Rainbow Electronics MAX2108 User Manual

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone].

General Description

The MAX2108 is a low-cost direct-conversion tuner IC
designed for use in digital direct-broadcast satellite
(DBS) television set-top box units and microwave links.
Its direct-conversion architecture reduces system cost
compared to devices with IF-based architectures.

The MAX2108 directly tunes L-band signals to base­band using a broadband I/Q downconverter. The oper­ating frequency range spans from 950MHz to
2150MHz. The IC includes a low-noise amplifier (LNA)
with gain control, two downconverter mixers with output
buffers, a 90° quadrature generator, and a divide-by
32/33 prescaler.

Applications

DirecTV, PrimeStar, EchoStar DBS Tuners
DVB-Compliant DBS Tuners
Cellular Base Stations
Wireless Local Loop
Broadband Systems
LMDS
Microwave Links

Features

♦ Low-Cost Architecture
♦ Operates from Single +5V Supply
♦ On-Chip Quadrature Generator, Dual-Modulus

Prescaler (/32, /33)

♦ Input Levels: -20dBm to -70dBm per Carrier
♦ Over 50dB RF Gain-Control Range
♦ 10dB Noise Figure at Maximum Gain
♦ +8dBm IIP3 at Minimum Gain

MAX2108

Direct-Conversion Tuner IC

________________________________________________________________

Maxim Integrated Products

1

PS_SEL GC GND GND RFIN

RFIN

GND IOUT

IOUT

PSOUT

V

CC

V

CC

V

CC

V

CC

PSOUT GND GND N.C. LO LO QOUT QOUT

N.C. GND

1211109 876543 21

13 14 15 16 17 18 19 20 21 22 23 24

MAX2108

/32
/33

90

Q

0

I

Functional Diagram

19-1449; Rev 0; 4/99

PART

MAX2108CEG 0°C to +70°C

TEMP. RANGE PIN-PACKAGE

24 QSOP

Ordering Information

Pin Configuration appears at end of data sheet.

MAX2108

Direct-Conversion Tuner IC

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(VCC= +4.75V to +5.25V; VGC= 1.3V; PS_SEL = 0.5V; IOUT, IOUT, QOUT, QOUT = terminated with 2.5kΩ to GND; no input signal

applied; T

A

= 0°C to +70°C; unless otherwise noted. Typical values are at VCC= +5V, TA= +25°C.)

AC ELECTRICAL CHARACTERISTICS

(VCC= +5V; PS_SEL = 0.5V; P

RFIN

= -20dBm; fLO= f

RFIN

+125kHz; GC set via servo loop for V

IOUT

- V

IOUT

= 200mVp-p (differen-

tial); T

A

= +25°C; 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.

VCCto GND..............................................................-0.3V to +7V

V

CC

to Any Other VCC...........................................-0.3V to +0.3V

All Other Pins to GND.................................-0.3V to (V

CC

+ 0.3V)

RFIN to RFIN ..........................................................................±2V

LO to LO ................................................................................±2V

Short-Circuit Current

IOUT, IOUT, QOUT, QOUT to GND.................................10mA

PSOUT, PSOUT to GND...................................................40mA

Short-Circuit Duration IOUT to IOUT, QOUT to QOUT,

PSOUT to PSOUT ............................................................10sec

Continuous Power Dissipation (T

A

= +70°C)

24 QSOP (derate 10mW/°C above T

A

= +70°C) ..........800mW

Operating Temperature Range...............................0°C to +70°C

Junction Temperature......................................................+150°C

Storage Temperature Range.............................-65°C to +150°C

Lead Temperature (soldering, 10sec).............................+300°C

0 < V

PS_SEL

< V

CC

1V < VGC< 4V

CONDITIONS

V0.5V

THL

PS_SEL Logic-Low Threshold

V2.4V

THH

mA105 152I

CC

Supply Current
PS_SEL Logic-High Threshold

µA-30 +10I

PS_SEL

PS_SEL Input Bias Current

µA-80 +80I

GC

GC Input Bias Current

UNITSMIN TYP MAXSYMBOLPARAMETER

V2.9 3.35 3.8V

CM

IOUT, IOUT, QOUT, QOUT
Common-Mode Output Voltage

950MHz < f

RFIN

< 2150MHz, PLO= -5dBm,

V

IOUT

- V

IOUT

= 10mVp-p, TA= 0°C +70°C

950MHz < f

RFIN

< 2150MHz, PLO= -5dBm

1V < VGC< 4V, PLO= -5dBm

CONDITIONS

dBm-70P

RFINMIN

RFIN Minimum Input Power
(Note 2)

dBm-20P

RFINMAX

MHz950 2150f

RFIN

RFIN Frequency Range (Note 1)
RFIN Maximum Input Power

(Note 2)

dBm

-5

External LO Drive Level (Note 2)

dB50Gain-Control Range (Note 2)

UNITSMIN TYP MAXSYMBOLPARAMETER

VGC= 4V, fLO= 1750MHz dB10NFNoise Figure

dBm14IIP

2

dBm8IIP

3

RFIN Input Third-Order
Intercept Point (Note 3)

RFIN Input Second-Order
Intercept Point (Note 4)

MAX2108

Direct-Conversion Tuner IC

_______________________________________________________________________________________ 3

AC ELECTRICAL CHARACTERISTICS (continued)

(VCC= +5V; PS_SEL = 0.5V; P

RFIN

= -20dBm; fLO= f

RFIN

+125kHz; GC set via servo loop for V

IOUT

- V

IOUT

= 200mVp-p (differen-

tial); T

A

= +25°C; unless otherwise noted.)

Note 1: AC specifications with minimum/maximum limits are met within this frequency range.
Note 2: LO and LO are differentially driven through an AC-coupled matching network.
Note 3: P

RFIN

= -20dBm per tone, GC set via servo loop for V

IOUT

- V

IOUT

= 20mVp-p per tone. f1

RFIN

= 1749MHz, f2

RFIN

=

1751MHz, f

LO

= 1740MHz.

Note 4: P

RFIN

= -20dBm per tone, GC set via servo loop for V

IOUT

- V

IOUT

= 20mVp-p per tone. f1

RFIN

= 1200MHz, f2

RFIN

=

2150MHz, f

LO

= 951MHz.

CONDITIONS UNITSMIN TYP MAXSYMBOLPARAMETER

V

PS_SEL

< 0.5V

C

PSOUT

= C

PSOUT

= 10pF to GND

33 33

V

PS_SEL

> 2.4V

Prescaler Divide Ratio

Vp-p1.0

V

PSOUT -

V

PSOUT

Differential Prescaler Output
Swing

32 32

At -3dB attenuation
f

IOUT

= f

IOUT

= f

QOUT

= f

QOUT

= 20MHz

MHz150

f

IOUT

= f

IOUT

= f

QOUT

= f

QOUT

= 125kHz

Baseband Bandwidth

Ω33

I/Q Channel Differential
Output Impedance

degrees3

I/Q Channel Quadrature
Phase Error (Note 2)

f

IOUT

= f

IOUT

= f

QOUT=fQOUT

= 125kHz dB1

I/Q Amplitude Mismatch
(Note 2)

f

IOUT

= f

IOUT

= f

QOUT

= f

QOUT

= 10MHz,

no output load

Vp-p1.4I/Q Channel Clipping Level

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

90

100

95

110

105

120

115

125

4.75 4.954.85 5.05 5.15 5.25

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX2108 toc01

VCC(V)

I

CC

(mA)

TA = +70°C

TA = +25°C

TA = 0°C

-80

-70

-60

-50

-40

-30

-20

-10

0

1 1.5 2 2.5 3 3.5

CARRIER LEVEL vs. GAIN CONTROL

MAX2108 toc02

GC VOLTAGE (V)

RF LEVEL (dBm)

GC SET FOR 10mVp-p
BASEBAND OUTPUT

f

RFIN

= 1750 MHz

0

2

4

6

8

10

900 13001100 1500 1700

INPUT IP3 vs. FREQUENCY

MAX2108 toc03

RF FREQUENCY (MHz)

IIP3 (dBm)

TWO-TONE FREQUENCY
SPACING EQUALS 2MHz

MAX2108

Direct-Conversion Tuner IC

4 _______________________________________________________________________________________

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

0

20
10

30

60

70

50
40

80

-55 -45 -40 -35 -30-50 -25 -20 -15 -10

IM3 vs. CARRIER LEVEL

MAX2108 toc04

RF INPUT LEVEL (dBm)

IM3 (dBc)

TWO-TONE FREQUENCY
SPACING EQUALS 2MHz

5

7
6

9
8

11
10

12

14
13

15

950 1150 1350 1550 1750

NOISE FIGURE vs. FREQUENCY

MAX2108 toc05

RF FREQUENCY (MHz)

NF (dB)

VGC = 4V

5

10

15

20

25

20 26 2822 24 30 32 34 36 38

NOISE FIGURE vs. INSERTION GAIN

(RF TO BASEBAND)

MAX2108 toc06

GAIN (dB)

NF (dB)

-40

-20

-30

20
10

0

-10

40
30

900 1100 1300 1500 1700 1900 2100

RF PORT SERIES IMPEDANCE

vs. FREQUENCY

MAX2108 toc07

FREQUENCY (MHz)

SERIES IMPEDANCE (Ω)

VGC = 4V

REAL

IMAGINARY

-70

-40

-50

-60

-20

-30

20
10

0

-10

40
30

900 1100 1300 1500 1700 1900 2100

RF PORT SERIES IMPEDANCE

vs. FREQUENCY

MAX2108 toc08

FREQUENCY (MHz)

SERIES IMPEDANCE (Ω)

REAL

IMAGINARY

VGC = 1V

-70

-40

-50

-60

-20

-30

20
10

0

-10

30

900 1100 1300 1500 1700 1900 2100

LO PORT SERIES IMPEDANCE

vs. FREQUENCY

MAX2108 toc10

FREQUENCY (MHz)

SERIES IMPEDANCE (Ω)

REAL

IMAGINARY

SINGLE-ENDED

0.1 101 100 1000

NORMALIZED BASEBAND GAIN

vs. BASEBAND FREQUENCY

MAX2108 toc11

BASEBAND FREQUENCY (MHz)

NORMALIZED BASEBAND GAIN (dB)

5

-5

0