Renesas ISL1557IRZ

Overview

ISL1557IRZ from Renesas Electronics is a dual current-feedback operational amplifier engineered for xDSL line driving in ADSL2+, VDSL2, and HDSL2 systems. It delivers 750mA output current from a single 4.5V–12V supply, achieves –80dBc distortion at 150kHz into 25Ω, and features C0/C1 bias control pins for dynamic power scaling. It targets 21dBm line driver applications in DSL customer premises equipment.

For engineers reviewing the ISL1557IRZ datasheet, ISL1557IRZ pinout, ISL1557IRZ application, or ISL1557IRZ equivalent, this page provides verified specifications, thermal-aware QFN package details, differential distortion performance across 4–17MHz, supply current modes (6–21.5mA per amp), and real-world DSL line driver implementation guidance - all confirmed against FN6568 Rev 3.00.

Technical Context

The ISL1557IRZ implements a dual current-feedback architecture optimized for high-speed DMT-based DSL signaling. Its bandwidth scales with feedback resistor value (e.g., 250MHz at RF = 750Ω, AV = +5) and remains stable across temperature due to minimal supply current drift. The device supports both single-supply (4.5V–12V) and split-supply (±2.25V–±6V) operation, with input common-mode range accommodating DC-biased or AC-coupled signal paths.

Two dedicated control pins (C0, C1) configure four bias states - full (12–21.5mA/amp), medium (11mA), low (6mA), and power-down (0.6–1.0mA) - enabling precise trade-offs between distortion, slew rate (750–1200V/µs), and thermal dissipation. Output clamps enhance lightning transient protection, critical for outdoor-facing DSL ports.

Key Specifications

Pinout & Package

ISL1557IRZ is housed in a thermally enhanced 16-lead 4×4mm QFN package (L16.4x4H) with exposed thermal pad. The pad must be connected to VS− for optimal thermal performance and ESD robustness. This package supports both single- and dual-supply configurations.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar xDSL line driver applications.

Compared with MAX13223EATA+ and THS6222IRGTR, the ISL1557IRZ uniquely balances 750mA drive, four-level bias control, integrated lightning protection, and 52°C/W thermal resistance - making it the only option qualified for production VDSL2 CPE meeting GR-1089-CORE surge immunity.

Availability

ISL1557IRZ is available at Aetrix Electronics and suitable for VDSL2 line driver modules, ADSL2+ customer premises equipment, and HDSL2 repeater designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for ISL1557IRZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Electronics is a global semiconductor leader specializing in microcontrollers, analog, and power solutions for industrial, automotive, and communications infrastructure.

The ISL1557IRZ belongs to Renesas' high-speed line driver product line, designed specifically for DSL physical layer (PHY) implementations requiring low distortion, programmable power, and robust surge tolerance in carrier-class access equipment.

FAQ

What is the maximum differential output voltage swing of the ISL1557IRZ?

The ISL1557IRZ delivers 20VP-P differential output swing into a 21Ω load when operating from ±6V supplies. This specification is confirmed in the "Features" section of FN6568 Rev 3.00 and enables compliance with 21dBm line power requirements in VDSL2 Class B deployments. The ISL1557IRZ maintains this swing across temperature and supply variations without external boost circuitry.

Does the ISL1557IRZ support single-supply operation?

Yes, the ISL1557IRZ supports single-supply operation from 4.5V to 12V, as explicitly stated in the "Supply Range" table on page 2 of FN6568 Rev 3.00. For proper operation, inputs must be DC-biased within the common-mode range or AC-coupled, and the thermal pad must be connected to VS−. The ISL1557AIRZ variant is validated for this configuration.

How do the C0 and C1 pins affect power consumption in the ISL1557IRZ?

The C0 and C1 pins configure four distinct bias states: full (12–21.5mA/amp), medium (11mA), low (6mA), and power-down (0.6–1.0mA). These settings directly scale quiescent current and output drive strength while preserving bandwidth above 200MHz in low-bias mode. The mapping is defined in Table "Electrical Specifications" on page 4 of FN6568 Rev 3.00.

What package type is used for the ISL1557IRZ, and why is thermal pad connection critical?

The ISL1557IRZ uses a 16-lead 4×4mm QFN package (L16.4x4H) with an exposed thermal pad. Per the "Pin Configurations" section on page 2 of FN6568 Rev 3.00, this pad must be connected to VS− to ensure safe dissipation of up to 2.4W. Failure to solder the pad results in junction temperature exceeding 150°C under 750mA load - triggering thermal shutdown or permanent damage.

Is the ISL1557IRZ RoHS compliant and lead-free?

Yes, the ISL1557IRZ is Pb-free and RoHS compliant, as confirmed in the "Features" list on page 1 and the "Ordering Information" table on page 2 of FN6568 Rev 3.00. It employs 100% matte tin plate (e3 termination finish) and meets IPC/JEDEC J-STD-020 reflow profiles for lead-free assembly.