Renesas QLX4300SIQT7

Overview

QLX4300SIQT7 from Intersil is a quad-channel CML receive-side equalizer IC designed for high-speed serial interconnects, supporting line rates up to 3.125 Gb/s with 32-level programmable per-channel boost, 78 mW/channel power consumption, and <500 ps propagation delay. It compensates frequency-dependent loss in twin-axial copper cables up to 40 m (24 AWG) and enables InfiniBand SDR, 10GBase-CX4, and PCI Express Gen 1 applications.

For engineers reviewing the QLX4300SIQT7 datasheet, QLX4300SIQT7 pinout, QLX4300SIQT7 application, or QLX4300SIQT7 equivalent, key selection considerations include its 46-lead 4×7 mm QFN package, independent channel impedance select (IS pins), dual control modes (3-pin parallel or 4-wire serial), line-silence preservation capability, and CML I/O compatibility with 50 Ω differential termination.

Technical Context

The QLX4300SIQT7 implements four independent, settable analog equalizers followed by limiting amplifiers-each with configurable gain via either 3-bit CMOS control pins (CP[k][A,B,C]) or 5-bit serial register programming. Its signal-detect circuitry monitors equalized amplitude against a threshold set by the DT pin to enable automatic muting during electrical idle.

It supports two distinct operational modes: pin-controlled (18 of 32 boost levels) and serial-programmed (full 32 levels), with MODE pin selection and ENB/CLK/DI/DO interface compliant with 10–20 MHz CMOS timing. Input return loss exceeds 10 dB (differential, 50 MHz–3.75 GHz), and output residual jitter is 0.15–0.25 UI at 3.125 Gb/s after 20 m of 24 AWG cable.

Key Specifications

Pinout & Package

QLX4300SIQT7 is housed in a Pb-free 46-lead 4 mm × 7 mm QFN package with exposed thermal pad. Pin assignment follows Intersil's FN6982 Rev 1.00 specification, with dedicated CML I/O pairs, per-channel impedance select (IS1–IS4), detection threshold (DT), serial interface (DI/DO/CLK/ENB), mode control (MODE), and 3-bit boost control groups (CP1–CP4).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad-channel high-speed equalizer applications.

Compared with MAX3785ETJ+ and DS10BR150TSD/NOPB, QLX4300SIQT7 uniquely delivers full 3.125 Gb/s quad-channel equalization with protocol-aware line-silence preservation, dual-control flexibility, and CML-native I/O-making it the only drop-in solution for InfiniBand SDR and 10GBase-CX4 active cable reference designs.

Availability

QLX4300SIQT7 is available at Aetrix Electronics and suitable for InfiniBand SDR interconnects, 10GBase-CX4 active cable assemblies, and PCI Express Gen 1 board-to-board links requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for QLX4300SIQT7 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

Intersil Corporation (now part of Renesas Electronics) is a U.S.-based semiconductor company specializing in high-performance analog and mixed-signal ICs for communications, computing, and industrial markets.

The QLX4300SIQT7 belongs to Intersil's Quad Lane Extender product line, engineered specifically to extend reach and restore signal integrity in multi-gigabit copper-based serial protocols-including InfiniBand, 10GbE, and PCIe-without compromising protocol timing or electrical idle behavior.

FAQ

What is the maximum supported cable length for QLX4300SIQT7 at 3.125 Gb/s?

The QLX4300SIQT7 extends signal reach up to 40 m on 24 AWG twin-axial copper cable at 3.125 Gb/s. This performance is achieved using its 32-level per-channel equalization to compensate for frequency-dependent attenuation, validated per FN6982 Rev 1.00 test data with PRBS-7 patterns and Meritec-standard cabling.

Does QLX4300SIQT7 support both pin-strapping and serial programming for equalizer boost settings?

Yes, QLX4300SIQT7 supports dual configuration methods: (1) 3-bit parallel control via CP[k][A,B,C] pins for 18 of 32 boost levels, and (2) 5-bit serial register programming via DI/DO/CLK/ENB for all 32 levels. The MODE pin selects between them, and registers default to CP values on power-up per FN6982 Rev 1.00 Section 5.

How does QLX4300SIQT7 preserve line silence for InfiniBand and SAS protocols?

QLX4300SIQT7 preserves line silence using its DT (Detection Threshold) pin to set an amplitude threshold. When the equalized input signal falls below this threshold, the output driver is muted to nominal common-mode voltage-maintaining electrical idle for InfiniBand link training and SAS OOB signaling, as confirmed in FN6982 Rev 1.00 Sections 4 and 10.

What is the power consumption of QLX4300SIQT7 per channel, and how is it reduced during idle?

QLX4300SIQT7 consumes 78 mW per channel under active operation (260 mA total supply current). When a channel is powered down via its IS[k] pin, current draw drops from 50 mA to 3.8 mA-reducing total power by ~85% per disabled lane, as specified in FN6982 Rev 1.00 Electrical Specifications and Applications Information sections.

Is QLX4300SIQT7 compatible with CML I/O standards, and what termination is required?

Yes, QLX4300SIQT7 uses CML inputs and outputs with 50 Ω differential termination. Each IN[k]/OUT[k] pair requires 100 nF low-ESL/ESR MLCC AC coupling, and differential loads must be 50 Ω to achieve the specified 450–650 mV_P-P output swing and meet return loss targets (≥10 dB differential, 50 MHz–3.75 GHz), per FN6982 Rev 1.00 Pin Descriptions and Electrical Specifications.