19-5959; Rev 0; 6/11
IT
TION K
VALUA
E
BLE
AVAILA
Complete Direct-Conversion L-Band Tuner
General Description
The MAX2121 low-cost, direct-conversion tuner IC is
designed for satellite set-top and VSAT applications.
The device directly converts the satellite signals from
the LNB to baseband using a broadband I/Q downcon-
verter. The operating frequency range extends from
925MHz to 2175MHz.
The device includes an LNA and an RF variable-gain
amplifier, I and Q downconverting mixers, and base-
band lowpass filters and digitally controlled baseband
variable-gain amplifiers. Together, the RF and base-
band variable-gain amplifiers provide more than 80dB
of gain control range.
The device includes fully monolithic VCOs, as well as a
complete fractional-N frequency synthesizer.
Additionally, an on-chip crystal oscillator is provided
along with a buffered output for driving additional tuners
and demodulators. Synthesizer programming and device
configuration are accomplished with a 2-wire serial inter-
face. The IC features a VCO autoselect (VAS) function
that automatically selects the proper VCO. For multituner
applications, the device can be configured to have one
of two 2-wire interface addresses. A low-power standby
mode is available whereupon the signal path is shut
down while leaving the reference oscillator, digital inter-
face, and buffer circuits active, providing a method to
reduce power in single and multituner applications.
The device is the most advanced broadband/VSAT
DBS tuner available. The low noise figure eliminates the
need for an external LNA. A small number of passive
components are needed to form a complete broadband
satellite tuner DVB-S2 RF front-end solution. The tuner
is available in a very small, 5mm x 5mm, 28-pin thin
QFN package.
Features
♦
925MHz to 2175MHz Frequency Range
♦
Monolithic VCO
Low Phase Noise: -97dBc/Hz at 10kHz
No Calibration Required
♦
High Dynamic Range: -75dBm to 0dBm
♦
Integrated LP Filters: 123.75MHz
♦
Single +3.3V ±5% Supply
♦
Low-Power Standby Mode
♦
Address Pin for Multituner Applications
♦
Differential I/Q Interface
♦
I
2
C 2-Wire Serial Interface
♦
Very Small, 5mm x 5mm, 28-Pin TQFN Package
MAX2121
Ordering Information
PART
MAX2121ETI+
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
28 TQFN-EP*
*EP
= Exposed pad.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
Functional Diagram
ADDR
V
CC_BB
QDC+
QDC-
SDA
IDC-
22
21
IDC+
SCL
27
+
V
CC_RF2
1
28
26
25
24
23
INTERFACE LOGIC
AND CONTROL
V
CC_RF1
2
DC OFFSET
CORRECTION
MAX2121
20
IOUT-
GND
3
19
IOUT+
Applications
VSATs
RFIN
4
5
DIV2/DIV4
FREQUENCY
SYNTHESIZER
18
QOUT-
GC1
17
QOUT+
V
CC_LO
6
EP
16
V
CC_DIG
V
CC_VCO
7
8
BYPVCO
9
TUNEVCO
10
GNDTUNE
11
GNDSYN
12
CPOUT
13
V
CC_SYN
14
XTAL
15
REFOUT
________________________________________________________________
Maxim Integrated Products
1
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.
Complete Direct-Conversion L-Band Tuner
MAX2121
ABSOLUTE MAXIMUM RATINGS
V
CC_
to GND .........................................................-0.3V to +3.9V
All Other Pins to GND.................................-0.3V to (V
CC
+ 0.3V)
RF Input Power: RFIN .....................................................+10dBm
BYPVCO, CPOUT, XTAL, REFOUT, IOUT_, QOUT_ , IDC_,
QDC_ to GND Short-Circuit Protection...............................10s
Continuous Power Dissipation (T
A
= +70°C)
TQFN (derate 34.5mW/°C above +70°C) ......................2.75W
Operating Temperature Range .............................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°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.
CAUTION!
ESD SENSITIVE DEVICE
DC ELECTRICAL CHARACTERISTICS
(MAX2121 Evaluation Kit: V
CC_
= +3.13V to +3.47V, f
XTAL
= 27MHz, T
A
= -40°C to +85°C, V
GC1
= +0.5V (max gain), default register
settings except BBG[3:0] = 1011. No input signals at RF, baseband I/Os are open circuited. Typical values measured at V
CC
=
+3.3V, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SUPPLY
Supply Voltage (V
CC_
)
Supply Current
Receive mode, bit STBY = 0
Standby mode, bit STBY = 1
2.4
0.5
50
-50
Maximum gain = 0.5V
0.5
-50
0.4
2.7
+50
2.3
400
0.7 x
V
CC
0.3 x
V
CC
Digital inputs = GND or V
CC
I
SINK
= 1mA (Note 2)
±0.1
±1
0.4
3.13
3.3
148
3
3.47
200
V
mA
CONDITIONS
MIN
TYP
MAX
UNITS
ADDRESS SELECT INPUT (ADDR)
Digital Input-Voltage High, V
IH
Digital Input-Voltage Low, V
IL
Digital Input-Current High, I
IH
Digital Input-Current Low, I
IL
ANALOG GAIN-CONTROL INPUT (GC1)
Input Voltage Range
Input Bias Current
VCO TUNING VOLTAGE INPUT (TUNEVCO)
Input Voltage Range
2-WIRE SERIAL INPUTS (SCL, SDA)
Clock Frequency
Input Logic-Level High
Input Logic-Level Low
Input Leakage Current
2-WIRE SERIAL OUTPUT (SDA)
Output Logic-Level Low
V
kHz
V
V
μA
V
V
μA
V
V
μA
μA
2
_______________________________________________________________________________________
Complete Direct-Conversion L-Band Tuner
AC ELECTRICAL CHARACTERISTICS
(MAX2121 Evaluation Kit: V
CC
= +3.13V to +3.47V, T
A
= -40°C to +85°C, default register settings except BBG[3:0] = 1111. Typical
values measured at V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
MAIN SIGNAL PATH PERFORMANCE
Minimum Gain
Gain Flatness
Input Frequency Range
RF Gain-Control Range (GC1)
Baseband Gain-Control Range
In-Band Input IP3
Out-of-Band Input IP3
Input IP2
f
IN
= 2175MHz
925MHz to 2175MHz (Note 2)
(Note 3)
0.5V < V
GC1
< 2.7V
Bits BBG[3:0] = 1111 to 0000
(Note 4)
(Note 5)
(Note 6)
V
GC1
is set to 0.5V (maximum RF gain) and BBG[3:0]
is adjusted to give a 1V
P-P
baseband output level for a
-75dBm CW input tone at 1500MHz
Starting with the same BBG[3:0] setting as above,
V
GC1
is adjusted to back off RF gain by 10dB (Note 2)
Minimum RF Input Return Loss
Nominal Output Voltage Swing
I/Q Amplitude Imbalance
I/Q Quadrature Phase Imbalance
Single-Ended I/Q Output
Impedance
Output 1dB Compression Voltage
Baseband Highpass -3dB
Frequency Corner
Filter Bandwidth (-3dB)
Rejection Ratio
Group Delay
3dB Bandwidth Tolerance
FREQUENCY SYNTHESIZER
RF-Divider Frequency Range
RF-Divider Range (N)
Reference-Divider Frequency
Range
Reference-Divider Range (R)
Phase-Detector Comparison
Frequency
925
19
12
1
12
2175
251
30
1
30
MHz
MHz
MHz
At 247.5MHz
Up to 0.5dB bandwidth
925MHz < f
RF
< 2175MHz, in 75
R
LOAD
= 200 //5pF
Measured at 500kHz
Measured at 500kHz
Real Z
O
, from 1MHz to 140MHz
Differential
47nF capacitors at IDC_, QDC_
24
3
400
V
P-P
Hz
system
0.5
BASEBAND OUTPUT CHARACTERISTICS
1
±1
3.5
V
P-P
dB
Degrees
925
65
11.5
73
13.5
+2
+15
+40
8
dB
9
12
12
dB
72
78
4
6
2175
dB
dB
MHz
dB
dB
dBm
dBm
dBm
CONDITIONS
MIN
TYP
MAX
UNITS
MAX2121
Noise Figure
BASEBAND LOWPASS FILTERS (5th-Order Butterworth with 1st-Order Group Delay Compensation)
123.75
31
1.0
±10
MHz
dB
ns
%
_______________________________________________________________________________________
3
Complete Direct-Conversion L-Band Tuner
MAX2121
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2121 Evaluation Kit: V
CC
= +3.13V to +3.47V, T
A
= -40°C to +85°C, default register settings except BBG[3:0] = 1111. Typical
values measured at V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Guaranteed LO Frequency Range
f
OFFSET
= 10kHz
LO Phase Noise
f
OFFSET
= 100kHz
f
OFFSET
= 1MHz
XTAL/REFERENCE OSCILLATOR INPUT AND OUTPUT BUFFER
XTAL Oscillator Frequency
Range f
XTAL
Input Overdrive Level
XTAL Output-Buffer Divider
Range
XTAL Output Voltage Swing
XTAL Output Duty Cycle
12MHz to 30MHz, C
LOAD
= 10pF
Parallel-resonance-mode crystal (Note 7)
AC-coupled sine-wave input
12
0.5
1
1
1.5
50
1
30
2.0
8
2
V
P-P
%
MHz
V
P-P
CONDITIONS
MIN
925
-97
-100
-122
dBc/Hz
TYP
MAX
2175
UNITS
MHz
VOLTAGE-CONTROLLED OSCILLATOR AND LO GENERATION
Note 1:
Min/max values are production tested at T
A
= +25°C. Min/max limits at T
A
= -40°C and T
A
= +85°C are guaranteed by
design and characterization.
Note 2:
Guaranteed by design and characterization at T
A
= +25°C.
Note 3:
Input gain range specifications met over this band.
Note 4:
In-band IIP3 test conditions: GC1 set to provide the nominal baseband output drive when mixing down a -23dBm tone at
2175MHz to 5MHz baseband (f
LO
= 2170MHz). Baseband gain is set to its default value (BBG[3:0] = 1011). Two tones at
-26dBm each are applied at 1919MHz and 1663MHz. The IM3 tone at 3MHz is measured at baseband, but is referred to the
RF input.
Note 5:
Out-of-band IIP3 test conditions: GC1 set to provide nominal baseband output drive when mixing down a -23dBm tone at
2175MHz to 5MHz baseband (f
LO
= 2170MHz). Baseband gain is set to its default value (BBG[3:0] = 1011). Two tones at
-20dBm each are applied at 1919MHz and 1663MHz. The IM3 tone at 5MHz is measured at baseband, but is referred to the
RF input.
Note 6:
Input IP2 test conditions: GC1 set to provide nominal baseband output drive when mixing down a -23dBm tone at 2175MHz
to 5MHz baseband (f
LO
= 2170MHz). Baseband gain is set to its default value (BBG[3:0] = 1011). Two tones at -20dBm
each are applied at 925MHz and 1250MHz. The IM2 tone at 5MHz is measured at baseband, but is referred to the RF input.
Note 7:
See Table 16 for crystal ESR requirements.
4
_______________________________________________________________________________________
Complete Direct-Conversion L-Band Tuner
Typical Operating Characteristics
(MAX2121 Evaluation Kit: V
CC
= +3.3V, T
A
= +25°C, baseband output frequency = 5MHz, V
GC1
= +1.2V, default register settings
except BBG[3:0] = 1011, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2121 toc01
MAX2121
STANDBY SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX2121 toc02
HD3 vs. V
OUT
BASEBAND 3RD-ORDER HARMONIC (dBc)
-15
-20
-25
-30
-35
-40
-45
-50
-55
-60
1.0
1.5
2.0
V
OUT
(V
P-P
)
2.5
3.0
MAX2121 toc03
175
170
165
SUPPLY CURRENT (mA)
160
155
150
145
140
135
130
125
3.1
3.2
3.3
3.4
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
3.0
STANDBY SUPPLY CURRENT (mA)
-10
2.5
T
A
= +85°C
2.0
1.5
T
A
= -40°C
1.0
3.5
3.1
3.2
3.3
3.4
3.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
QUADRATURE PHASE ERROR
vs. LO FREQUENCY
MAX2121 toc04
QUADRATURE MAGNITUDE MATCHING
vs. LO FREQUENCY
MAX2121 toc05
QUADRATURE PHASE ERROR
vs. BASEBAND FREQUENCY
f
LO
= 1425MHz
T
A
= -40°C
2.5
T
A
= +85°C
2.0
1.5
1.0
0.5
0
T
A
= +25°C
MAX2121 toc06
3.5
QUADRATURE PHASE ERROR (DEG)
3.0
2.5
2.0
1.5
1.0
0.5
0
QUADRATURE MAGNITUDE MATCHING (dB)
f
BASEBAND
= 50MHz
1.0
f
BASEBAND
= 50MHz
3.5
QUADRATURE PHASE ERROR (DEG)
3.0
0.8
T
A
= +25°C
T
A
= -40°C
0.6
0.4
T
A
= +85°C
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
0.2
0
900
1150
1400
1650
1900
2150
900
1150
1400
1650
1900
2150
LO FREQUENCY (MHz)
LO FREQUENCY (MHz)
0.1
1
10
100
BASEBAND FREQUENCY (MHz)
QUADRATURE MAGNITUDE MATCHING
vs. BASEBAND FREQUENCY
MAX2121 toc07
BASEBAND FILTER FREQUENCY RESPONSE
0
-5
-10
-15
-20
-25
-30
-35
-40
-45
-50
-55
-60
-65
0
100
200
300
400
BASEBAND FREQUENCY (MHz)
MAX2121 toc08
BASEBAND FILTER FREQUENCY RESPONSE
0
BASEBAND OUTPUT LEVEL (dB)
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
T
A
= +25°C
MAX2121 toc09
1.0
QUADRATURE MAGNITUDE MATCHING (dB)
f
LO
= 1425MHz
1
0.8
T
A
= +25°C
0.6
0.4
T
A
= +85°C
T
A
= -40°C
0
0.1
1
10
100
BASEBAND FREQUENCY (MHz)
0.2
BASEBAND OUTPUT LEVEL (dB)
500
0
25
50
75
100
125
150
BASEBAND FREQUENCY (MHz)
_______________________________________________________________________________________
5
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