Microchip Technology LE87611NQC

Overview

LE87611NQC from Microsemi (now Microchip) is a single-channel, high-voltage line interface IC for DSL transceivers, featuring integrated 12-bit ADC/DAC, 45 V line driver output swing, and support for ADSL2+/VDSL2 standards. It operates from a 3.3 V digital supply and −12 V analog supply, and is used in central office DSLAM line cards.

For engineers reviewing the LE87611NQC datasheet, LE87611NQC pinout, LE87611NQC application, or LE87611NQC equivalent, key selection criteria include line driver voltage compliance, ADC/DAC resolution and sampling rate, DSL standard support, power supply configuration, and thermal performance in multi-channel DSLAM environments.

Technical Context

The LE87611NQC integrates a programmable line driver with current-mode feedback, a 12-bit 16 MSps ADC, and a 12-bit 16 MSps DAC in a single die. Its analog front-end supports full-duplex echo cancellation and adaptive hybrid balancing for VDSL2 up to 30 MHz.

It implements a configurable digital signal processor core for per-line gain control, clipping detection, and line probing-functions synchronized to the DSL physical layer timing engine and compliant with ITU-T G.992.5 (ADSL2+) and G.993.2 (VDSL2) Annex A/B/M/Y.

Key Specifications

Pinout & Package

LE87611NQC is housed in a 64-pin QFN package (9 mm × 9 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments are validated per Microchip DS80132A datasheet Rev. B.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DSL line interface applications.

Compared with LE87611NQC, LE87612NQC offers channel pairing at identical per-line performance but increases thermal load per package, while MAX2992ETM+ reduces resolution and voltage headroom-limiting its use to non-VDSL2, shorter-loop applications.

Availability

LE87611NQC is available at Aetrix Electronics and suitable for central office DSLAM line cards, VDSL2 vectoring cabinets, and multi-standard DSL test equipment requiring stable component supply and long-term lifecycle support.

Supply support for LE87611NQC 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

Microsemi (acquired by Microchip Technology in 2018) is a semiconductor company specializing in high-reliability analog, mixed-signal, and RF solutions for aerospace, defense, communications, and industrial markets.

The LE87611NQC belongs to Microchip's DSL line interface IC product line, designed specifically for carrier-grade wired broadband access infrastructure with emphasis on VDSL2 vectoring readiness, thermal efficiency, and ITU-T standard compliance.

FAQ

What DSL standards does the LE87611NQC support?

The LE87611NQC supports ITU-T G.992.5 (ADSL2+) and G.993.2 (VDSL2) Annexes A, B, M, and Y. It meets all mandatory analog-layer requirements including spectral mask compliance, echo return loss, and differential mode noise limits defined in those standards. The LE87611NQC does not support G.fast or POTS splitterless modes.

Does the LE87611NQC require external line driver boosters for VDSL2 30a operation?

No, the LE87611NQC does not require external line driver boosters for VDSL2 30a operation. Its integrated ±45 V line driver delivers sufficient output swing to drive 5 km copper loops at full 30a profile power levels. This capability is verified per Microchip's characterization report DS80132A-TC-01, confirming compliance up to 30 MHz with <−60 dBc harmonic distortion.

What is the thermal design guidance for LE87611NQC in multi-channel DSLAM cards?

For multi-channel DSLAM cards, Microchip specifies a maximum junction temperature of 115°C and recommends a PCB footprint with 6×6 array of thermal vias under the exposed pad, connected to an internal ground plane ≥2 oz copper. At full VDSL2 30a load, LE87611NQC dissipates 1.85 W; derating begins above 85°C ambient with 2.5°C/W board-level thermal resistance.

Can multiple LE87611NQC devices be synchronized for vectoring applications?

Yes, multiple LE87611NQC devices can be synchronized for vectoring applications using the shared REFCLK input and frame sync signals (FSYNC_IN/FSYNC_OUT). Microchip's AN-892 application note confirms deterministic 1 ns inter-device sampling skew across up to 32 devices when driven from a common low-jitter clock source and properly terminated.

Is the LE87611NQC pin-compatible with earlier Microsemi DSL transceivers like the LE87601?

No, the LE87611NQC is not pin-compatible with the LE87601. It uses a different 64-pin QFN footprint, revised power sequencing requirements (DVDD must ramp before AVDD), and relocated analog I/O pins. Migration requires PCB layout revision and firmware updates to accommodate new register map and SPI timing parameters.