Low-Power / Low-Distortion / Central-Office ADSL Drivers and Integrated Drivers/Receivers
|Total Page||18 Pages|
|Features||Datasheet pdf 19-2539; Rev 1; 1/03 Low-Power, Low-Dis tortion, Central-Office ADSL Drivers an d Integrated Drivers/Receivers General Description The MAX9480/MAX9481/MAX9482 low-power, low-distortion, class-G, hi gh-current asymmetric digital subscribe r line (ADSL) drivers offer Rail-to-Rai l® output and are ideal for ADSL in ce ntral-office applications. Operating fr om ±5V and ±2.5V supplies, the driver s incorporate two high-speed current-fe edback preamplifiers driving two fixed- gain class-G buffers. The buffers can d eliver 20.4dBm average line power with a signal crest factor of 5.3, and are d esigned to be directly DC or AC bridged across a 1:2.5 transformer. The MAX948 0/MAX9481/MAX9482 employ an active line.|
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19-2539; Rev 2; 9/05
Low-Power, Low-Distortion, Central-Office
ADSL Drivers and Integrated Drivers/Receivers
The MAX9480/MAX9481/MAX9482 low-power, low-dis-
tortion, class-G, high-current asymmetric digital sub-
scriber line (ADSL) drivers offer Rail-to-Rail® output and
are ideal for ADSL in central-office applications.
Operating from ±5V and ±2.5V supplies, the drivers
incorporate two high-speed current-feedback preampli-
fiers driving two fixed-gain class-G buffers. The buffers
can deliver 20.4dBm average line power with a signal
crest factor of 5.3, and are designed to be directly DC or
AC bridged across a 1:2.5 transformer.
The MAX9480/MAX9481/MAX9482 employ an active line
termination scheme for incoming signals that eliminates
the need for back-match resistors, reducing line-card
power consumption at full rate to less than half of that
required by conventional class-AB line-driver circuits.
The MAX9480 includes a hybrid network and two low-
noise, fixed-gain-of-4.6V/V receive amplifiers. The part is
designed to recover the receive signal to the same level
as that of a conventional line interface circuit that incor-
porates a 1:2 transformer and standard back-matched
hybrid, without degrading signal-to-noise ratio (SNR) or
line-impedance sensitivity. The MAX9481 provides only
the preamplifiers and buffers without the hybrid or
receivers. The MAX9482 provides preamplifiers, buffers,
and uncommitted receive amplifiers. All devices have a
low-output-impedance shutdown function for saving
power when not transmitting.
At full-rate 20.4dBm discrete multitone data transmission
(DMT), the total dynamic power dissipation is only
680mW (MAX9480/MAX9482) or 655mW (MAX9481).
The MAX9480/MAX9481 are available in a 20-pin TSSOP
package and the MAX9482 is available in 28-pin TSSOP
and 32-pin QFN packages. All devices operate over the
extended -40°C to +85°C temperature range.
Typical Operating Circuits appear at end of data sheet.
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
o Dissipate Only 655mW While Driving 20.4dBm
ADSL Full-Rate DMT-Modulated Signal
o Operate with ±5.0V and ±2.5V Power Supplies
o Complete ADSL Central-Office Line Interface
Two Preamplifiers plus Class-G Rail-to-Rail
Active Line Termination plus Integrated Hybrid
Low-Noise Uncommitted Receive Amplifiers
Fixed-Gain Receive Amplifiers (MAX9480)
Low-Output-Impedance Shutdown Mode
o Preamplifiers, Buffers, and Active Line
Termination Functions (MAX9481)
o High-Output-Drive Capability
15VP-P Differential Output Voltage Swing at
RL = 16Ω
o Low Distortion: -71dBc Highest Harmonic at 1MHz
o High Speed: 250V/µs Slew Rate, 80MHz -3dB
Bandwidth (G = -3)
o Thermal Shutdown
o Exposed Pads Improve Thermal Performance
TEMP RANGE PIN-PACKAGE
MAX9480EUP -40°C to +85°C 20 TSSOP-EP** U20E-4
MAX9481EUP -40°C to +85°C 20 TSSOP-EP U20E-4
MAX9482EUI -40°C to +85°C 28 TSSOP-EP U28E-4
MAX9482EGJ* -40°C to +85°C 32 QFN
*Future product—contact factory for availability.
**EP = Exposed pad.
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products 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.