The ISL1550 is a dual operational amplifier intended to be
used as a differential line driver. ISL1550’s high bandwidth
and low distortion performance enables the support of VDSL2
8b, 17a and 30a modem applications.
This device features a high current drive capability of ±750mA
required to drive large voltage peaks into heavy loads. In
Central Office (CO) applications, the driver achieves a typical
Missing Band Power Ratio (MBPR) of -66dBc in VDSL2 8b
upstream (US) 1 band and MBPR’s of -61dBc and -60dBc in
VDSL2 17a US1 and US2 respectively.
The ISL1550 has two bias current control pins (C0, C1) to allow
for four power settings (disable, low, medium, high). The VDSL
modem DSP configures the line driver’s power setting based
on the desired mode of operation. The line driver operates on a
nominal single +12V or a dual ±6V supplies with bias current
in active mode between 15mA to 32mA, depending on its
power setting. The ISL1550’s gain setting is configurable at
the application level by setting the Rf and Rg resistor values.
The surge current handling of ISL1550 has been enhanced to
allow ITU-T K.20 and GR1089 compliance with minimal
external surge protection circuitry.
The ISL1550 is available in the thermally-enhanced, Pb-free
RoHS compliant 16 Ld QFN package and is specified for
operation over the full -40°C to +85°C temperature range.

Features
• 20dBm output power capability
• Drives up to ±750mA from a +12V supply
• 18VP-P differential output drive into 20Ω
• -89dBc typical driver output distortion at full output at
200kHz, 12VP-P differential
• -61dBc US1, -60dBc US2 avg. MBPR 17a
• Supply range: ±4.0V to ±6.6V, +8.0V to +13.2V
• Thermal shutdown
• K.20, GR-1089 Surge Robustness Validated

Applications
• VDSL2 Profiles: 8MHz, 17MHz, and 30MHz