHz, TC=+25°C, unless otherwise noted.) (Note 6)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX UNITS
IF Terminal Output Impedance ZIF Nominal differential impedance at the IC’s
IF output
200
Ω
IF Output Return Loss
RF terminated in 50Ω; transformed to 50Ω
using external components shown in the
Typical Application Circuit
17 dB
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
_______________________________________________________________________________________ 7
Typical Operating Characteristics
(
Typical Application Circuit
, VCC = +5.0V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
CONVERSION GAIN vs. RF FREQUENCY
MAX19985A toc01
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900800
7
8
9
10
11
6
700 1000
TC = +85°CTC = +25°C
TC = -30°C
CONVERSION GAIN vs. RF FREQUENCY
MAX19985A toc02
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900800
7
8
9
10
11
6
700 1000
PLO = -3dBm, 0dBm, +3dBm
CONVERSION GAIN vs. RF FREQUENCY
MAX19985A toc03
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900800
7
8
9
10
11
6
700 1000
VCC = 4.75V, 5.0V, 5.25V
INPUT IP3 vs. RF FREQUENCY
MAX19985A toc04
RF FREQUENCY (MHz)
INPUT IP3 (dBm)
900800
23
24
25
26
27
22
700 1000
TC = +85°C
TC = +25°C
TC = -30°C
PRF = -5dBm/TONE
INPUT IP3 vs. RF FREQUENCY
MAX19985A toc05
RF FREQUENCY (MHz)
INPUT IP3 (dBm)
900800
23
24
25
26
27
22
700 1000
PLO = +3dBm, 0dBm PLO = -3dBm
PRF = -5dBm/TONE
INPUT IP3 vs. RF FREQUENCY
MAX19985A toc06
RF FREQUENCY (MHz)
INPUT IP3 (dBm)
900800
23
24
25
26
27
22
700 1000
VCC = 5.0V
VCC = 5.25V
VCC = 4.75V
PRF = -5dBm/TONE
NOISE FIGURE vs. RF FREQUENCY
MAX19985A toc07
RF FREQUENCY (MHz)
NOISE FIGURE (dB)
900800
7
6
8
9
10
11
12
5
700 1000
TC = +85°C
TC = +25°C
TC = -30°C
NOISE FIGURE vs. RF FREQUENCY
MAX19985A toc08
RF FREQUENCY (MHz)
NOISE FIGURE (dB)
900800
7
6
8
9
10
11
12
5
700 1000
PLO = -3dBm, 0dBm, +3dBm
NOISE FIGURE vs. RF FREQUENCY
MAX19985A toc09
RF FREQUENCY (MHz)
NOISE FIGURE (dB)
900800
7
6
8
9
10
11
12
5
700 1000
VCC = 4.75V, 5.0V, 5.25V
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
8 _______________________________________________________________________________________
2LO-2RF RESPONSE vs. RF FREQUENCY
MAX19985A toc10
RF FREQUENCY (MHz)
2LO-2RF RESPONSE (dBc)
900800
55
60
65
70
75
80
50
700 1000
TC = +85°C
PRF = -5dBm
TC = +25°C
TC = -30°C
2LO-2RF RESPONSE vs. RF FREQUENCY
MAX19985A toc11
RF FREQUENCY (MHz)
2LO-2RF RESPONSE (dBc)
900800
55
60
65
70
75
80
50
700 1000
PLO = 0dBm
PLO = +3dBm
PLO = -3dBm
PRF = -5dBm
2LO-2RF RESPONSE vs. RF FREQUENCY
MAX19985A toc12
RF FREQUENCY (MHz)
2LO-2RF RESPONSE (dBc)
900800
55
60
65
70
75
80
50
700 1000
PRF = -5dBm
VCC = 4.75V, 5.0V, 5.25V
3LO-3RF RESPONSE vs. RF FREQUENCY
MAX19985A toc13
RF FREQUENCY (MHz)
3LO-3RF RESPONSE (dBc)
900800
65
75
85
95
55
700 1000
PRF = -5dBm
TC = +85°CTC = +25°C
TC = -30°C
3LO-3RF RESPONSE vs. RF FREQUENCY
MAX19985A toc14
RF FREQUENCY (MHz)
3LO-3RF RESPONSE (dBc)
900800
65
75
85
95
55
700 1000
PRF = -5dBm
PLO = -3dBm, 0dBm, +3dBm
3LO-3RF RESPONSE vs. RF FREQUENCY
MAX19985A toc15
RF FREQUENCY (MHz)
3LO-3RF RESPONSE (dBc)
900800
65
75
85
95
55
700 1000
PRF = -5dBm
VCC = 4.75V, 5.0V, 5.25V
INPUT P1dB vs. RF FREQUENCY
MAX19985A toc16
RF FREQUENCY (MHz)
INPUT P1dB (dBm)
900800
11
13
12
14
15
10
700 1000
TC = +85°C
TC = +25°C
TC = -30°C
INPUT P1dB vs. RF FREQUENCY
MAX19985A toc17
RF FREQUENCY (MHz)
INPUT P1dB (dBm)
900800
11
13
12
14
15
10
700 1000
PLO = -3dBm, 0dBm, +3dBm
INPUT P1dB vs. RF FREQUENCY
MAX19985A toc18
RF FREQUENCY (MHz)
INPUT P1dB (dBm)
900800
11
13
12
14
15
10
700 1000
VCC = 5.0V
VCC = 5.25V
VCC = 4.75V
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, VCC = +5.0V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
_______________________________________________________________________________________ 9
CHANNEL ISOLATION vs. RF FREQUENCY
MAX19985A toc19
RF FREQUENCY (MHz)
CHANNEL ISOLATION (dB)
900800
40
35
50
45
55
60
30
700 1000
TC = -30°C, +25°C, +85°C
CHANNEL ISOLATION vs. RF FREQUENCY
MAX19985A toc20
RF FREQUENCY (MHz)
CHANNEL ISOLATION (dB)
900800
40
35
50
45
55
60
30
700 1000
PLO = -3dBm, 0dBm, +3dBm
CHANNEL ISOLATION vs. RF FREQUENCY
MAX19985A toc21
RF FREQUENCY (MHz)
CHANNEL ISOLATION (dB)
900800
40
35
50
45
55
60
30
700 1000
VCC = 4.75V, 5.0V, 5.25V
LO LEAKAGE AT IF PORT
vs. LO FREQUENCY
MAX19985A toc22
LO FREQUENCY (MHz)
LO LEAKAGE AT IF PORT (dBm)
1100 11501000 1050950
-40
-45
-30
-35
-25
-20
-50
900 1200
TC = -30°C
TC = +25°C, +85°C
LO LEAKAGE AT IF PORT
vs. LO FREQUENCY
MAX19985A toc23
LO FREQUENCY (MHz)
LO LEAKAGE AT IF PORT (dBm)
1150110010501000950
-45
-40
-35
-30
-25
-20
-50
900 1200
PLO = +3dBm
PLO = 0dBm
PLO = -3dBm
LO LEAKAGE AT IF PORT
vs. LO FREQUENCY
MAX19985A toc24
LO FREQUENCY (MHz)
LO LEAKAGE AT IF PORT (dBm)
1150110010501000950
-45
-40
-35
-30
-25
-20
-50
900 1200
VCC = 4.75V, 5.0V, 5.25V
RF-TO-IF ISOLATION
vs. RF FREQUENCY
MAX19985A toc25
RF FREQUENCY (MHz)
RF-TO-IF ISOLATION (dB)
800 900
45
40
35
50
30
700 1000
TC = +85°C
TC = -30°C TC = +25°C
RF-TO-IF ISOLATION
vs. RF FREQUENCY
MAX19985A toc26
RF FREQUENCY (MHz)
RF-TO-IF ISOLATION (dB)
800 900
45
40
35
50
30
700 1000
PLO = -3dBm, 0dBm, +3dBm
RF-TO-IF ISOLATION
vs. RF FREQUENCY
MAX19985A toc27
RF FREQUENCY (MHz)
RF-TO-IF ISOLATION (dB)
800 900
45
40
35
50
30
700 1000
VCC = 4.75V, 5.0V, 5.25V
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, VCC = +5.0V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
10 ______________________________________________________________________________________
LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc28
LO FREQUENCY (MHz)
LO LEAKAGE AT RF PORT (dBm)
800 900 11001000
-60
-50
-40
-30
-20
-70
700 1200
TC = -30°C
TC = +85°C
TC = +25°C
LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc29
LO FREQUENCY (MHz)
LO LEAKAGE AT RF PORT (dBm)
800 900 11001000
-60
-50
-40
-30
-20
-70
700 1200
PLO = -3dBm, 0dBm, +3dBm
LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc30
LO FREQUENCY (MHz)
LO LEAKAGE AT RF PORT (dBm)
800 900 11001000
-60
-50
-40
-30
-20
-70
700 1200
VCC = 4.75V, 5.0V, 5.25V
2LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc31
LO FREQUENCY (MHz)
2LO LEAKAGE AT RF PORT (dBm)
800 900 11001000
-50
-40
-30
-20
-10
-60
700 1200
TC = -30°C, +25°C, +85°C
2LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc32
LO FREQUENCY (MHz)
2LO LEAKAGE AT RF PORT (dBm)
800 900 11001000
-50
-40
-30
-20
-10
-60
700 1200
PLO = -3dBm, 0dBm, +3dBm
2LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc33
LO FREQUENCY (MHz)
2LO LEAKAGE AT RF PORT (dBm)
800 900 11001000
-50
-40
-30
-20
-10
-60
700 1200
VCC = 4.75V, 5.0V, 5.25V
LO SWITCH ISOLATION
vs. LO FREQUENCY
MAX19985A toc34
LO FREQUENCY (MHz)
LO SWITCH ISOLATION (dB)
1100 1300
45
40
35
50
30
900 15001000 1200 1400
TC = +85°C
TC = -30°C
TC = +25°C
LO SWITCH ISOLATION
vs. LO FREQUENCY
MAX19985A toc35
LO FREQUENCY (MHz)
LO SWITCH ISOLATION (dB)
1100 1300
45
40
35
50
30
900 15001000 1200 1400
PLO = +3dBm
PLO = -3dBm, 0dBm
LO SWITCH ISOLATION
vs. LO FREQUENCY
MAX19985A toc36
LO FREQUENCY (MHz)
LO SWITCH ISOLATION (dB)
1100 1300
45
40
35
50
30
900 15001000 1200 1400
VCC = 4.75V, 5.0V, 5.25V
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, VCC = +5.0V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
3LO-3RF RESPONSE vs. RF FREQUENCY
(VARIOUS LO AND IF BIAS)
MAX19985A toc45
RF FREQUENCY (MHz)
3LO-3RF RESPONSE (dBc)
900800
60
65
55
75
50
70
80
85
45
700 1000
SEE TABLE 1 FOR RESISTOR AND ICC VALUES
1, 2, 3, 4 PRF = -5dBm
5
76
2LO-2RF RESPONSE vs. RF FREQUENCY
(VARIOUS LO AND IF BIAS)
MAX19985A toc44
RF FREQUENCY (MHz)
2LO-2RF RESPONSE (dBc)
900800
60
65
55
70
75
80
50
700 1000
SEE TABLE 1 FOR RESISTOR AND ICC VALUES
2, 3, 4
1PRF = -5dBm
5
76
LO SELECTED RETURN LOSS
vs. LO FREQUENCY
MAX19985A toc39
LO FREQUENCY (MHz)
LO SELECTED RETURN LOSS (dB)
11001000850
40
30
20
10
0
50
700 1300
PLO = +3dBm
PLO = 0dBm
PLO = -3dBm
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
______________________________________________________________________________________ 11
RF PORT RETURN LOSS
vs. RF FREQUENCY
MAX19985A toc37
RF FREQUENCY (MHz)
RF PORT RETURN LOSS (dB)
900 950800750 850
25
20
15
10
5
0
30
700 1000
PLO = -3dBm, 0dBm, +3dBm
IF = 200MHz
IF PORT RETURN LOSS
vs. IF FREQUENCY
MAX19985A toc38
IF FREQUENCY (MHz)
IF PORT RETURN LOSS (dB)
140 230 320 410
25
20
15
10
5
0
30
50 500
LO = 900MHz
VCC = 4.75V, 5.0V, 5.25V
IF RETURN LOSS DEPENDS ON
EXTERNAL IF COMPONENTS
LO UNSELECTED RETURN LOSS
vs. LO FREQUENCY
MAX19985A toc40
LO FREQUENCY (MHz)
LO UNSELECTED RETURN LOSS (dB)
11001000850
40
30
20
10
0
50
700 1300
PLO = -3dBm, 0dBm, +3dBm
SUPPLY CURRENT
vs. TEMPERATURE (TC)
MAX19985A toc41
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
-15 25 45565
290
310
330
350
370
270
-35 85
VCC = 5.25V
VCC = 4.75V
VCC = 5.0V
CONVERSION GAIN vs. RF FREQUENCY
(VARIOUS LO AND IF BIAS)
MAX19985A toc42
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900800
7
8
9
10
11
6
700 1000
SEE TABLE 1 FOR RESISTOR AND ICC VALUES
1, 2, 3, 4
75
6
INPUT IP3 vs. RF FREQUENCY
(VARIOUS LO AND IF BIAS)
MAX19985A toc43
RF FREQUENCY (MHz)
INPUT IP3 (dBm)
900800
20
22
16
18
24
26
28
14
700 1000
SEE TABLE 1 FOR RESISTOR AND ICC VALUES
2, 3, 4
11
4
5
7
6
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, VCC = +5.0V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
12 ______________________________________________________________________________________
INPUT P1dB vs. RF FREQUENCY
(VARIOUS LO AND IF BIAS)
MAX19985A toc46
RF FREQUENCY (MHz)
INPUT P1dB (dBm)
900800
10
8
14
6
12
16
4
700 1000
SEE TABLE 1 FOR RESISTOR AND ICC VALUES
1, 2, 3, 4
5
76
CONVERSION GAIN vs. RF FREQUENCY
(VARIOUS VALUES OF L3 AND L6)
MAX19985A toc47
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900
L = L3 = L6
800
8
7
10
9
11
6
700 1000
L = 0Ω, 7.5nH, 15nH, 30nH
INPUT IP3 vs. RF FREQUENCY
(VARIOUS VALUES OF L3 AND L6)
MAX19985A toc48
RF FREQUENCY (MHz)
INPUT IP3 (dBm)
900
L = L3 = L6
800
24
23
26
25
27
22
700 1000
L = 0Ω, 7.5nH, 15nH
L = 30nH
2LO-2RF RESPONSE vs. RF FREQUENCY
(VARIOUS VALUES OF L3 AND L6)
MAX19985A toc49
RF FREQUENCY (MHz)
2LO-2RF RESPONSE (dBc)
900
PRF = -5dBm
L = L3 = L6
800
65
60
55
75
70
80
50
700 1000
L = 30nH
L = 7.5nH L = 15nH
L = 0Ω
3LO-3RF RESPONSE vs. RF FREQUENCY
(VARIOUS VALUES OF L3 AND L6)
MAX19985A toc50
RF FREQUENCY (MHz)
3LO-3RF RESPONSE (dBc)
900
PRF = -5dBm
L = L3 = L6
800
75
65
85
95
55
700 1000
L = 0Ω, 7.5nH, 15nH, 30nH
LO LEAKAGE AT IF PORT vs. LO FREQUENCY
(VARIOUS VALUES OF L3 AND L6)
MAX19985A toc51
LO FREQUENCY (MHz)
LO LEAKAGE AT IF PORT (dBm)
11001000
-20
-30
-10
-50
-60
-40
0
-70
900 12001050950 1150
L = 0Ω
L = 7.5nH
L = 30nH
L = 15nH
L = L3 = L6
RF-TO-IF ISOLATION vs. RF FREQUENCY
(VARIOUS VALUES OF L3 AND L6)
MAX19985A toc52
RF FREQUENCY (MHz)
RF-TO-IF ISOLATION (dB)
900800
40
20
10
30
50
0
700 1000
L = 0Ω
L = 7.5nH
L = 30nH L = 15nH L = L3 = L6
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, VCC = +5.0V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
______________________________________________________________________________________ 13
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, VCC = +3.3V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
CONVERSION GAIN
vs. RF FREQUENCY
MAX19985A toc53
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
900800
10
8
7
9
11
6
700 1000
TC = +85°C
TC = -30°C
TC = +25°C
VCC = 3.3V
CONVERSION GAIN
vs. RF FREQUENCY
MAX19985A toc54
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
800 900
7
8
9
10
11
6
700 1000
PLO = -3dBm, 0dBm, +3dBm
VCC = 3.3V
CONVERSION GAIN
vs. RF FREQUENCY
MAX19985A toc55
RF FREQUENCY (MHz)
CONVERSION GAIN (dB)
800 900
7
8
9
10
11
6
700 1000
VCC = 3.0V, 3.3V, 3.6V
INPUT IP3 vs. RF FREQUENCY
MAX19985A toc56
RF FREQUENCY (MHz)
INPUT IP3 (dBm)
900800
25
23
22
24
26
21
700 1000
TC = +85°C
TC = -30°C
TC = +25°C
VCC = 3.3V
PRF = -5dBm/TONE
INPUT IP3 vs. RF FREQUENCY
MAX19985A toc57
RF FREQUENCY (MHz)
INPUT IP3 (dBm)
900800
25
23
22
24
26
21
700 1000
PLO = +3dBm
PLO = -3dBm
PLO = 0dBm
VCC = 3.3V
PRF = -5dBm/TONE
INPUT IP3 vs. RF FREQUENCY
MAX19985A toc58
RF FREQUENCY (MHz)
INPUT IP3 (dBm)
900800
25
23
22
24
26
21
700 1000
VCC = 3.6V
VCC = 3.0V
VCC = 3.3V
PRF = -5dBm/TONE
NOISE FIGURE
vs. RF FREQUENCY
MAX19985A toc59
RF FREQUENCY (MHz)
NOISE FIGURE (dB)
900800
11
8
7
10
6
9
12
5
700 1000
TC = +85°C
TC = -30°C TC = +25°C
VCC = 3.3V
NOISE FIGURE
vs. RF FREQUENCY
MAX19985A toc60
RF FREQUENCY (MHz)
NOISE FIGURE (dB)
900800
11
8
7
10
6
9
12
5
700 1000
PLO = -3dBm, 0dBm, +3dBm
VCC = 3.3V
NOISE FIGURE
vs. RF FREQUENCY
MAX19985A toc61
RF FREQUENCY (MHz)
NOISE FIGURE (dB)
900800
11
8
7
10
6
9
12
5
700 1000
VCC = 3.0V, 3.3V, 3.6V
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
14 ______________________________________________________________________________________
2LO-2RF RESPONSE
vs. RF FREQUENCY
MAX19985A toc62
RF FREQUENCY (MHz)
2LO-2RF RESPONSE (dBc)
900800
75
60
55
70
65
80
50
700 1000
TC = +85°C
PRF = -5dBm
TC = -30°C
TC = +25°C
VCC = 3.3V
2LO-2RF RESPONSE
vs. RF FREQUENCY
MAX19985A toc63
RF FREQUENCY (MHz)
2LO-2RF RESPONSE (dBc)
900800
75
60
55
70
65
80
50
700 1000
PRF = -5dBm
PLO = +3dBm
PLO = -3dBm
PLO = 0dBm
VCC = 3.3V
2LO-2RF RESPONSE
vs. RF FREQUENCY
MAX19985A toc64
RF FREQUENCY (MHz)
2LO-2RF RESPONSE (dBc)
900800
75
60
55
70
65
80
50
700 1000
PRF = -5dBm
VCC = 3.0V, 3.3V, 3.6V
3LO-3RF RESPONSE
vs. RF FREQUENCY
MAX19985A toc65
RF FREQUENCY (MHz)
3LO-3RF RESPONSE (dBc)
900800
65
85
75
95
55
700 1000
TC = +85°C
PRF = -5dBm
TC = -30°C
TC = +25°C
VCC = 3.3V
3LO-3RF RESPONSE
vs. RF FREQUENCY
MAX19985A toc66
RF FREQUENCY (MHz)
3LO-3RF RESPONSE (dBc)
900800
65
85
75
95
55
700 1000
PRF = -5dBm
PLO = -3dBm, 0dBm, +3dBm
VCC = 3.3V
3LO-3RF RESPONSE
vs. RF FREQUENCY
MAX19985A toc67
RF FREQUENCY (MHz)
3LO-3RF RESPONSE (dBc)
900800
65
85
75
95
55
700 1000
PRF = -5dBm
VCC = 3.6V
VCC = 3.0V
VCC = 3.3V
INPUT P1dB vs. RF FREQUENCY
MAX19985A toc68
RF FREQUENCY (MHz)
INPUT P1dB (dBm)
900800
9
12
8
11
10
13
7
700 1000
TC = +85°C
TC = -30°C
TC = +25°C
VCC = 3.3V
INPUT P1dB vs. RF FREQUENCY
MAX19985A toc69
RF FREQUENCY (MHz)
INPUT P1dB (dBm)
900800
9
12
8
11
10
13
7
700 1000
PLO = -3dBm, 0dBm, +3dBm
VCC = 3.3V
INPUT P1dB vs. RF FREQUENCY
MAX19985A toc70
RF FREQUENCY (MHz)
INPUT P1dB (dBm)
900800
9
12
8
11
10
13
7
700 1000
VCC = 3.6V
VCC = 3.0V
VCC = 3.3V
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, VCC = +3.3V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
______________________________________________________________________________________ 15
CHANNEL ISOLATION
vs. RF FREQUENCY
MAX19985A toc71
RF FREQUENCY (MHz)
CHANNEL ISOLATION (dB)
900800
40
55
35
50
45
60
30
700 1000
TC = -30°C, +25°C, +85°C
VCC = 3.3V
CHANNEL ISOLATION
vs. RF FREQUENCY
MAX19985A toc72
RF FREQUENCY (MHz)
CHANNEL ISOLATION (dB)
900800
40
55
35
50
45
60
30
700 1000
PLO = -3dBm, 0dBm, +3dBm
VCC = 3.3V
CHANNEL ISOLATION
vs. RF FREQUENCY
MAX19985A toc73
RF FREQUENCY (MHz)
CHANNEL ISOLATION (dB)
900800
40
55
35
50
45
60
30
700 1000
VCC = 3.0V, 3.3V, 3.6V
LO LEAKAGE AT IF PORT
vs. LO FREQUENCY
MAX19985A toc74
LO FREQUENCY (MHz)
LO LEAKAGE AT IF PORT (dBm)
11001000
-40
-25
-45
-30
-35
-20
-50
900 12001050950 1150
TC = +85°C
TC = -30°C
TC = +25°C
VCC = 3.3V
LO LEAKAGE AT IF PORT
vs. LO FREQUENCY
MAX19985A toc75
LO FREQUENCY (MHz)
LO LEAKAGE AT IF PORT (dBm)
11001000
-40
-25
-45
-30
-35
-20
-50
900 12001050950 1150
PLO = +3dBm
PLO = -3dBm
PLO = 0dBm
VCC = 3.3V
LO LEAKAGE AT IF PORT
vs. LO FREQUENCY
MAX19985A toc76
LO FREQUENCY (MHz)
LO LEAKAGE AT IF PORT (dBm)
11001000
-40
-25
-45
-30
-35
-20
-50
900 12001050950 1150
VCC = 3.6V
VCC = 3.0V
VCC = 3.3V
RF-TO-IF ISOLATION
vs. RF FREQUENCY
MAX19985A toc77
RF FREQUENCY (MHz)
RF-TO-IF ISOLATION (dB)
900800
45
35
40
50
30
700 1000
TC = +85°C
TC = -30°C
TC = +25°C
VCC = 3.3V
RF-TO-IF ISOLATION
vs. RF FREQUENCY
MAX19985A toc78
RF FREQUENCY (MHz)
RF-TO-IF ISOLATION (dB)
900800
45
35
40
50
30
700 1000
PLO = -3dBm, 0dBm, +3dBm
VCC = 3.3V
RF-TO-IF ISOLATION
vs. RF FREQUENCY
MAX19985A toc79
RF FREQUENCY (MHz)
RF-TO-IF ISOLATION (dB)
900800
45
35
40
50
30
700 1000
VCC = 3.0V, 3.3V, 3.6V
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, VCC = +3.3V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
16 ______________________________________________________________________________________
LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc80
LO FREQUENCY (MHz)
LO LEAKAGE AT RF PORT (dBm)
800 1000900 1100
-30
-50
-40
-20
-60
700 1200
TC = +85°C
TC = -30°C TC = +25°C
VCC = 3.3V
LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc81
LO FREQUENCY (MHz)
LO LEAKAGE AT RF PORT (dBm)
800 1000900 1100
-30
-50
-40
-20
-60
700 1200
PLO = -3dBm, 0dBm, +3dBm
VCC = 3.3V
LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc82
LO FREQUENCY (MHz)
LO LEAKAGE AT RF PORT (dBm)
800 1000900 1100
-30
-50
-40
-20
-60
700 1200
VCC = 3.6V
VCC = 3.0V
VCC = 3.3V
2LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc83
LO FREQUENCY (MHz)
2LO LEAKAGE AT RF PORT (dBm)
800 1000900 1100
-30
-20
-50
-40
-10
-60
700 1200
TC = -30°C, +25°C, +85°C
VCC = 3.3V
2LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc84
LO FREQUENCY (MHz)
2LO LEAKAGE AT RF PORT (dBm)
800 1000900 1100
-30
-20
-50
-40
-10
-60
700 1200
PLO = -3dBm, 0dBm, +3dBm
VCC = 3.3V
2LO LEAKAGE AT RF PORT
vs. LO FREQUENCY
MAX19985A toc85
LO FREQUENCY (MHz)
2LO LEAKAGE AT RF PORT (dBm)
800 1000900 1100
-30
-20
-50
-40
-10
-60
700 1200
VCC = 3.6V
VCC = 3.0V
VCC = 3.3V
LO SWITCH ISOLATION
vs. RF FREQUENCY
MAX19985A toc86
LO FREQUENCY (MHz)
LO SWITCH ISOLATION (dB)
13001000 1200 14001100
45
35
40
50
30
900 1500
TC = -30°C
TC = +25°C
TC = +85°C
VCC = 3.3V
LO SWITCH ISOLATION
vs. RF FREQUENCY
MAX19985A toc87
LO FREQUENCY (MHz)
LO SWITCH ISOLATION (dB)
13001000 1200 14001100
45
35
40
50
30
900 1500
PLO = -3dBm, 0dBm
PLO = +3dBm
VCC = 3.3V
LO SWITCH ISOLATION
vs. LO FREQUENCY
MAX19985A toc88
LO FREQUENCY (MHz)
LO SWITCH ISOLATION (dB)
13001000 1200 14001100
45
35
40
50
30
900 1500
VCC = 3.0V, 3.3V, 3.6V
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, VCC = +3.3V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
Table 1. DC Current vs. Bias Resistor
Settings
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
______________________________________________________________________________________ 17
RF PORT RETURN LOSS
vs. RF FREQUENCY
MAX19985A toc89
RF FREQUENCY (MHz)
RF PORT RETURN LOSS (dB)
900750 850 950800
5
20
10
25
15
0
30
700 1000
PLO = -3dBm, 0dBm, +3dBm
IF = 200MHz
VCC = 3.3V
IF PORT RETURN LOSS
vs. IF FREQUENCY
MAX19985A toc90
IF FREQUENCY (MHz)
IF PORT RETURN LOSS (dB)
140 230 410
5
20
10
25
15
0
30
50 500320
LO = 900MHz
VCC = 3.0V, 3.3V, 3.6V
IF RETURN LOSS DEPENDS ON
EXTERNAL COMPONENTS
LO SELECTED RETURN LOSS
vs. LO FREQUENCY
MAX19985A toc91
LO FREQUENCY (MHz)
LO SELECTED RETURN LOSS (dB)
1150
30
40
10
20
0
50
700 13001000850
PLO = +3dBm
PLO = -3dBm
PLO = 0dBm
VCC = 3.3V
LO UNSELECTED RETURN LOSS
vs. LO FREQUENCY
MAX19985A toc92
LO FREQUENCY (MHz)
LO UNSELECTED RETURN LOSS (dB)
1150
30
40
10
20
0
50
700 13001000850
PLO = -3dBm, 0dBm, +3dBm
VCC = 3.3V
SUPPLY CURRENT
vs. TEMPERATURE (TC)
MAX19985A toc93
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
455
320
280
260
240
220
300
340
200
-35 8525-15 65
VCC = 3.6V
VCC = 3.0V
VCC = 3.3V
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, VCC = +3.3V, PLO = 0dBm, PRF = -5dBm, LO is high-side injected for a 200MHz IF, TC=+25°C, unless
otherwise noted.)
BIAS
CONDITION
D C CU R R EN T
( m A )
R1 AND R4
VALUES (Ω)
R2 AND R5
VALUES (Ω)
1 359.4 698 800
2 331.8 698 1100
3 322.8 698 1200
4 311.7 698 1400
5 268.2 1100 1200
6 244.4 1400 1200
7 223.7 1820 1200
Note: See TOCs 42–46 for performance trade-offs vs. DC bias
condition.
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
18 ______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1 RFMAIN Main Channel RF input. Internally matched to 50Ω. Requires an input DC-blocking
capacitor.
2 TAPMAIN Main Channel Balun Center Tap. Bypass to GND with 39pF and 0.033µF capacitors as
close as possible to the pin with the smaller value capacitor closer to the part.
3, 5, 7, 12, 20, 22,
24, 25, 26, 34 GND Ground
4, 6, 10, 16, 21,
30, 36 VCC Power Supply. Bypass to GND with 0.01µF capacitors as close as possible to the pin. Pins
4 and 6 do not require bypass capacitors.
8 TAPDIV Diversity Channel Balun Center Tap. Bypass to GND with 39pF and 0.033µF capacitors as
close as possible to the pin with the smaller value capacitor closer to the part.
9 RFDIV Diversity Channel RF Input. Internally matched to 50Ω. Requires an input DC-blocking
capacitor.
11 IFDBIAS
IF Diversity Amplifier Bias Control. Connect a resistor from this pin to ground to set the bias
current for the diversity IF amplifier (see the Typical Operating Characteristics for typical
performance vs. resistor value).
13, 14 IFD+, IFD- Diversity Mixer Differential IF Outputs. Connect pullup inductors from each of these pins to
VCC (see the Typical Application Circuit).
15 LEXTD
Diversity External Inductor Connection. Connect a parallel combination of an inductor and
a 500Ω resistor from this pin to ground to increase the RF-to-IF and LO-to-IF isolation (see
the Typical Operating Characteristics for typical performance vs. inductor value).
17 LODBIAS
LO Diversity Amplifier Bias Control. Connect a resistor from this pin to ground to set the
bias current for the diversity LO amplifier (see the Typical Operating Characteristics for
typical performance vs. resistor value).
18, 28 N.C. No Connection. Not internally connected.
19 LO1 Local Oscillator 1 Input. This input is internally matched to 50Ω. Requires an input DC-
blocking capacitor.
23 LOSEL Local Oscillator Select. Set this pin to high to select LO1. Set to low to select LO2.
27 LO2 Local Oscillator 2 Input. This input is internally matched to 50Ω. Requires an input DC-
blocking capacitor.
29 LOMBIAS
LO Main Amplifier Bias Control. Connect a resistor from this pin to ground to set the bias
current for the main LO amplifier (see the Typical Operating Characteristics for typical
performance vs. resistor value).
31 LEXTM
Main External Inductor Connection. Connect a parallel combination of an inductor and a
500Ω resistor from this pin to ground to increase the RF-to-IF and LO-to-IF isolation (see
Typical Operating Characteristics for typical performance vs. inductor value).
32, 33 IFM-, IFM+ Main Mixer Differential IF Outputs. Connect pullup inductors from each of these pins to VCC
(see the Typical Application Circuit).
35 IFMBIAS
IF Main Amplifier Bias Control. Connect a resistor from this pin to ground to set the bias
current for the main IF amplifier (see the Typical Operating Characteristics for typical
performance vs. resistor value).
—EP
Exposed Pad. Internally connected to GND. Connect to a large ground plane using
multiple vias to maximize thermal and RF performance.
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
______________________________________________________________________________________ 19
Detailed Description
The MAX19985A is a dual-channel downconverter
designed to provide 8.7dB of conversion gain,
+25.5dBm of IIP3, +12.6dBm typical input 1dB com-
pression point, and a 9.0dB noise figure.
In addition to its high-linearity performance, the
MAX19985A achieves a high level of component inte-
gration. The device integrates two double-balanced
mixers for two-channel downconversion. Both the main
and diversity channels include a balun and matching
circuitry to allow 50Ωsingle-ended interfaces to the RF
ports and the two LO ports. An integrated single-pole/
double-throw (SPDT) switch provides 50ns switching
time between the two LO inputs with 46dB of LO-to-LO
isolation and -40dBm of LO leakage at the RF port.
Furthermore, the integrated LO buffers provide a high
drive level to each mixer core, reducing the LO drive
required at the MAX19985A’s inputs to a range of
-3dBm to +3dBm. The IF ports for both channels incor-
porate differential outputs for downconversion, which is
ideal for providing enhanced 2LO-2RF performance.
Specifications are guaranteed over broad frequency
ranges to allow for use in WCDMA, GSM/EDGE, iDEN,
cdma2000, and LTE/WiMAX cellular and 700MHz band
base stations. The MAX19985A is specified to operate
over an RF input range of 700MHz to 1000MHz, an LO
range of 900MHz to 1300MHz, and an IF range of
50MHz to 500MHz. The external IF components set the
lower frequency range (see the
Typical Operating
Characteristics
for details). Operation beyond these
ranges is possible (see the
Typical Operating
Characteristics
for additional information). Although this
device is optimized for high-side LO injection applica-
tions, it can operate in low-side LO injection modes as
well. However, performance degrades as fLO continues
to decrease. For increased low-side LO performance,
refer to the MAX19985 data sheet.
RF Port and Balun
The RF input ports of both the main and diversity chan-
nels are internally matched to 50Ω, requiring no exter-
nal matching components. A DC-blocking capacitor is
required as the input is internally DC shorted to ground
through the on-chip balun. The RF port input return loss
is typically 20dB over the RF frequency range of
770MHz to 915MHz.
LO Inputs, Buffer, and Balun
The MAX19985A is optimized for a 900MHz to
1300MHz LO frequency range. As an added feature,
the MAX19985A includes an internal LO SPDT switch
for use in frequency-hopping applications. The switch
selects one of the two single-ended LO ports, allowing
the external oscillator to settle on a particular frequency
before it is switched in. LO switching time is typically
50ns, which is more than adequate for typical GSM
applications. If frequency hopping is not employed,
simply set the switch to either of the LO inputs. The
switch is controlled by a digital input (LOSEL), where
logic-high selects LO1 and logic-low selects LO2. LO1
and LO2 inputs are internally matched to 50Ω, requiring
only an 82pF DC-blocking capacitor. To avoid damage
to the part, voltage MUST be applied to VCC before
digital logic is applied to LOSEL. Alternatively, a 1kΩ
resistor can be placed in series at the LOSEL to limit
the input current in applications where LOSEL is
applied before VCC.
The main and diversity channels incorporate a two-
stage LO buffer that allows for a wide-input power
range for the LO drive. The on-chip low-loss baluns,
along with LO buffers, drive the double-balanced mix-
ers. All interfacing and matching components from the
LO inputs to the IF outputs are integrated on-chip.
High-Linearity Mixer
The core of the MAX19985A dual-channel downcon-
verter consists of two double-balanced, high-
performance passive mixers. Exceptional linearity is
provided by the large LO swing from the on-chip LO
buffers. When combined with the integrated IF ampli-
fiers, the cascaded IIP3, 2LO-2RF rejection, and noise
figure performance are typically +25.5dBm, 76dBc,
and 9.0dB, respectively.
Differential IF
The MAX19985A has an IF frequency range of 50MHz
to 500MHz, where the low-end frequency depends on
the frequency response of the external IF components.
Note that these differential ports are ideal for providing
enhanced IIP2 performance. Single-ended IF applica-
tions require a 4:1 (impedance ratio) balun to transform
the 200Ωdifferential IF impedance to a 50Ωsingle-
ended system. After the balun, the return loss is
typically 18dB. The user can use a differential IF ampli-
fier on the mixer IF ports, but a DC block is required on
both IFD+/IFD- and IFM+/IFM- ports to keep external
DC from entering the IF ports of the mixer.
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
20 ______________________________________________________________________________________
Applications Information
Input and Output Matching
The RF and LO inputs are internally matched to 50Ω. No
matching components are required. The RF port input
return loss is typically 20dB over the RF frequency range
of 770MHz to 915MHz and return loss at the LO ports are
typically 20dB over the entire LO range. RF and LO inputs
require only DC-blocking capacitors for interfacing.
The IF output impedance is 200Ω(differential). For
evaluation, an external low-loss 4:1 (impedance ratio)
balun transforms this impedance to a 50Ωsingle-ended
output (see the
Typical Application Circuit
).
Externally Adjustable Bias
Each channel of the MAX19985A has two pins (LO_BIAS,
IF_BIAS) that allow external resistors to set the internal
bias currents. Nominal values for these resistors are given
in Table 2. Larger-value resistors can be used to reduce
power dissipation at the expense of some performance
loss. See the
Typical Operating Characteristics
to evaluate
the power vs. performance tradeoff. If ±1% resistors are
not readily available, ±5% resistors can be substituted.
LEXT_ Inductors
For applications requiring optimum RF-to-IF and LO-to-
IF isolation, connect a parallel combination of a low-
ESR inductor and a 500Ωresistor from LEXT_ (pins 15
and 31) to ground. When improved isolation is not
required, connect LEXT_ to ground using a 0Ωresis-
tance. See the
Typical Operating Characteristics
to
evaluate the isolation vs. inductor value tradeoff.
Layout Considerations
A properly designed PCB is an essential part of any
RF/microwave circuit. Keep RF signal lines as short as
possible to reduce losses, radiation, and inductance.
The load impedance presented to the mixer must be so
that any capacitance from both IF- and IF+ to ground
does not exceed several picofarads. For the best perfor-
mance, route the ground pin traces directly to the
exposed pad under the package. The PCB exposed
pad MUST be connected to the ground plane of the
PCB. It is suggested that multiple vias be used to con-
nect this pad to the lower-level ground planes. This
method provides a good RF/thermal-conduction path for
the device. Solder the exposed pad on the bottom of the
Table 2. Component Values
COMPONENT VALUE DESCRIPTION
C1, C2, C7, C8 39pF Microwave capacitors (0402)
C3, C6 0.033µF Microwave capacitors (0603)
C4, C5 — Not used
C9, C13, C15, C17, C18 0.01µF Microwave capacitors (0402)
C10, C11, C12, C19, C20, C21
150pF Microwave capacitors (0603)
C14, C16 82pF Microwave capacitors (0402)
L1, L2, L4, L5 330nH Wire-wound high-Q inductors (0805)
L3, L6 30nH Wire-wound high-Q inductors (0603). Smaller values can be used at the expense of
some performance loss (see the Typical Operating Characteristics).
R1, R4 698Ω±1% resistors (0402). Larger values can be used to reduce power at the expense of
some performance loss (see the Typical Operating Characteristics).
1.2kΩ
±1% resistors (0402). Use for VCC = +5.0V applications. Larger values can be used
to reduce power at the expense of some performance loss (see the Typical
Operating Characteristics).
R2, R5
600Ω±1% resistors (0402). Use for VCC = +3.3V applications.
R3, R6 0Ω±1% resistors (1206)
R7, R8 500Ω±1% resistors (0402)
T1, T2 4:1 Transformers (200:50)
Mini-Circuits TC4-1W-7A
U1 — MAX19985A IC
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
______________________________________________________________________________________ 21
device package to the PCB. The MAX19985A evaluation
kit can be used as a reference for board layout. Gerber
files are available upon request at www.maxim-ic.com.
Power-Supply Bypassing
Proper voltage-supply bypassing is essential for high-
frequency circuit stability. Bypass each VCC pin and
TAPMAIN/TAPDIV with the capacitors shown in the
Typical Application Circuit
(see Table 2 for component
values). Place the TAPMAIN/TAPDIV bypass capacitors
to ground within 100 mils of the pin.
Exposed Pad RF/Thermal Considerations
The exposed pad (EP) of the MAX19985A’s 36-pin thin
QFN-EP package provides a low thermal-resistance
path to the die. It is important that the PCB on which the
MAX19985A is mounted be designed to conduct heat
from the EP. In addition, provide the EP with a low-
inductance path to electrical ground. The EP MUST be
soldered to a ground plane on the PCB, either directly
or through an array of plated via holes.
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
22 ______________________________________________________________________________________
Typical Application Circuit
MAX19985A
5
6
4
3
23
22
24
IFDBIAS
IFD+
IFD-
LEXTD
VCC
25
VCC
IFMBIAS
IFM+
IFM-
VCC
LEXTM
LOMBIAS
10 11
VCC
13 14 15 16
3536 34 32 31 30
GND
VCC
GND
GND
LOSEL
GND
GND GND
12
33
721
GND
GND C15
919
RFDIV LO1
VCC
820
TAPDIV
GND
226 GND
R1
TAPMAIN
127 LO2
LO1
LO2
+
N.C. N.C.
18
28
VCC
LODBIAS
17
29
RFMAIN
L3
L2
L1
EXPOSED
PAD
C16
C20
C19
C21
LO
SELECT
IF MAIN
OUTPUT
IF DIV
OUTPUT
C14
VCC
RF DIV
INPUT
RF MAIN
INPUT
C1
C8
C3 C2
C4
VCC
C5
VCC
C6 C7
C18
VCC
VCC
C17
VCC
R2
T1
4:1
R3
R4
L5
L4
C10
C11
C12
C9
VCC
VCC
C13
VCC
R5
T2
4:1
R6
L6 R8
R7
U1
MAX19985A
Dual, SiGe, High-Linearity, 700MHz to 1000MHz
Downconversion Mixer with LO Buffer/Switch
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 ____________________
23
© 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Pin Configuration/Functional Diagram
MAX19985A
THIN QFN-EP
6mm x 6mm
TOP VIEW (WITH
EXPOSED PAD ON
THE BOTTOM OF THE
PACKAGE)
5
6
4
3
23
22
24
IFDBIAS
IFD+
IFD-
LEXTD
VCC
25
VCC
IFMBIAS
IFM+
IFM-
VCC
LEXTM
LOMBIAS
10 11
VCC
13 14 15 16
3536 34 32 31 30
GND
VCC
GND
GND
LOSEL
GND
GND GND
12
33
721
GND
GND
919
RFDIV LO1
+
VCC
820
TAPDIV
GND
226 GND
TAPMAIN
127 LO2
N.C. N.C.
18
28
VCC
LODBIAS
17
29
RFMAIN
EXPOSED
PAD
Chip Information
PROCESS: SiGe BiCMOS
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages.
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
36 Thin QFN-EP T3666+2 21-0141