The ISL1539A provides 4 internal wideband op amps

intended to be used as two pairs of differential line

drivers. The ISL1539A’s high bandwidth, 240MHz, and

ultra low distortion, -89dBc @ 1MHz, 2VP-P, support the

demanding MTPR requirements of emerging VDSL2 line

driver designs. Less demanding requirements can be met

at very low quiescent powers using the supply current

adjustment features.

Each of the 4 internal op amps is a wideband current

feedback amplifier offering very high slew rate intrinsic to

that design using low quiescent current levels. Each of

the two pair of amplifiers (ports) can also be power

optimized to the application using two external quiescent

control logic pins. Full power is nominally 27.2mA/port

with options of medium power cutback to 23mA/port, a

low power condition at 13.5mA/port, and an off state at

<0.5mA/port. Added quiescent power flexibility is

provided through an external IADJ pin. Grounding the pin

gives the nominal currents listed above while inserting a

resistor from this pin to ground can be used to scale each

of the settings downward.

High power push/pull line driver applications as

illustrated in the example below are best supported using

a low headroom, high output current device. On ±12V

supplies, the ISL1539A offers a 1.1V headroom with

>360mA peak output current. Driving differentially this

gives >41.8VP-P swing to as low as 58Ω differential load.

High SFDR operation is also supported for supplies as low

as ±7.5V. Intended to be used as differential pairs, this

two port device includes special circuitry to minimize

common mode loop peaking while also reducing the

common mode output noise spectrum. That circuitry

links the two sides of each port, precluding their

application as individual amplifiers.

特性 Features

? 360mA Output Drive Capability

? 41.8VP-P Differential Output Drive into 100Ω

? -89dBc THD @ 1MHz 2VP-P

? -65dBc MTPR (VDSL 8b Profile)

? High Slew Rate of 3000V/μs Differential

? Bandwidth (240MHz @ AV-DIFF = 10)

? Supply Current Control Pins

? Port Separation

- 78dB @ 500kHz

- 70dB @ 1MHz

- 60dB @ 4MHz

? Pb-Free (RoHS Compliant)

Applications

? 8MHz and 17MHz VDSL2 Profiles

? ADSL2+