MAX9481

19-2539; Rev 1; 1/03 Low-Power, Low-Distortion, Central-Office ADSL Drivers and Integrated Drivers/Receivers General Description The MAX9480/MAX9481/MAX9482 low-power, low-distortion, class-G, high-current asymmetric digital subscriber 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 preamplifiers 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 lownoise, 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 incorporates 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 shut...