General Description

The MAX9480/MAX9481/MAX9482 low-power, low-dis-

tortion, class-G, high-current asymmetric digital sub-

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.

Applications

Full-Rate ADSL

HDSL

Central Office

DSLAM

Features

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

(MAX9480/MAX9482)

Two Preamplifiers plus Class-G Rail-to-Rail

Buffers

Active Line Termination plus Integrated Hybrid

(MAX9480)

Low-Noise Uncommitted Receive Amplifiers

(MAX9482)

Fixed-Gain Receive Amplifiers (MAX9480)

Low-Output-Impedance Shutdown Mode

o Preamplifiers, Buffers, and Active Line

Termination Functions (MAX9481)

o High-Output-Drive Capability

Ω

500mA Output-Drive

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

Low-Power, Low-Distortion, Central-Office

ADSL Drivers and Integrated Drivers/Receivers

________________________________________________________________ Maxim Integrated Products

1

20

19

18

17

16

15

14

13

1

2

3

4

5

6

7

8

OUT1

RXP

IN1+

IN1-

POUT1

TOP VIEW

OUT2

IN2+

RXM

SHDN

DGND

12

11

9

10

POUT2

IN2-

MAX9480

TSSOP

Pin Configurations

Ordering Information

19-2539; Rev 1; 1/03

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.

PART

TEMP RANGE

PIN-PACKAGE

MAX9480CUP

-40

°C to +85°C

20 TSSOP-EP**

MAX9481CUP

-40

°C to +85°C

20 TSSOP-EP

MAX9482CUI

-40

°C to +85°C

28 TSSOP-EP

MAX9482CGJ*

-40

°C to +85°C

32 QFN

Typical Operating Circuits appear at end of data sheet.

Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.

Pin Configurations continued at end of data sheet.

*Future product—contact factory for availability.

**EP = Exposed pad.