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.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
