MAXIM MAX2121 User Manual

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 downcon­verter. 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 base­band lowpass filters and digitally controlled baseband
variable-gain amplifiers. Together, the RF and base­band 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 inter­face. 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 inter­face, 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.

Applications

VSATs

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

Complete Direct-Conversion L-Band Tuner

________________________________________________________________

Maxim Integrated Products

1

Functional Diagram

Ordering Information

19-5959; Rev 0; 6/11

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.

*

EP = Exposed pad.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

EVALUATION KIT

AVAILABLE

PART TEMP RANGE PIN-PACKAGE

MAX2121ETI+ -40°C to +85°C 28 TQFN-EP*

CC_BB

V

SDA

26 24 23

MAX2121

FREQUENCY

SYNTHESIZER

QDC-

25

DC OFFSET

CORRECTION

QDC+

IDC-

21

20

19

18

17

16

V

CC_RF2

V

CC_RF1

V

GND

RFIN

GC1

CC_LO

+

1

2

3

4

5

6

ADDR

27

28

INTERFACE LOGIC

AND CONTROL

DIV2/DIV4

EP

SCL

IDC+

IOUT-

IOUT+

QOUT-

QOUT+

V

CC_DIG

V

CC_VCO

XTAL

15

REFOUT

7

10 12

8

BYPVCO

9

TUNEVCO

11 132214

CPOUT

GNDSYN

GNDTUNE

CC_SYN

V

MAX2121

Complete Direct-Conversion L-Band Tuner

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(MAX2121 Evaluation Kit: V

CC_

= +3.13V to +3.47V, f

XTAL

= 27MHz, TA= -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)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

V

CC_

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

CAUTION! ESD SENSITIVE DEVICE

SUPPLY

Supply Voltage (V

Supply Current

ADDRESS SELECT INPUT (ADDR)

Digital Input-Voltage High, VIH 2.4 V

Digital Input-Voltage Low, VIL 0.5 V

Digital Input-Current High, IIH 50 μA

Digital Input-Current Low, IIL -50 μA

ANALOG GAIN-CONTROL INPUT (GC1)

Input Voltage Range Max imum gain = 0.5V 0.5 2.7 V

Input Bias Current -50 +50 μA

VCO TUNING VOLTAGE INPUT (TUNEVCO)

Input Voltage Range 0.4 2.3 V

2-WIRE SERIAL INPUTS (SCL, SDA)

Cloc k Frequenc y 400 kHz

Input Logic-Level High

Input Logic-Level Low

Input Leakage Current Digital inputs = GND or VCC ±0.1 ±1 μA

2-WIRE SERIAL OUTPUT (SDA)

Output Logic-Level Low I

PARAMETER CONDITIONS MIN TYP MAX UNITS

) 3.13 3.3 3.47 V

CC_

Receive mode, bit STBY = 0 148 200

Standby mode, bit STBY = 1 3

SINK

= 1mA (Note 2) 0.4 V

0.7 x
V

CC

V

0.3 x
V

CC

mA

V

MAX2121

Complete Direct-Conversion L-Band Tuner

_______________________________________________________________________________________ 3

AC ELECTRICAL CHARACTERISTICS

(MAX2121 Evaluation Kit: V

CC

= +3.13V to +3.47V, TA= -40°C to +85°C, default register settings except BBG[3:0] = 1111. Typical

values measured at V

CC

= +3.3V, TA= +25°C, unless otherwise noted.) (Note 1)

PARAMETER CONDITIONS MIN TYP MAX UNITS

MAIN SIGNAL PATH PERFORMANCE

Minimum Gain fIN = 2175MHz 72 78 dB

Gain Flatness 925MHz to 2175MHz (Note 2) 4 6 dB

Input Frequency Range (Note 3) 925 2175 MHz

RF Gain-Control Range (GC1) 0.5V < V

Baseband Gain-Control Range Bits BBG[3:0] = 1111 to 0000 11.5 13.5 dB

In-Band Input IP3 (Note 4) +2 dBm

Out-of-Band Input IP3 (Note 5) +15 dBm

Input IP2 (Note 6) +40 dBm

Noise Figure

Minimum RF Input Return Loss 925MHz < f

BASEBAND OUTPUT CHARACTERISTICS

Nominal Output Voltage Swing R

I/Q Amplitude Imbalance Measured at 500kH z ±1 dB

I/Q Quadrature Phase Imbalance Measured at 500kH z 3.5 Degrees

Single-Ended I/Q Output
Impedance

Output 1dB Compression Voltage Differential 3 V

Baseband Highpass -3dB
Frequency Corner

BASEBAND LOWPASS FILTERS (5th-Order Butterworth with 1st-Order Group Delay Compensation)

Filter Bandwidth (-3dB) 123.75 MHz

Rejection Ratio At 247.5MHz 31 dB

Group Delay Up to 0.5dB bandwidth 1.0 ns

3dB Bandwidth Tolerance ±10 %

FREQUENCY SYNTHESIZER

RF-Divider Frequency Range 925 2175 MHz

RF-Divider Range (N) 19 251

Reference-Divider Frequency
Range

Reference-Di vider Range (R) 1 1

Phase-Detector Comparison
Frequency

< 2.7V 65 73 dB

GC1

V

is set to 0.5V (maximum RF gain) and BBG[3:0]

GC1

is ad justed to give a 1V

-75dBm CW input tone at 1500MHz

Starting with the same BBG[3:0] setting as above,
V

is adjusted to back off RF gain by 10dB (Note 2)

GC1

< 2175MHz, in 75 system 12 dB

RF

= 200//5pF 0.5 1 V

LOAD

Real Z

47nF capacitors at IDC_, QDC_ 400 Hz

12 30 MHz

12 30 MHz

, from 1MH z to 140MHz 24 

O

baseband output leve l for a

P-P

8

9 12

dB

P-P

P-P

MAX2121

Complete Direct-Conversion L-Band Tuner

4 _______________________________________________________________________________________

AC ELECTRICAL CHARACTERISTICS (continued)

(MAX2121 Evaluation Kit: V

CC

= +3.13V to +3.47V, TA= -40°C to +85°C, default register settings except BBG[3:0] = 1111. Typical

values measured at V

CC

= +3.3V, TA= +25°C, unless otherwise noted.) (Note 1)

Note 1: Min/max values are production tested at TA= +25°C. Min/max limits at TA= -40°C and TA= +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.

PARAMETER CONDITIONS MIN TYP MAX UNITS

VOLTAGE-CONTROLLED OSCILLATOR AND LO GENERATION

Guaranteed LO Frequency Range 925 2175 MHz

LO Phase Noise

XTAL/REFERENCE OSCILLATOR INPUT AND OUTPUT BUFFER

XTAL Oscillator Frequency
Range f

XTAL

Input Overdrive Leve l AC-coupled sine-wave input 0.5 1 2.0 V

XTAL Output-Buffer Divider
Range

XTAL Output Voltage Swing 12MHz to 30MHz, C

XTAL Output Duty Cycle 50 %

f

= 10kHz -97

OFFSET

f

= 100kHz -100

OFFSET

= 1MHz -122

f

OFFSET

Paralle l-resonance-mode crystal (Note 7) 12 30 MHz

1 8

= 10pF 1 1.5 2 V

LOAD

dBc/Hz

P-P

P-P

MAX2121

Complete Direct-Conversion L-Band Tuner

_______________________________________________________________________________________

5

Typical Operating Characteristics

(MAX2121 Evaluation Kit: V

CC

= +3.3V, TA= +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

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

3.43.33.2

130

135

140

145

150

155

160

165

170

175

125

3.1 3.5

TA = +85°C

TA = +25°C

TA = -40°C

STANDBY SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX2121 toc02

SUPPLY VOLTAGE (V)

STANDBY SUPPLY CURRENT (mA)

3.43.33.2

1.5

2.0

2.5

3.0

1.0

3.1 3.5

TA = +85°C

TA = -40°C

HD3 vs. V

OUT

MAX2121 toc03

V

OUT

(V

P-P

)

BASEBAND 3RD-ORDER HARMONIC (dBc)

2.52.01.5

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10

-60

1.0 3.0

QUADRATURE PHASE ERROR

vs. LO FREQUENCY

MAX2121 toc04

LO FREQUENCY (MHz)

QUADRATURE PHASE ERROR (DEG)

1900165014001150

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0

900 2150

f

BASEBAND

= 50MHz

TA = +85°C

TA = +25°C

TA = -40°C

QUADRATURE MAGNITUDE MATCHING

vs. LO FREQUENCY

MAX2121 toc05

LO FREQUENCY (MHz)

QUADRATURE MAGNITUDE MATCHING (dB)

1900165014001150

0.2

0.4

0.6

0.8

1.0

0

900 2150

f

BASEBAND

= 50MHz

TA = +85°C

TA = +25°C

TA = -40°C

QUADRATURE PHASE ERROR

vs. BASEBAND FREQUENCY

MAX2121 toc06

BASEBAND FREQUENCY (MHz)

QUADRATURE PHASE ERROR (DEG)

101

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0

0.1 100

fLO = 1425MHz

TA = +85°C

TA = +25°C

TA = -40°C

QUADRATURE MAGNITUDE MATCHING

vs. BASEBAND FREQUENCY

MAX2121 toc07

BASEBAND FREQUENCY (MHz)

QUADRATURE MAGNITUDE MATCHING (dB)

101

0.2

0.4

0.6

0.8

1.0

0

0.1 100

fLO = 1425MHz

TA = +85°C

TA = +25°C

TA = -40°C

BASEBAND FILTER FREQUENCY RESPONSE

MAX2121 toc08

BASEBAND FREQUENCY (MHz)

BASEBAND OUTPUT LEVEL (dB)

400300200100

-60

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

-65
0 500

BASEBAND FILTER FREQUENCY RESPONSE

MAX2121 toc09

BASEBAND FREQUENCY (MHz)

BASEBAND OUTPUT LEVEL (dB)

125100755025

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

1

-10
0 150

TA = +25°C

MAX2121

Complete Direct-Conversion L-Band Tuner

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(MAX2121 Evaluation Kit: V

CC

= +3.3V, TA= +25°C, baseband output frequency = 5MHz, V

GC1

= +1.2V, default register settings

except BBG[3:0] = 1011, unless otherwise noted.)

BASEBAND FILTER 3dB FREQUENCY

vs. TEMPERATURE

MAX2121 toc10

TEMPERATURE (°C)

BASEBAND GAIN ERROR AT f-3dB (dB)

8060-20 0 20 40

-0.75

-0.50

-0.25

0

0.25

0.50

0.75

1.00

-1.00

-40

NORMALIZED AT TA = +25°C

BASEBAND FILTER HIGHPASS

FREQUENCY RESPONSE

MAX2121 toc11

BASEBAND FREQUENCY (Hz)

BASEBAND OUTPUT LEVEL (dB)

1000

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

-10
100 10,000

VOLTAGE GAIN vs. V

GC1

MAX2121 toc12

V

GC1

(V)

VOLTAGE GAIN (dB)

2.52.00.5 1.0 1.5

10

20

30

40

50

60

70

80

0

0 3.0

BBG[3:0] = 1111

NOISE FIGURE vs. LO FREQUENCY

(T

A

= +25°C)

MAX2121 toc13

LO FREQUENCY (MHz)

NOISE FIGURE (dB)

190016501150 1400

7.5

8.0

8.5

9.0

10.0

9.5

10.5

11.0

7.0
900 2150

ADJUST BBG[3:0] FOR 1V

P-P

BASEBAND

OUTPUT WITH PIN = -75dBm AND V

GC1

= 0.5V

10dB BACKED OFF GAIN

INPUT RETURN LOSS vs. FREQUENCY

MAX2121 toc14

FREQUENCY (MHz)

INPUT RETURN LOSS (dB)

202518001350 15751125

-20

-15

-10

-5

0

-25
900 2250

V

GC1

= 2.7V

V

GC1

= 0.5V

PHASE NOISE AT 10kHz OFFSET vs.

CHANNEL FREQUENCY

CHANNEL FREQUENCY (MHz)

PHASE NOISE AT 10kHz OFFSET (dBc/Hz)

MAX2121 toc15

925 1115 1305 1495 1685 1875 2065 2255

-105

-100

-95

-90

PHASE NOISE vs. OFFSET FREQUENCY

MAX2121 toc16

OFFSET FREQUENCY (Hz)

PHASE NOISE (dBc/Hz)

1.0E+051.0E+04

-120

-110

-100

-90

-130

1.0E+03 1.0E+06

fLO = 1800MHz

LO LEAKAGE vs. LO FREQUENCY

LO FREQUENCY (MHz)

LO LEAKAGE (dBm)

MAX2121 toc17

925 1175 1425 1675 1925 2175

-90

-85

-80

-75

-70

MEASURED AT RF INPUT

VCO: KV vs. VTUNE

VTUNE (V)

KV (MHz/V)

MAX2121 toc18

0 0.5 1.0 1.5 2.0 2.5 3.0

0

50

100

150

200

250

300

350

400

450

SUB-BAND 23

SUB-BAND 12

SUB-BAND 0