19-2339; Rev 1; 3/02
KIT
ATION
EVALU
E
BL
AVAILA
Upstream CATV Amplifier
General Description
Features
o
Single 3.3V Supply Operation
o
Accurate Gain Control, ±1dB over 53dB Range
o
Gain Programmable in 0.5dB Steps
o
-55dBc Harmonic Distortion at 65MHz
o
Low Burst On/Off Transient
o
High Efficiency: 182mW at 34dBmV Out;
16mW in Transmit-Disable Mode
MAX3503
The MAX3503 programmable power amplifier is
designed for use in CATV upstream applications. The
MAX3503 drives 61dBmV (QPSK) into a 75Ω load when
driven with a 34dBmV nominal input signal. Both input
and output ports are differential, requiring that an exter-
nal balun be used at the output port. The variable gain
feature provides greater than 56dB of dynamic range,
which is controlled by an SPI™ 3-wire interface. Gain
control is available in 0.5dB steps. The device operates
over a frequency range of 5MHz to 65MHz. The
MAX3503 is internally matched for use with a 1:1 balun.
This device operates from a single 3.3V DC supply and
draws 235mA during transmit (100% duty cycle,
61dBmV out). The bias current is automatically
adjusted, based on the output level to increase efficien-
cy. Additionally, the device can be disabled between
bursts to minimize noise and save power while main-
taining a match at the output port. A shutdown mode is
available to disable all circuitry and reduce current con-
sumption to 5µA (typ).
The MAX3503 is available in a 20-pin QFN package.
The device operates in the extended industrial temper-
ature range (-40°C to +85°C).
Ordering Information
PART
MAX3503EGP
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
20 QFN-EP* (5mm
×
5mm)
*Exposed
pad.
________________________Applications
DOCSIS/EuroDOCSIS and DVB Cable
Modems
OpenCable Set-Top Box
Telephony Over Cable
CATV Status Monitor
V
CC
IN+
GND
IN-
GND
1
2
3
4
5
Pin Configuration
CEXT
N.C.
N.C.
N.C.
N.C.
TOP VIEW
GND
20
19
18
17
16
GND
15
14
13
V
CC
OUT+
N.C.
OUT-
N.C.
MAX3503
12
11
10
GND
GND
6
7
8
TXEN
9
Typical Operating Circuit appears at end of data sheet.
QFN**
SPI is a trademark of Motorola, Inc.
DOCSIS/EuroDOCSIS/OpenCable are trademarks of
CableLabs
®
.
**NOTE: CORNER GND PINS AND THE EXPOSED PAD MUST BE
SOLDERED TO THE SUPPLY GROUND.
________________________________________________________________
Maxim Integrated Products
SHDN
SCLK
SDA
CS
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.
Upstream CATV Amplifier
MAX3503
ABSOLUTE MAXIMUM RATINGS
V
CC
, OUT+, OUT-..................................................-0.5V to +6.5V
Input Voltage Levels (all inputs) .................-0.3V to (V
CC
+ 0.3V)
Continuous Input Voltage (IN+, IN-)....................................2V
P-P
Continuous Current (OUT+, OUT-) ...................................175mA
Continuous Power Dissipation (T
A
= +85°C)
20-Pin QFN (derate 27mW/°C above +85°C) .............1600mW
Operating Temperature Range .......................... -40°C to +85°C
Junction Temperature ..................................................... +150°C
Storage Temperature Range ............................ -65°C to +150°C
Lead Temperature (soldering, 10s) ................................ +300°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.
DC ELECTRICAL CHARACTERISTICS
(MAX3503 EV kit, V
CC
= 3.1V to 3.6V, V
GND
= 0, TXEN =
SHDN
= high, T
A
= -40°C to +85°C. Typical parameters are at V
CC
= 3.3V,
T
A
= +25°C, unless otherwise specified.) (Note1)
PARAMETER
Supply Voltage
Supply-Current Transmit Mode
Supply-Current Transmit Disable
Mode
Supply-Current Low-Power
Standby
LOGIC INPUTS
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
V
INH
V
INL
I
BIASH
I
BIASL
V
INH
= V
CC
V
INL
= 0V
-100
2
0.8
100
V
V
µA
µA
SYMBOL
V
CC
I
CC
I
CC
I
CC
D7 = 1, gain code = 115 (A
v
= 27dB)
D7 = 0, gain code = 92 (A
v
= 0dB)
TXEN = low
SHDN
= low
CONDITIONS
MIN
3.1
235
55
4.8
5
7
TYP
MAX
3.6
287
UNITS
V
mA
mA
µA
AC ELECTRICAL CHARACTERISTICS
(MAX3503 EV kit, V
CC
= 3.1V to 3.6V, V
GND
= 0, P
IN
= 34dBmV, TXEN =
SHDN
= high, T
A
= -40°C to +85°C. Typical parameters are
at T
A
= +25°C, unless otherwise specified.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
D7 = 1, gain code = 119, T
A
= 0°C to +85°C
D7 = 1, gain code = 99, T
A
= 0°C to +85°C
D7 = 1, gain code = 83, T
A
= 0°C to +85°C
Voltage Gain, f
IN
= 5MHz
A
V
D7 = 0, gain code = 112, T
A
= 0°C to +85°C
D7 = 0, gain code = 92, T
A
= 0°C to +85°C
D7 = 0, gain code = 72, T
A
= 0°C to +85°C
D7 = 0, gain code = 43, T
A
= 0°C to +85°C
Voltage Gain, f
IN
= 65MHz
A
V
D7 = 1, gain code = 119, T
A
= -40°C to
+85°C (Note 2)
MIN
27
17
9
8
-2
-12
-26.5
26.3
TYP
28.5
18.5
10.5
9.5
-0.5
-10.5
-25
MAX
30
20
12
11
1
-9
-23.5
dB
dB
UNITS
2
_______________________________________________________________________________________
Upstream CATV Amplifier
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX3503 EV kit, V
CC
= 3.1V to 3.6V, V
GND
= 0, P
IN
= 34dBmV, TXEN =
SHDN
= high, T
A
= -40°C to +85°C. Typical parameters are
at T
A
= +25°C, unless otherwise specified.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
V
OUT
= 61dBmV, f
IN
= 5MHz to 42MHz,
(Note 2)
Gain Rolloff
V
OUT
= 61dBmV, f
IN
= 5MHz to 65MHz,
(Note 2)
f
IN
= 5MHz to 65MHz, A
V
= -26dB to 27dB
Gain Step Size
f
IN
= 5MHz to 65MHz, A
V
= -26dB to 27dB,
any 2-bit transition of D0, D1
f
IN
= 5MHz to 65MHz, D7 = 0, gain code =
112, to D7 = 1, gain code = 83
Transmit-Disable Mode Noise
Isolation in Transmit-Disable
Mode
Transmit Mode Noise
Transmit Enable Transient
Duration
Transmit Disable Transient
Duration
TXEN = low, BW = 160kHz, f
IN
= 5MHz to
65MHz (Note 2)
TXEN = low, f
IN
= 5MHz to 65MHz (Note 2)
BW = 160kHz, f
IN
= 5MHz to 65MHz,
A
V
= -26dB to 27dB (Note 2)
TXEN input rise/fall time < 0.1µs,
T
A
= +25°C (Note 2)
TXEN input rise/fall time < 0.1µs,
T
A
= +25°C (Note 2)
D7 = 1, gain code = 115 (A
V
= 27dB),
T
A
= +25°C
Transmit Disable/Transmit Enable
Transient Step Size
D7 = 0, gain code = 83 (A
V
= 11dB),
T
A
= -40°C to +85°C
D7 = 0, gain code = 92 (A
V
= 0dB),
T
A
= +25°C
Input Impedance
Output Return Loss
Output Return Loss in Transmit-
Disable Mode
Z
IN
f
IN
= 5MHz to 65MHz, differential
(Note 2)
f
IN
= 5MHz to 65MHz, in 75Ω system, D7 = 1,
gain code = 119, (A
V
= 27dB)
f
IN
= 5MHz to 65MHz, in 75Ω system,
TXEN = low
3
2
10
10
kΩ
dB
dB
30
60
-55
2
2
80
20
mV
P-P
0.7
0.65
-1.1
0.5
1
1
1.3
1.35
-65
dBmV
dB
dBc
µs
µs
dB
-1.9
MIN
TYP
-0.6
MAX
-1.2
dB
UNITS
MAX3503
_______________________________________________________________________________________
3
Upstream CATV Amplifier
MAX3503
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX3503 EV kit, V
CC
= 3.1V to 3.6V, V
GND
= 0, P
IN
= 34dBmV, TXEN =
SHDN
= high, T
A
= -40°C to +85°C. Typical parameters are
at T
A
= +25°C, unless otherwise specified.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
Input tones at 42MHz and 42.2MHz, both
31dBmV, V
OUT
= 58dBmV/tone (Note 2)
Input tones at 65MHz and 65.2MHz, both
31dBmV, V
OUT
= 58dBmV/tone
2nd Harmonic Distortion
3rd Harmonic Distortion
HD2
HD3
f
IN
= 33MHz, V
OUT
= 61dBmV
f
IN
= 65MHz, V
OUT
= 61dBmV (Note 2)
f
IN
= 22MHz, V
OUT
= 61dBmV
f
IN
= 65MHz, V
OUT
= 61dBmV
MIN
TYP
-53
-49
-55
-55
-55
-55
-50
-50
-50
-50
dBc
dBc
MAX
-47
dBc
UNITS
Two-Tone Third-Order Distortion
IM3
TIMING CHARACTERISTICS
(V
CC
= 3.1V to 3.6V, V
GND
= 0V, TXEN =
SHDN
= high, D7 = 1, T
A
= +25°C, unless otherwise specified.) (Note 2)
PARAMETER
SEN-to-SCLK Rise Set Time
SEN-to-SCLK Rise Hold Time
SDA-to-SCLK Setup Time
SDA-to-SCLK Hold Time
SDA Pulse Width High
SDA Pulse Width Low
SCLK Pulse Width High
SCLK Pulse Width Low
SYMBOL
t
SENS
t
SENH
t
SDAS
t
SDAH
T
DATAH
T
DATAL
t
SCLKH
t
SCLKL
CONDITIONS
MIN
20
10
10
20
50
50
50
50
TYP
MAX
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
Note 1:
All parameters guaranteed by design and characterization to ±3 sigma for T
A
< +25°C, unless otherwise specified.
Note 2:
Guaranteed by design and characterization to ±6 sigma.
4
_______________________________________________________________________________________
Upstream CATV Amplifier
Typical Operating Characteristics
(Typical
Application Circuit,
V
CC
= 3.3V, V
IN
= 34dBmV, TXEN =
SHDN
= high, f
IN
= 20MHz, Z
LOAD
= 75Ω, T
A
= +25°C, unless oth-
erwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
MAX3503 toc01
MAX3503
SUPPLY CURRENT vs. GAIN CODE
390
360
330
300
270
240
210
180
150
120
90
60
30
0
0
MAX3503 toc02
VOLTAGE GAIN vs. SUPPLY VOLTAGE
HIGH-POWER MODE
GAIN CODE = 119
29.5
29.0
VOLTAGE GAIN (dB)
28.5
28.0
27.5
27.0
-40°C
+25°C
MAX3503 toc03
270
240
SUPPLY CURRENT (mA)
210
180
150
120
90
60
30
0
-50
-25
0
25
50
75
TRANSMIT-DISABLE MODE
TRANSMIT-ENABLE MODE,
LOW NOISE, GAIN CODE = 100
TRANSMIT-ENABLE MODE,
HIGH POWER, GAIN CODE = 119
30.0
SUPPLY CURRENT (mA)
HIGH-POWER MODE
LOW-NOISE MODE
26.5
26.0
20
40
60
80
100
120
140
2.9
3.0
3.1
+85°C
100
3.2
3.3
3.4
3.5
3.6
TEMPERATURE (°C)
GAIN CODE
SUPPLY VOLTAGE (V)
VOLTAGE GAIN vs. SUPPLY VOLTAGE
LOW-NOISE MODE
MAX3503 toc04
VOLTAGE GAIN vs. TEMPERATURE
HIGH-POWER MODE
MAX3503 toc05
VOLTAGE GAIN vs. TEMPERATURE
LOW-NOISE MODE
-8.2
-8.4
VOLTAGE GAIN (dB)
-8.6
-8.8
-9.0
-9.2
-9.4
-9.6
-9.8
-10.0
V
CC
= 3.0V
V
CC
= 3.6V
GAIN CODE = 80
V
CC
= 3.3V
MAX3503 toc06
-25.0
-25.5
-26.0
29.0
28.8
28.6
VOLTAGE GAIN (dB)
28.4
28.2
28.0
27.8
27.6
27.4
27.2
27.0
V
CC
= 3.6V
V
CC
= 3.0V
V
CC
= 3.3V
GAIN CODE = 119
-8.0
GAIN CODE = 43
VOLTAGE GAIN (dB)
-26.5
-27.0
-27.5
-28.0
-28.5
-29.0
2.9
3.0
3.1
-40°C
+25°C
+85°C
3.2
3.3
3.4
3.5
3.6
-40
-15
10
35
60
85
-40
-15
10
35
60
85
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
VOLTAGE GAIN vs. FREQUENCY
HIGH-POWER MODE
30
25
VOLTAGE GAIN (dB)
20
15
10
5
0
-5
-10
-15
1
D
GAIN CODE
A = 119, B = 99,
C = 82, D = 62
10
100
1000
-30
-40
1
B
C
A
MAX3503 toc07
VOLTAGE GAIN vs. FREQUENCY
LOW-NOISE MODE
MAX3503 toc08
VOLTAGE GAIN vs. GAIN CODE
35
30
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
-35
30
MAX3503 toc09
35
20
10
VOLTAGE GAIN (dB)
0
-10
C
-20
GAIN CODE
A = 112, B = 92,
C = 72, D = 43
10
100
D
A
B
HIGH-POWER MODE
VOLTAGE GAIN (dB)
LOW-NOISE MODE
1000
40 50 60
70 80 90 100 110 120
GAIN CODE
FREQUENCY (MHz)
FREQUENCY (MHz)
_______________________________________________________________________________________
5
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