19-3025; Rev 0; 11/03
IT
TION K
VALUA
E
BLE
AVAILA
Quad-Output LNA with AGC for
Cable TV Applications
General Description
Features
♦
Quad Outputs with Independent AGCs and
Shutdown
♦
50MHz to 878MHz Broadband Operation
♦
Integrated Power Detector
♦
High Linearity: 15.6dBm IIP3
MAX3558
The MAX3558 broadband quad-output low-noise ampli-
fier (LNA) is designed for digital set tops and digital ter-
restrial applications. The LNA covers a 50MHz to
878MHz input frequency range, while integrating a sep-
arate automatic gain-control (AGC) function with over
30dB of control range for each of four balanced out-
puts. Each output has its own shutdown control to
reduce power consumption when not used. The
MAX3558 also includes a power detector that can be
used to close the loop on any of the AGCs to prevent
overload conditions. The LNA’s attack point is
adjustable with an external resistor. The MAX3558 is
available in a very small 28-pin QFN package with
exposed paddle (EP).
Applications
Digital Set-Top Boxes
Digital Terrestrial Receivers
Tuner Preamps
PART
MAX3558CGI
Ordering Information
TEMP RANGE
0°C to +70°C
PIN-PACKAGE
28 QFN-EP*
(5mm x 5mm)
*EP
= Exposed paddle.
Pin Configuration/Functional Diagram
TOP VIEW
SHDN1
AGC1
OUT1+
OUT1-
28
27
26
25
24
V
CC
23
22
SHDN2
V
CC
BIAS
LB
RFIN+
RFIN-
V
CC
PDAGC
PDOUT
1
21 OUT2+
MAX3558
2
3
4
5
6
7
POWER
DETECTOR
20 OUT2-
19 AGC2
18 GND
17 AGC3
16 OUT3-
15 OUT3+
8
9
10
11
12
13
14
OUT4+
SHDN4
EXPOSED PADDLE IS CONNECTED TO GND
________________________________________________________________
Maxim Integrated Products
SHDN3
PDREF
OUT4-
AGC4
V
CC
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Quad-Output LNA with AGC for
Cable TV Applications
MAX3558
ABSOLUTE MAXIMUM RATINGS
V
CC
, OUT_ _ to GND ............................................-0.3V to + 6.3V
BIAS, LB, RFIN_, PDAGC, PDOUT, PDREF,
SHDN_,
AGC_ to GND ...........................-0.3V to (V
CC
+ 0.3V)
OUT_ _ Short-Circuit Duration....................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
28-Pin QFN.......................................................................2.1W
CAUTION!
ESD SENSITIVE DEVICE
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.
Operating Temperature Range...............................0°C to +70°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering ,10s) .................................+300°C
DC ELECTRICAL CHARACTERISTICS
(V
CC
= 4.75V to 5.25V, no RF signal applied, R
BIAS
= 1.1kΩ,
R
PDREF
= 10kΩ, L
LB
= 82nH, T
A
= 0°C to +70°C, unless otherwise
noted. Typical values are at V
CC
= 5V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
Supply Voltage
CONDITIONS
Four outputs active, V
AGC_
= 3V
Three outputs active, V
AGC_
= 3V
Supply Current
Four outputs active, 10dB gain reduction
Four outputs active, V
AGC_
= 0.5V
Four outputs shut down
Power-Detector Output Current
Analog Input Current
Logic-Low Input Voltage
Logic-High Input Voltage
Logic Input Current
2.0
-100
+10
PDOUT = V
CC
- 0.5V
PDOUT = 0.5V
AGC_, PDAGC = 0 to 5V
1
-0.8
-100
+100
0.8
MIN
4.75
TYP
241
206
306
329
103
MAX
5.25
287
245
366
396
121
mA
µA
V
V
µA
mA
UNITS
V
2
_______________________________________________________________________________________
Quad-Output LNA with AGC for
Cable TV Applications
AC ELECTRICAL CHARACTERISTICS
(V
CC
= 4.75V to 5.25V, f
RFIN
= 50MHz to 878MHz, 75Ω system impedance, V
AGC_
= 3V, V
SHDN_
= V
CC
, R
BIAS
= 1.1kΩ, R
PDREF
= 10kΩ,
L
LB
= 82nH, T
A
= 0°C to +70°C, unless otherwise noted. Typical values are at V
CC
= 5V, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Frequency Range
Voltage Gain
Gain Flatness
Noise Figure
Input P1dB Compression Point
Input 3rd-Order Intercept Point
(IIP3) (Note 3)
Input 2nd-Order Intercept Point
(IIP2) (Note 3)
Input Return Loss
Output Return Loss
OUT_ to RFIN Isolation
RFIN to OUT_ Shutdown Isolation
Output-to-Output Isolation
Power-Detector Operating Range
(per Channel)
AGC Attack Range (per Channel)
AGC Attack Accuracy
(per Channel)
Attack Point Variation
AGC Attack Slope
VGA in shutdown, f
RFIN
= 54MHz to 72MHz
Between any two outputs
f
RFIN
= 50MHz to 878MHz (Note 4)
R
PDREF
= 800Ω to 12kΩ, flat input of 130 channel
loading (Notes 4, 5)
130 channel loading (Notes 2, 4)
Any one output in shutdown mode (Note 4)
Change of POUT_ over 12dB change in P
RFIN
after
reaching AGC attack point (Notes 2, 4)
CONDITIONS
Gain specification is met across the frequency band
Differential output load, maximum gain (Note 2)
Differential output load, V
AGC_
= 0.5V, minimum gain
50MHz to 878MHz
Worst case across band, 75Ω source, at maximum gain
Maximum gain
10dB gain reduction
Maximum gain, P
IN
= -9dBm
10dB gain reduction, P
IN
= -9dBm (Note 2)
Maximum gain, P
IN
= -9dBm
10dB gain reduction, P
IN
= -9dBm (Note 2)
Any gain setting
75Ω differential output load
8
65
40
45
-3
-3
-2.2
-0.5
-2
+17
+6
+2.2
+0.5
+2
+29.5
9
-1.1
+1.3
14.4
15.6
+45.9
MIN
50
4.0
6.8
-27.6
±0.4
8.4
9.9
TYP
MAX
878
9.3
-15.7
UNITS
MHz
dB
dB
dB
dBm
dBm
dBm
dB
dB
dB
dB
dB
dBmV
dBmV
dBmV
dBm
dB
MAX3558
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Guaranteed by design and characterization.
Guaranteed by production test.
Measured with two input tones (f
1
= 800MHz, f
2
= 845MHz).
PDOUT connected to PDAGC and AGC_.
P
IN
is single-tone equivalent to 130 channel loading.
_______________________________________________________________________________________
3
Quad-Output LNA with AGC for
Cable TV Applications
MAX3558
Typical Operating Characteristics
(MAX3558 EV kit, V
CC
= 5V, f
RFIN
= 50MHz to 878MHz, V
AGC_
= 3V, V
SHDN_
= V
CC
, R
BIAS
= 1.1kΩ, R
PDREF
= 10kΩ, L
LB
= 82nH, T
A
=
+25°C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX3558 toc01
GAIN vs. FREQUENCY
9
8
7
GAIN (dB)
GAIN (dB)
6
5
4
3
2
1
0
T
A
= 0°C
T
A
= +25°C
T
A
= +70°C
V
CC_
= 5V
V
AGC_
= 3V
MAX3558 toc02
GAIN vs. FREQUENCY
9
8
7
6
5
4
3
2
1
0
V
CC
= 4.75V, 5V, 5.25V
V
AGC_
= 3V
T
A
= +25°C
MAX3558 toc03
280
V
AGC_
= 3V
270
SUPPLY CURRENT (mA)
260
250
240
230
220
210
200
4.5
4.7
4.9
5.1
5.3
T
A
= +70°C
T
A
= +25°C
T
A
= 0°C
10
10
5.5
50 150 250 350 450 550 650 750 850
FREQUENCY (MHz)
50 150 250 350 450 550 650 750 850
FREQUENCY (MHz)
SUPPLY VOLTAGE (V)
GAIN vs. FREQUENCY
12
10
8
6
4
2
0
-2
-4
-6
-8
-10
-12
GAIN (dB)
MAX3558 toc04
NOISE FIGURE vs. FREQUENCY
MAX3558 toc05
NOISE FIGURE vs. GAIN
35
30
NOISE FIGURE (dB)
T
A
= +25°C
50MHz
MAX3558 toc06
V
AGC_
= 3V
V
AGC_
= 1.97V
V
AGC_
= 1.81V
V
AGC_
= 1.69V
V
AGC_
= 1.59V
V
AGC_
= 1.50V
V
AGC_
= 1.42V
V
AGC_
= 1.35V
V
AGC_
= 1.28V
V
CC_
= 5V
T
A
= +25°C
12
V
AGC_
= 3V
10
NOISE FIGURE (dB)
8
6
4
2
0
T
A
= +25°C
T
A
= 0°C
T
A
= +70°C
40
25
20
15
10
5
0
390MHz
857MHz
50 150 250 350 450 550 650 750 850
FREQUENCY (MHz)
50 150 250 350 450 550 650 750 850
FREQUENCY (MHz)
-25
-20
-15
-10
-5
0
5
10
GAIN (dB)
IIP3 vs. FREQUENCY
MAX3558 toc07
IIP3 vs. FREQUENCY
MAX3558 toc08
IIP2 vs. FREQUENCY
V
AGC_
= 3V
MAX3558 toc09
22
20
18
16
IIP3 (dBm)
14
12
10
8
6
4
2
0
T
A
= +25°C
T
A
= +70°C
T
A
= 0°C
V
AGC_
= 3V
22
20
18
16
IIP3 (dBm)
12
10
8
6
4
2
0
T
A
= 0°C
14
T
A
= +70°C
10dB GAIN
REDUCTION
60
50
40
IIP2 (dBm)
30
20
10
f
A
+ f
B
= 860MHz
0
T
A
= +25°C
T
A
= 0°C
T
A
= +70°C
T
A
= +25°C
50 150 250 350 450 550 650 750 850 950
FREQUENCY (MHz)
50 150 250 350 450 550 650 750 850 950
FREQUENCY (MHz)
50
150
250 350 450 550 650 750 850
FREQUENCY f
A
(MHz)
4
_______________________________________________________________________________________
Quad-Output LNA with AGC for
Cable TV Applications
MAX3558
Typical Operating Characteristics (continued)
(MAX3558 EV kit, V
CC
= 5V, f
RFIN
= 50MHz to 878MHz, V
AGC_
= 3V, V
SHDN_
= V
CC
, R
BIAS
= 1.1kΩ, R
PDREF
= 10kΩ, L
LB
= 82nH, T
A
=
+25°C, unless otherwise noted.)
IIP2 vs. FREQUENCY
MAX3558 toc10
IIP2 vs. FREQUENCY
MAX3558 toc11
IIP2 vs. FREQUENCY
T
A
= +70°C
50
40
V
AGC_
= 1.5V
MAX3558 toc12
60
50
40
IIP2 (dBm)
T
A
= +25°C
T
A
= +70°C
60
T
A
= +70°C
50
40
IIP2 (dBm)
T
A
= +25°C
30
20
T
A
= 0°C
V
AGC_
= 3V
60
IIP2 (dBm)
30
20
10
0
50
150
T
A
= 0°C
30
20
T
A
= +25°C
T
A
= 0°C
f
A
- f
B
= 50MHz
10dB GAIN REDUCTION
10dB GAIN REDUCTION
f
A
+ f
B
= 860MHz
250 350 450 550 650 750 850
FREQUENCY f
A
(MHz)
10
0
f
A
- f
B
= 50MHz
10
0
50 150 250 350 450 550 650 750 850 950
FREQUENCY f
A
(MHz)
50 150 250 350 450 550 650 750 850 950
FREQUENCY (MHz)
AGC ATTACK POINT vs. R
PDREF
8
AGC ATTACK POIN T (dBmV)
6
4
2
0
-2
-4
-6
-8
-10
0
1
2
3
4
5
6
7
8
9 10 11 12
R
PDREF
(kΩ)
SINGLE-TONE INPUT
EQUIVALENT TO 130
CHANNEL LOADING
V
CC_
= 5V
T
A
= +25°C
MAX3558 toc13
PORT-TO-PORT ISOLATION
vs. FREQUENCY
MAX3558 toc14
OUTPUT TO RFIN ISOLATION
vs. FREQUENCY
-10
-20
ISOLATION (dB)
-30
-40
-50
-60
-70
-80
-90
-100
V
AGC_
= 3V
T
A
= +25°C
MAX3558 toc15
10
0
-10
-20
ISOLATION (dB)
-30
-40
-50
-60
-70
-80
-90
-100
50 150 250 350 450 550 650 750 850
FREQUENCY (MHz)
V
AGC_
= 3V
T
A
= +25°C
0
50 150 250 350 450 550 650 750 850
FREQUENCY (MHz)
RFIN TO OUTPUT ISOLATION
vs. FREQUENCY
MAX3558 toc16
INPUT RETURN LOSS vs. FREQUENCY
MAX3558 toc17
OUTPUT RETURN LOSS vs. FREQUENCY
-2
OUTPUT RETURN LOSS (dB)
-4
-6
-8
-10
-12
-14
-16
-18
-20
MAX GAIN AND MIN GAIN
75Ω SYSTEM
MAX3558 toc18
0
-10
-20
ISOLATION (dB)
-30
-40
-50
-60
-70
-80
-90
-100
50 150 250 350 450 550 650 750 850
FREQUENCY (MHz)
V
AGC_
= 3V
T
A
= +25°C
VGA IN SHUTDOWN
0
-2
INPUT RETURN LOSS (dB)
-4
-6
-8
-10
-12
-14
-16
-18
-20
0
200
400
600
800
MAX GAIN AND MIN GAIN
75Ω SYSTEM
0
1000
0
200
400
600
800
1000
FREQUENCY (MHz)
FREQUENCY (MHz)
_______________________________________________________________________________________
5
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