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19-1256; Rev 2; 10/98
UAL IT MAN TION K SHEET VALUA E TA WS DA FOLLO
Direct-Conversion Tuner ICs for Digital DBS Applications
____________________________Features
o Low-Cost Bipolar Design, Lowest Cost Architecture o Operate from a Single +5V Supply o 950MHz to 2150MHz Input Frequency Range* o On-Chip Quadrature Generator, Dual-Modulus Prescaler (/64, /65) o Input Levels -69dBm to -19dBm per Carrier (MAX2102) -60dBm to -19dBm per Carrier (MAX2105) o Over 50dB AGC Control Range (MAX2102) o Noise Figure = 13.2dB (MAX2102); IP3 = 6.5dBm (at 1450MHz) o Automatic Baseband Offset Correction o Easy Interface to MAX1002/MAX1003 Dual ADC and Popular Baseband ICs
General Description
The MAX2102/MAX2105 are low-cost direct-conversion tuner ICs designed for use in digital direct-broadcast satellite (DBS) television set-top box units. The direct-conversion architecture reduces system cost compared to devices with IF-based architectures. The MAX2102/MAX2105 directly tune L-band signals to baseband using a broadband I/Q downconverter. Operating frequency range spans from at least 950MHz to 2150MHz. The ICs include a low-noise amplifier (LNA) with automatic gain control (AGC), two downconverter mixers, an oscillator buffer with 90 quadrature generator and prescaler, and baseband amplifiers. The MAX2102 features an AGC range of 50dB, allowing input power levels as low as -69dBm. The MAX2105 has a reduced AGC range of 41dB and accepts input power levels down to -60dBm. The reduced AGC range of the MAX2105 allows the use of a high-gain external LNA to achieve a lower system noise figure (NF).
MAX2102/MAX2105
________________________Applications
DBS Tuners DVB-Compliant DBS Tuners Cellular Base Stations Wireless Local Loop Broadband Systems LMDS
PART MAX2102CWI MAX2105CWI
Ordering Information
TEMP. RANGE 0C to +70C 0C to +70C PIN-PACKAGE 28 SO 28 SO
Functional Diagram
VCC 14 QOUT 13 GND 12 GND 11 AGC 10 GND 9 RFIN 8 RFIN 7 VCC 6 GND 5 VCC 4 GND 3 IOUT 2 VCC 1
Q
I
MAX2102 MAX2105
OFFSET CORRECTION 15 QDC 16 QDC 17 IDC 18 IDC 19 GND 20
90 0
/64, /65
21 LO
22 LO
23 VCC
24 GND
25 PSGND
26 PSOUT
27 MOD
28 VCC
VCC
Patents pending
*Contact factory for MAX2102/MAX2105 versions with expanded frequency range. ________________________________________________________________ Maxim Integrated Products 1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769.
Direct-Conversion Tuner ICs for Digital DBS Applications MAX2102/MAX2105
ABSOLUTE MAXIMUM RATINGS
VCC to GND ..............................................................-0.5V to +7V RFIN to RFIN ..........................................................................2V LO to LO ................................................................................2V AGC, MOD, RFIN, RFIN, LO, LO to GND.....-0.5V to (VCC + 0.5V) AGC Current. ....................................................................30mA IDC to IDC, QDC to QDC.......................................................2V IOUT or QOUT to GND Short-Circuit Duration ...................10sec PSOUT to GND Short-Circuit Duration.................................None IDC, IDC, QDC, QDC to GND ....................-0.5V to (VCC + 0.5V) Continuous Power Dissipation (TA = +70C) SO (derate 12.5mW/C above +70C) ..........................1.025W Operating Temperature Range...............................0C to +70C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10sec) .............................+300C
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
(VCC = +4.75V to +5.25V; GND = 0V; PSGND = GND; AGC = 1.3V; MOD = 0.8V; PRFIN = OFF, fLO = 1450.125MHz; PLO = -15dBm; IOUT, QOUT = open; TA = 0C to +70C; unless otherwise noted.) PARAMETER SUPPLY Operating Supply Voltage Range Quiescent Supply Current CONTROL INPUTS, PRESCALER MOD Input Low Level MOD Input High Level MOD Input Bias Current AGC Input Bias Current AGC Input Bias Current IOUT, QOUT Common-Mode Voltage 0V VMOD VCC MAX2102 MAX2105 0.5V VAGC 4V 1V VAGC 4V 2.0 -80 -250 -180 2.2 10 180 180 2.6 0.8 V V A A V 4.75 150 5.25 195 V mA CONDITIONS MIN TYP MAX UNITS
AC ELECTRICAL CHARACTERISTICS
(MAX2102 EV kit circuit (Figure 1); V CC = +5V; PSGND = open; MOD = GND; f RFIN = 2150MHz; P RFIN = -19dBm; f LO = 2150.125MHz; PLO = -15dBm driven single-ended into LO; AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p; IOUT, QOUT drive AC-coupled 100 loads; 2k from PSOUT to GND; TA = +25C; unless otherwise noted.) PARAMETER RF FRONT END RFIN Carrier Frequency Range RFIN Maximum Single-Carrier Input Power (Note 1) Refers to single-carrier power generating VIOUT = VQOUT = 0.5Vp-p, 950MHz < fRFIN < 2150MHz, 950MHz < fLO < 2150MHz (Note 2) Refers to single-carrier power generating VIOUT = VQOUT = 0.5Vp-p, 950MHz < fRFIN < 2150MHz, 950MHz < fLO < 2150MHz (Note 2) 0.5V VAGC 4V 1V VAGC 4V MAX2102 MAX2105 MAX2102 MAX2105 50 41 950 2150 MHz CONDITIONS MIN TYP MAX UNITS
-19
dBm
RFIN Minimum Single-Carrier Input Power
-69 dBm -60 dB
AGC Range
2
_______________________________________________________________________________________
Direct-Conversion Tuner ICs for Digital DBS Applications
AC ELECTRICAL CHARACTERISTICS
(MAX2102 EV kit circuit (Figure 1); V CC = +5V; PSGND = open; MOD = GND; f RFIN = 2150MHz; P RFIN = -19dBm; f LO = 2150.125MHz; PLO = -15dBm driven single-ended into LO; AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p; IOUT, QOUT drive AC-coupled 100 loads; 2k from PSOUT to GND; TA = +25C; unless otherwise noted.) PARAMETER CONDITIONS PRFIN = -19dBm per tone, AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p per tone, f1RFIN = 1448.1MHz, f2RFIN = 1449MHz, fLO = 1451MHz PRFIN = -19dBm per tone, AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p per tone, f1RFIN = 1200MHz, f2RFIN = 2150MHz, fLO = 951MHz fRFIN = 1441MHz, fLO = 1451MHz PRFIN = -69dBm PRFIN = -60dBm PRFIN = -69dBm Noise Figure PRFIN = -60dBm fRFIN = 2141MHz, fLO = 2151MHz MAX2102 MAX2105 MAX2102 MAX2105 MIN TYP MAX UNITS
MAX2102/MAX2105
RFIN Input Third-Order Intercept
6.5
dBm
RFIN Input Second-Order Intercept
15.1
dBm
13.2 15.7 12.9 15.5 11.2 11.5 -0.5 dB/dB -0.7 2.3:1 dB
AGC = 4V, MAX2102 PRFIN set via servo loop for VIOUT = MAX2105 VQOUT = 0.5Vp-p MAX2102 MAX2105
Defined as NF/Gain; for AGC range, Maximum Noise-Figure Variation with defined as single-carrier power range AGC Gain Setting of -69dBm to -59dBm (MAX2102) or -60dBm to -50dBm (MAX2105) RFIN Worst-Case VSWR across Band fRFIN = 950MHz to 2150MHz, 50 source
Maximum Power of Spurious Downconversion Products
950MHz < fRFIN < 2150MHz, 950MHz < fLO < 2150MHz. Dominated by LO second-harmonic power causing downconversion of unwanted channel. Test conditions: fLO = 1075.5MHz, fRFIN = 2150MHz, PRFIN = -69dBm (MAX2102) or -60dBm (MAX2105) PLO = -15dBm, 950MHz < fLO < 2150MHz (Note 3)
-32.3
dBc
-49 dBm -54
LO Leakage at RFIN
PLO = -15dBm, P LO = -15dBm (differentially driven), 950MHz < fLO < 2150MHz (Note 3)
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3
Direct-Conversion Tuner ICs for Digital DBS Applications MAX2102/MAX2105
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2102 EV kit circuit (Figure 1); V CC = +5V; PSGND = open; MOD = GND; f RFIN = 2150MHz; P RFIN = -19dBm; f LO = 2150.125MHz; PLO = -15dBm driven single-ended into LO; AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p; IOUT, QOUT drive AC-coupled 100 loads; 2k from PSOUT to GND; TA = +25C; unless otherwise noted.) PARAMETER LO Input Frequency Range LO Input Worst-Case VSWR over Band (Note 1) fLO = 950MHz to 2150MHz, 50 source into MAX2102 EV kit match circuit (Note 4) LO Input Power Level RFIN to LO Input Isolation IOUT, QOUT Phase Imbalance Worst-Case Additional Phase Imbalance Over Temperature IOUT, QOUT Amplitude Imbalance Refers to power level driven into LO, LO (differentially driven) (Notes 2, 4) (Notes 2, 5) 950MHz < fRFIN < 2150MHz; 950MHz < fLO < 2150MHz; PRFIN = -40dBm; fIOUT, fQOUT = 125kHz (Note 2) TA = +25C to +70C (Notes 2 and 6) TA = +25C to +0C (Note 2) 950MHz < fRFIN < 2150MHz; 950MHz < fLO < 2150MHz; PRFIN = -40dBm; fIOUT, fQOUT = 125kHz (Note 2) TA = 0C to +70C (Note 2) 2k || 10pF load PSOUT load = 2k || 5pF (Note 3) PRFIN = -50dBm; AGC = 4V, VCC = 5.0V At -3dB attenuation 1kHz < (fIOUT, fQOUT) < 25MHz, 950MHz < fRFIN < 2150MHz, 950MHz < fLO < 2150MHz (Notes 3, 7, 8) 1kHz < (fIOUT, fQOUT) < 25MHz, 950MHz < fRFIN < 2150MHz, 950MHz < fLO < 2150MHz (Notes 3, 7, 8) MOD = low MOD = high 64 65 0.8 35 2.7 94 0.45 0.85 65 -0.1 -0.07 -15 -15 28 3 0.6 1 0.5 64 65 Vp-p % Vp-p MHz dB dB degrees CONDITIONS MIN 950 1.75:1 -5 dBm TYP MAX 2150 UNITS MHz
OSCILLATOR BUFFER, QUADRATURE GENERATOR, PRESCALER
degrees
dB
Prescaler Divide Ratio Prescaler Output Swing at PSOUT Prescaler Duty Cycle at PSOUT BASEBAND AC CHARACTERISTICS IOUT, QOUT Clipping Level Baseband Bandwidth (at IOUT, QOUT) Baseband Gain Ripple (at IOUT, QOUT) Baseband Group Delay Ripple (at IOUT, QOUT)
0.45
ns
4
_______________________________________________________________________________________
Direct-Conversion Tuner ICs for Digital DBS Applications
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2102 EV kit circuit (Figure 1); V CC = +5V; PSGND = open; MOD = GND; f RFIN = 2150MHz; P RFIN = -19dBm; f LO = 2150.125MHz; PLO = -15dBm driven single-ended into LO; AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p; IOUT, QOUT drive AC-coupled 100 loads; 2k from PSOUT to GND; TA = +25C; unless otherwise noted.) PARAMETER IOUT, QOUT Output Impedance Maximum IOUT to QOUT Output Impedance Difference Power-Supply Ripple Rejection (measured at IOUT, QOUT) (Note 3) (Note 3) VCC = 5V + 50mVp-p at 300kHz. Amplitude of 300kHz relative to 500mVp-p measured at IOUT, QOUT. Measured using MAX2102 EV kit. CONDITIONS MIN TYP 4.7 1 MAX 10 UNITS
MAX2102/MAX2105
32
dB
Note 1: All specifications with guaranteed min/max limits are met within this frequency range. Contact factory for MAX2102/MAX2105 versions with expanded frequency range. Note 2: Guaranteed by production test and/or design and characterization. Note 3: Guaranteed by design and characterization. Note 4: IOUT, QOUT Phase and Amplitude Imbalance specifications are met within this LO power range. Note 5: Tested under two conditions: 1) Normal test: PRFIN = -20dBm, and 2) Overdrive test: PRFIN = -5dBm but AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p for PRFIN = -30dBm. Note 6: Negative numbers (-0.1) indicate improvement in quadrature accuracy with increasing temperature. Note 7: Includes contribution from front-end gain tilt and delay variations produced by varying fRFIN by 30MHz. Note 8: 1kHz minimum frequency determined by 0.22F offset-correction capacitors. Different value capacitors yield proportionally different low-frequency cutoffs. Group delay at low frequencies will also be affected. See Applications Information section.
__________________________________________Typical Operating Characteristics
(MAX2102 EV kit circuit (Figure 1), VCC = 5V, PSGND = open, MOD = GND, fRFIN = 2150MHz, PRFIN = -19dBm, fLO = 2150.125MHz, PLO = -15dBm driven single-ended into LO, AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p, IOUT, QOUT drive AC-coupled 100 loads, 2k from PSOUT to GND, TA = +25C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2102/05-01
MAX2102 AGC RANGE vs. FREQUENCY
SINGLE-CARRIER POWER FOR 0.5Vp-p BASEBAND LEVEL (dBm) SINGLE CARRIER POWER FOR 0.5Vp-p BASEBAND LEVEL (dBm) -10 -20 -30 -40 -50 -60 -70 -80 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 RFIN FREQUENCY (GHz) TA = +70C TA = +25C TA = 0C AGC = 4V
MAX2102/05-02
MAX2105 AGC RANGE vs. FREQUENCY
-10 -20 -30 -40 -50 -60 AGC = 4V -70 -80 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 RFIN FREQUENCY (GHz) TA = 0C TA = +25C TA = +70C TA = 0C AGC = 1V TA = +25C TA = +70C
MAX2102/05-01insert
180 170 SUPPLY CURRENT (mA) 160 150 140 130 120 4.75 4.85 5.00 5.15 TA = +25C PSGND = GND (PRESCALER ENABLED) TA = +70C
0 AGC = 1V TA = +70C TA = +25C TA = 0C AGC RANGE
0
TA = 0C
5.25
SUPPLY VOLTAGE (V)
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5
Direct-Conversion Tuner ICs for Digital DBS Applications MAX2102/MAX2105
Typical Operating Characteristics (continued)
(MAX2102 EV kit circuit (Figure 1), VCC = 5V, PSGND = open, MOD = GND, fRFIN = 2150MHz, PRFIN = -19dBm, fLO = 2150.125MHz, PLO = -15dBm driven single-ended into LO, AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p, IOUT, QOUT drive AC-coupled 100 loads, 2k from PSOUT to GND, TA = +25C, unless otherwise noted.)
MAX2102 CARRIER LEVEL vs. AGC VOLTAGE
SINGLE-CARRIER POWER FOR 0.5Vp-p BASEBAND LEVEL (dBm) SINGLE-CARRIER INPUT LEVEL FOR 0.5Vp-p BASEBAND LEVEL (dBm) AGC SET FOR IOUT QOUT = 0.5Vp-p -20
MAX2102/05-03
MAX2105 CARRIER LEVEL vs. AGC VOLTAGE
MAX2102/05-02insert
MAX2102 NOISE FIGURE vs. FREQUENCY
AGC SET FOR PRFIN = -69dBm TA = +70C 14.0 13.5 13.0 TA = 0C 12.5 TA = +25C
MAX2102/05-04
0
0 -10 -20 -30 -40 -50 -60 -70 TA = 0C 1.6 2.0 2.4 2.8 3.2 3.6 TA = +70C TA = +25C AGC SET FOR IOUT, QOUT = 0.5Vp-p
15.0 14.5 NOISE FIGURE (dB)
-40
TA = +70C TA = +25C
-60 TA = 0C -80 1 2 3 4 AGC VOLTAGE (V)
12.0 4.0 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 LO FREQUENCY (GHz)
AGC VOLTAGE (V)
MAX2105 NOISE FIGURE vs. FREQUENCY
MAX2102/05-03insert
MAX2102 NOISE FIGURE vs. INPUT CARRIER LEVEL
MAX2102/05-05
MAX2105 NOISE FIGURE vs. INPUT CARRIER LEVEL
22 21 20 NOISE FIGURE (dB) 19 18 17 16 15 14 13 12 TA = 0C TA = +70C TA = +25C fLO = 2141MHz
MAX2102/05-04insert
16.3 16.1 15.9 NOISE FIGURE (dB) 15.7 15.5 15.3 15.1 14.9 14.7 14.5 800 AGC SET FOR PRFIN = -60dBm 0C NF (dB) +25C NF (dB) +70C NF (dB)
30 fLO = 2151MHz 25 NOISE FIGURE (dB)
23
TA = +70C TA = +25C
20
15 TA = 0C 10 -50 -55 -60 -65 -70 -75 RFIN CARRIER LEVEL (dBm)
1000 1200 1400 1600 1800 2000 2200 LO FREQUENCY (MHz)
-50
-55
-60
-65
RFIN CARRIER LEVEL (dBm)
MAX2102 NOISE FIGURE vs. INPUT CARRIER LEVEL
MAX2102/05-06
MAX2105 NOISE FIGURE vs. INPUT CARRIER LEVEL
MAX2102/05-05insert
INPUT-REFERRED IP3 vs. FREQUENCY
9 8 INPUT IP3 (dBm) 7 6 5 4 3 TA = +70C f1 = fLO - 2MHz f2 = fLO - 2.9MHz PRFIN = -19dBm PER TONE AGC SET VIA SERVO LOOP FOR 0.5Vp-p PER TONE 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 TA = 0C TA = +25C
MAX2102/05-07
30 fLO = 1451MHz 25 NOISE FIGURE (dB) TA = +70C TA = +25C 20
23 22 21 20 NOISE FIGURE (dB) 19 18 17 16 15 14 13 12 TA = 0C TA = +70C TA = +25C fLO = 1441MHz
10
15
TA = 0C
2 1 0
10 -50 -55 -60 -65 -70 -75 RFIN CARRIER LEVEL (dBm)
-50
-55
-60
-65
RFIN CARRIER LEVEL (dBm)
LO FREQUENCY (GHz)
6
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Direct-Conversion Tuner ICs for Digital DBS Applications
Typical Operating Characteristics (continued)
(MAX2102 EV kit circuit (Figure 1), VCC = 5V, PSGND = open, MOD = GND, fRFIN = 2150MHz, PRFIN = -19dBm, fLO = 2150.125MHz, PLO = -15dBm driven single-ended into LO, AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p, IOUT, QOUT drive AC-coupled 100 loads, 2k from PSOUT to GND, TA = +25C, unless otherwise noted.)
LO PORT IMPEDANCE vs. FREQUENCY (UNMATCHED)
MAX2102/05-08
MAX2102/MAX2105
IM3 LEVELS vs. INPUT CARRIER POWER LEVEL
MAX2102/05-09
LO PORT IMPEDANCE vs. FREQUENCY
MATCHED: MAX2102 TYPICAL OPERATING CIRCUIT
MAX2102/05-10
100 50 SERIES IMPEDANCE () REAL 0 -50 -100 -150 -200 0.8 1.1 1.4 1.7 2.0 IMAGINARY
60 50 IM3 LEVEL (dBc) 40 30 20 10 0 TA = 0C TA = +25C TA = +70C f1 = 2148.1MHz f2 = 2149MHz fLO = 2151MHz AGC SET VIA SERVO LOOP FOR 0.5V PER TONE -10 -15 -20 -25 -30 -35
100 80 SERIES IMPEDANCE () 60 40 20 0 -20 -40 0.8 1.1 1.4 1.7 2.0 IMAGINARY
REAL
2.3
-40
2.3
FREQUENCY (GHz)
SINGLE INPUT CARRIER LEVEL (dBm)
FREQUENCY (GHz)
IM3 LEVELS vs. INPUT CARRIERS POWER LEVEL
TA = 0C 60 50 IM3 LEVEL (dBc) TA = +25C 40 TA = +70C 30 20 10 0 -10 -15 -20 -25 -30 -35 -40 SINGLE INPUT CARRIER LEVEL (dBm) f1 = 1448.1MHz f2 = 1449MHz fLO = 1451MHz AGC SET VIA SERVO LOOP FOR 0.5Vp-p PER TONE
MAX2102/05-11
RFIN PORT IMPEDANCE vs. FREQUENCY
MAX2102/05-12
LO LEAKAGE AT RFIN vs. FREQUENCY (SINGLE-ENDED LO DRIVE)
PLO = -5dBm
MAX2102/05-13
70
100 80 60 SERIES IMPEDANCE () 40 20 0 -20 -40 -60 -80 -100 0.8 1.1 1.4 1.7 2.0 MATCHED PER EV KIT CIRCUIT IMAGINARY REAL
-30 -40 LO POWER AT RFIN (dBm) -50 -60 -70 -80 -90 -100 PLO = -15dBm PLO = -10dBm
2.3
0.8
1.1
1.4
1.7
2.0
2.3
FREQUENCY (GHz)
FREQUENCY (GHz)
LO LEAKAGE AT RFIN vs. FREQUENCY (DIFFERENTIAL LO DRIVE)
SPURIOUS SIGNAL LEVEL NORMALIZED TO LEVEL WHEN FRFIN = 1074.5MHz (dBc) AGC SET FOR PRFIN = -69dBm PLO REFERS TO POWER INTO LO AND LO
MAX2102/05-14
SPURIOUS DOWNCONVERSION DUE TO INTERNALLY GENERATED LO 2ND HARMONIC
fLO = 1075.5MHz fRFIN = 2150MHz PRFIN = -69dBm LO DRIVEN SINGLE ENDED
MAX2102/05-15
-30 -40 LO POWER AT RFIN (dBm) -50 -60 -70 -80 -90 -100 0.8 1.1 1.4 1.7 2.0 PLO = -5dBm PLO = -10dBm PLO = -15dBm
-30 -31 -32 -33 -34 -35 -36 LO, LO DRIVEN DIFFERENTIAL (PLO = -15dBm, PLO = -15dBm)
2.3
-20
-15
-10
-5
FREQUENCY (GHz)
LO POWER (dBm)
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7
Direct-Conversion Tuner ICs for Digital DBS Applications MAX2102/MAX2105
Typical Operating Characteristics (continued)
(MAX2102 EV kit circuit (Figure 1), VCC = 5V, PSGND = open, MOD = GND, fRFIN = 2150MHz, PRFIN = -19dBm, fLO = 2150.125MHz, PLO = -15dBm driven single-ended into LO, AGC set via servo loop for VIOUT = VQOUT = 0.5Vp-p, IOUT, QOUT drive AC-coupled 100 loads, 2k from PSOUT to GND, TA = +25C, unless otherwise noted.)
QUADRATURE PHASE IMBALANCE vs. FREQUENCY
MAX2102/05-16
QUADRATURE GAIN IMBALANCE vs. FREQUENCY
QOUT LEVEL RELATIVE TO IOUT LEVEL (dB) 0.4 0.3 0.2 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5 -3 0.85 1.25 1.65 2.05 2.45 0.1 TA = +25C TA = 0C TA = +70C fLO = fRFIN + 125kHz PRFIN = -40dBm PLO = -15dBm
MAX2102/05-17
BASEBAND GAIN FLATNESS vs. FREQUENCY
MAX2102/05-18
QOUT PHASE RELATIVE TO IOUT PHASE (degrees)
93 92 91 90 89 88 87 0.85 1.25 1.65 2.05 TA = +70C TA = +25C fLO = fRFIN + 125kHz PRFIN = -40dBm PLO = -15dBm
0.5
2
TA = 0C
1 BASEBAND GAIN (dB)
TA = +25C TA = +70C
0
-1 TA = 0C -2
2.45
1
10
100
RFIN FREQUENCY (GHz)
RFIN FREQUENCY (GHz)
FREQUENCY (MHz)
BASEBAND GROUP DELAY FLATNESS vs. FREQUENCY
MAX2102/05-19
BASEBAND IM LEVELS
MAX2102/05-20
BASEBAND OUTPUT IMPEDANCE vs. FREQUENCY
BASEBAND OUTPUT IMPEDANCE () 7 6 5 4 3 2 1 0 0.1 1 10 100
MAX2102/05-21
5 4 BASEBAND GROUP DELAY (ns) 3 2 1 0 -1 -2 -3 -4 -5 1 10 FREQUENCY (MHz) TA = 0C TA = +25C TA = +70C
80 70 60 IM LEVELS (dBc) 50 40 30 20 10 0 f1 = 1448.1MHz f2 = 1449MHz fLO = 1451MHz PRFIN = -40dBm PER TONE IM3 IM2
8
100
0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 BASEBAND LEVELS, PER TONE (Vp-p)
FREQUENCY (MHz)
8
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Direct-Conversion Tuner ICs for Digital DBS Applications
Pin Description
PIN 1 2 3, 12 4 5 6 7 8 9, 11, 19, 24 10 13 14 15 16 17 18 20 21 22 23 25 26 27 28 NAME VCC IOUT GND VCC GND VCC RFIN RFIN GND AGC QOUT VCC QDC QDC IDC IDC VCC LO LO VCC PSGND PSOUT MOD VCC FUNCTION Baseband +5V Supply. Bypass with a 10pF capacitor from this pin to pin 3 (GND), as close to the IC as possible. Connect an additional 0.1F capacitor in parallel with the 10pF capacitor (placement less critical). I Channel Baseband Output Baseband Ground RF +5V Supply. Bypass with a 22pF capacitor from this pin to pin 11 (GND), as close to the IC as possible. Ground (substrate) RF +5V Supply. Bypass with a 22pF capacitor from this pin to pin 9 (GND), as close to the IC as possible. RF Noninverting Input. Couple through a 22pF capacitor directly to a 50 signal source. RF Inverting Input. Connect to a 22pF series capacitor and a 51 resistor to ground. RF Ground. Connect directly to the ground plane. Automatic Gain-Control Input. Bypass this pin with a 1000pF capacitor close to the pin, to minimize coupling. Q Channel Baseband Output Baseband +5V Supply. Bypass with a 10pF capacitor from this pin to pin 12 (GND), as close to the IC as possible. Connect an additional 0.1F capacitor in parallel with the 10pF capacitor (placement less critical). Q Channel Offset-Correction Noninverting Input. Connect a 0.22F (typ) capacitor between QDC and QDC. This capacitor must be placed as close to the IC as possible (see Layout Considerations section). Q Channel Offset-Correction Inverting Input. Connect a 0.22F (typ) capacitor between QDC and QDC. This capacitor must be placed as close to the IC as possible (see Layout Considerations section). I Channel Offset-Correction Inverting Input. Connect a 0.22F (typ) capacitor between IDC and IDC. This capacitor must be placed as close to the IC as possible (see Layout Considerations section). I Channel Offset-Correction Noninverting Input. Connect a 0.22F (typ) capacitor between IDC and IDC. This capacitor must be placed as close to the IC as possible (see Layout Considerations section). RF +5V Supply. Bypass with a 10pF capacitor from this pin to pin 19 (GND) as close to the IC as possible. Local-Oscillator Complementary Input Port (Figure 1) Local-Oscillator Input Port (Figure 1) RF +5V Supply. Bypass with a 10pF capacitor from this pin to pin 24 (GND) as close to the IC as possible. Prescaler Ground. To disable the prescaler, leave this pin open. Prescaler Output. Drives CMOS load. Connect 2k from this pin to GND (if the prescaler is enabled). Prescaler Modulus Control. Leave open when the prescaler is disabled. Prescaler +5V Supply. Must be connected even if the prescaler is disabled. Bypass with a 1000pF capacitor.
MAX2102/MAX2105
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9
Direct-Conversion Tuner ICs for Digital DBS Applications MAX2102/MAX2105
VCC 47F 0.1F 100 LOAD 10pF 1 2 3 4 5 22pF VCC RF INPUT (50 SOURCE) 22pF 51 22pF 22pF 6 7 8 9 VCC IOUT MOD 0.1F VCC GND VCC GND PSOUT PSGND GND VCC 28 1000pF 27 26 25 2k 24 10pF VCC RFIN RFIN GND MODULUS CONTROL PRESCALER OUTPUT VCC
MAX2102 MAX2105
VCC LO LO VCC
23 22pF 22 22pF 21 20 10pF 56 22
VCC LO INPUT (50 SOURCE)
33
AGC CONTROL 1000pF
10 11 12 13
AGC GND
GND IDC
19 18 0.22F 17 16 0.22F
VCC
47F
GND QOUT VCC
IDC QDC QDC
100 LOAD
0.1F 0.1F VCC
10pF 14 15
Figure 1. Typical Operating Circuit
Detailed Description
The MAX2102/MAX2105 down-convert signals in the range 950MHz to 2150MHz directly to baseband I/Q signals. They are targeted for digital DBS tuner applications where a direct downconversion provides a cost savings over prior-art, multiple-conversion approaches. However, the MAX2102/MAX2105 are applicable to any system requiring a broadband I/Q downconversion. Internally, the MAX2102 and MAX2105 consist of a broadband front-end variable gain stage, a quadrature downconverter, an oscillator buffer, high-linearity I and Q baseband amplifiers, and offset correction amplifiers. The MAX2102 features a front-end AGC dynamic range of over 50dB, while the MAX2105 provides a front-end
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AGC dynamic range of over 41dB. Specifically, the AGC control can be adjusted so that a sine wave at RFIN ranging in power from -69dBm to -19dBm (MAX2102) or -60dBm to -19dBm (MAX2105) will produce a sine wave at IOUT and QOUT at 500mVp-p levels. The noise figure is lowest when the AGC is at its maximum gain setting (see Typical Operating Characteristics). The VSWR at RFIN is unaffected by the AGC setting. The local-oscillator (LO) buffer accepts an external LO signal at LO, LO, and internally limits the signal to provide a consistent on-chip LO level. The LO input drive level should be maintained within the specified limits (see Applications Information section).
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Direct-Conversion Tuner ICs for Digital DBS Applications MAX2102/MAX2105
The quadrature downconverter follows the front-end AGC. Two mixers are driven by the previous stage AGC amplifier output. The mixer LO ports are fed with the two LO signals, which are 90 apart in phase. These quadrature LO signals are generated on-chip using the LO signal from the LO buffer. The resulting I/Q baseband signals are fed through separate I and Q channel baseband amplifiers. Robust output stages drive IOUT and QOUT. The outputs are capable of driving lowpass filters with 100 characteristic impedance (that is, the equivalent of an AC-coupled, 100 load). The baseband -3dB output bandwidth is over 90MHz.
__________Applications Information
Front-End Tuner Circuitry for DBS Tuners
In a typical application, the signal path ahead of the MAX2102/MAX2105 will include a discrete LNA/buffer and a PIN-diode attenuator. Alternatively, a dual-gate
LNB 75 CABLE 950MHz to 2150MHz F-CONNECTOR FOR 2nd SET-TOP BOX F-CONNECTOR INPUT
KU BAND
OR
AGC RFIN
IOUT 0.1F R S C1
L1 C2
L2 C3
L3 C4
0.1F ADC
AGC
RFIN 0 90 EXTERNAL VCO LO 0.1F RS DIV LO TANK OR TSA5055 OR EQUIV. IDC IDC QDC QDC PSOUT MOD OFFSET CORRECTION C1 C2 C3 C4
MAX2102 MAX2105
QOUT BASEBAND LP FILTERS L1 L2 L3
RL
MAX1002 MAX1003
(OPTIONAL GAIN)
DSP: QPSK DEMOD
0.1F ADC
RL
Figure 2. Typical Application
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Direct-Conversion Tuner ICs for Digital DBS Applications
GaAsFET can serve this function. This circuitry is usually required in order to meet system noise-figure requirements, may provide a buffered F-connector output, and may also be required to meet stringent LO leakage requirements. The PIN attenuator is typically controlled by the same voltage as the MAX2102/MAX2105 AGC control pin so that, overall, a single AGC line from the baseband processor can control the entire tuner. In some applications, a varactor-tuned preselection bandpass filter is added between the discrete LNA and the MAX2102/MAX2105. This is usually required only for very high-linearity tuners, such as those designed for single channel-per-carrier (low-data-rate) applications. The filter provides a means of broadly filtering adjacent interferers, thus improving the tuner's intermodulation performance. Additionally, the filter removes the RF interference at twice the LO frequency, which would otherwise add to cochannel interference (the MAX2102/MAX2105 alone reject this carrier to typically -32.3dBc).
MAX2102/MAX2105
22
22pF
LO 22
56
MAX2102 MAX2105
22 22pF LO 21 56
LO POWER: -15dBm TO -5dBm, POWER INTO LO, LO. LO, LO DRIVEN DIFFERENTIALLY
External Oscillator
Since the MAX2102/MAX2105 are direct-conversion receivers, the external LO must tune to the same frequencies as the desired RF input signals. The MAX2102/MAX2105 oscillator input port (LO, LO) accepts either a single-ended or differential (balanced) LO signal. A differential LO offers reduced LO leakage to the RFIN port, as well as lower spurious downconversion levels of RF signals, which are at twice the LO frequency. Refer to Figure 3 for differential LO connections. For best performance, ensure that the LO and LO traces are symmetrical. The LO drive levels should be maintained to within the specified limits. If the LO drive falls below the specified range, quadrature performance may be affected. Driving LO above the specified limits will cause a higher LO leakage level at RFIN; this may be acceptable in some applications. The MAX2102/MAX2105 offset-correction loop can withstand LO leakage levels corresponding to at least 0dBm of LO input power drive.
Figure 3. Differential LO Drive
To use the MAX2102/MAX2105 prescaler, connect the PSGND pin to ground. In some applications, the prescaler may be toggled on and off using a MOSFET to switch PSGND to ground. PSGND should be forced to within 100mV of ground, and the MOSFET must be capable of sinking 15mA. PSOUT is capable of driving a typical CMOS load of 10k in parallel with 5pF. A 2k pull-down resistor must be connected from PSOUT to GND. The prescaler requires a stable level at the MOD pin 12ns before the falling edge of PREOUT to assert the desired modulus. The level at MOD must remain static until 3ns after this falling edge.
Baseband Amplifiers
The MAX2102/MAX2105 baseband amplifiers provide over 2Vp-p swing at IOUT and QOUT, and are capable of driving 100. IOUT and QOUT must be AC-coupled to any lowpass filters. In a typical application, IOUT and QOUT drive a 5th or 7th-order lowpass filter for ADC anti-aliasing purposes (see the Systems Considerations: Lowpass Filters in Direct-Conversion Tuners section). After the filters, in some cases, additional gain may be required. This can be accomplished with a pair of videospeed op amps, such as the MAX4216 dual-video op amp. Alternatively, the MAX1002/MAX1003 dual ADC has built-in gain ahead of the ADCs, digitizing levels as low as 125mVp-p. Contact Maxim for more information about the MAX4216 or the MAX1002/MAX1003.
Prescaler
Typical stand-alone tuner applications will not use the MAX2102/MAX2105 prescaler function, but instead use a commercial synthesizer IC such as the Philips TSA5055, which has an internal prescaler. To disable the MAX2102/MAX2105 prescaler, disconnect the PSGND pin (leave open). The prescaler will cause an output spur in the baseband spectrum, to a level of about -20dBc (referred to 500mVp-p baseband output level) that may land within the desired signal bandwidth in some applications.
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Direct-Conversion Tuner ICs for Digital DBS Applications
Offset Correction
The internal offset-correction amplifiers remove the DC offsets present in the baseband amplifiers. The offsetcorrection loop effectively AC-couples the baseband signal path, yielding a -3dB highpass corner frequency according to the following: f-3dB = 100/CDC (F) where C DC is the value of the capacitors, in microfarads, across QDC, QDC and IDC, IDC. For applications where the DC information must be maintained through the signal path, the offset correction can be disabled by connecting QDC, QDC, IDC, and IDC directly to ground. Disabling the offset correction will effectively limit the input dynamic range of the MAX2102/MAX2105. Typical input dynamic range will be approximately -45dBm to -19dBm for single-ended LO drive, and -55dBm to -19dBm for differential LO drive. plane under the external VCO area to reduce parasitic capacitance. If a ground plane is used under the lowpass filters, note that the filter shape may be slightly offset due to parasitic capacitance. In a direct-conversion receiver, LO leakage to the RF input connector is a major issue, since filtering of the LO is impossible (the LO operates at the same frequency as the RF input). The external VCO section should be housed in a separate shielded compartment, if possible. Use of a differential (balanced) LO will dramatically reduce LO leakage. Also, the use of coplanar, waveguide transmission-line structures reduces LO leakage (used on the MAX2102 EV kit). Observe the power-supply bypass capacitor connections in the Pin Description table, notably pins 1, 3, 4, 6, 9, 11, 12, 14, 19, 20, 23, and 24. Traces from these IC pins to the bypass capacitors must be kept to an absolute minimum. Where possible, make these connections on the top side of the board. The MAX2102 EV kit includes ferrite beads in series with power-supply leads. The beads may not be required for all applications.
MAX2102/MAX2105
Layout Considerations
Observe standard RF layout rules. A ground plane is essential; when connecting areas of ground plane between layers, use vias liberally. Remove the ground
Table 1. Suggested Component Values for Discrete Lowpass Filters (0.1dB Ripple Chebyshev Type)
ADC SAMPLING RATE (Msps) 40 60 90 FILTER TYPE 0.1dB Chebyshev, fC = 20MHz 0.1dB Chebyshev, fC = 30MHz 0.1dB Chebyshev, fC = 45MHz RS () 100 100 100 C1 (pF) 39 22 18 L1 (nH) 910 620 390 C2 (pF) 120 82 56 L2 (nH) 1500 910 620 C3 (pF) 150 100 68 L3 (nH) 1500 1000 680 C4 (pF) 120 82 56 RL (k) 10 10 10
Note: Suggested types: Inductors: Coilcraft 1008CS, tolerance = 5%; Capacitors: use tolerance = 2%. Refer to Figure 2 for circuit diagram.
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13
Direct-Conversion Tuner ICs for Digital DBS Applications MAX2102/MAX2105
Power-Supply Sequencing
The MAX2102/MAX2105 have several +5V supply pins. The supply layout should be in a star format, with a bypass capacitor that dominates the rise time of the supply at the center of the star, to ensure that all pins see approximately the same voltage during power-up. The prescaler VCC (pin 28) must be connected to the same VCC as the other VCC pins, even if the prescaler is not used. Leaving PSGND open will disable the prescaler function and, in this state, the prescaler will not dissipate any power.
Systems Consideration: Lowpass Filters in Direct-Conversion Tuners
Typically, a 5th or 7th-order L-C lowpass filter is used for anti-aliasing the ADCs following the MAX2102. Figures 4 and 5 describe typical filtering requirements. Table 1 offers suggested component values for these lowpass filters.
Chip Information
TRANSISTOR COUNT: 1852 SUBSTRATE CONNECTED TO GND
I
MAX2102 MAX2105
Q
ANALOG LP FILTERS
ADCs
MATCHED FILTERS
DIGITAL SIGNAL PROCESSING "1" "2" "3" "4"
Figure 4. I, Q Signal Path
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Direct-Conversion Tuner ICs for Digital DBS Applications MAX2102/MAX2105
TRANSPONDER BW = 24MHz 0
AT SIGNAL POINT NO. 1
dBc -30 0
DESIRED CHANNEL (20Msps) 10 12 DATA NYQUIST 17.16 = 0.2 NYQUIST FOR ADC 20
UNDESIRED ADJACENT CHANNEL
29.16
40 41.16
MHz
ADC SAMPLING
TRANSPONDER SPACING = 29.16 MHz
LOWPASS FILTER RESPONSE 0
AT SIGNAL POINT NO. 2
dBc -30 0
DESIRED CHANNEL (20Msps) 10 12 17.16 20 28 FILTER CUTOFF ADC SAMPLING 40 MHz
PASSBAND FILTER REQUIREMENTS: (1) <20% OF BAUD PERIOD DELAY RIPPLE (2) <0.1dB GAIN RIPPLE TRANSITION BAND FILTER REQUIREMENTS: < 2dB GAIN RIPPLE
0
AT SIGNAL POINT NO.3
dBc -30 0
DESIRED CHANNEL (20Msps) 10 12
ADJ CHANNEL FOLDOVER 17.16 20 40 MHz
ADC NYQUIST
ADC SAMPLING
DIGITAL MATCHED FILTER
AT SIGNAL POINT NO.4
dBc -30 0
DESIRED CHANNEL (20Msps) 10 12 40 MHz
ADC SAMPLING
Figure 5. Lowpass Filtering Example. Note: Data Rate = 40Mbps, Transponder BW = 24MHz, Transponder Spacing = 29.16MHz, Nyquist Filter: = 0.2
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Direct-Conversion Tuner ICs for Digital DBS Applications MAX2102/MAX2105
________________________________________________________Package Information
SOICW.EPS
16
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