Microchip Technology LE9541CUQC

Overview

LE9541CUQC from Microsemi is a single-channel high-voltage ringing SLIC (Subscriber Line Interface Circuit) functionally equivalent to channel 1 of the LE9540, designed for short-loop residential gateways interfacing with Broadcom BCM338x/BCM339x SoCs. It delivers –100 V ringing battery support (C-grade), serial interface control with reset, GR909 test compliance, and DC loop closure/ring trip/thermal shutdown protection.

For engineers reviewing the LE9541CUQC datasheet, LE9541CUQC pinout, LE9541CUQC application, or LE9541CUQC equivalent, key selection considerations include its 40-pin QFN package compatibility with LE9540 channel 1, wide-band 7-kHz operation, dual-threshold loop supervision, and integrated test load switch for automated diagnostics in voice-over-cable systems.

Technical Context

The LE9541CUQC implements a high-voltage analog front-end for voice line supervision and ringing generation, featuring dedicated transmit/receive gain paths (G = 150 and G = 13.67), longitudinal-to-metallic balance ≥52 dB, and PSRR ≥40 dB across 500 Hz–3 kHz in active modes. Its serial interface supports bidirectional status reporting and configuration via DIN/CLK/DOUT/RESET signals.

It integrates real-time fault detection including ring-trip, loop-start, ring-ground, thermal shutdown with hysteresis, and RTFLT output for external monitoring. The device operates with VBAT up to –100 V (C-grade), VDD = 3.3 V, and uses internal current sensing (ITR/432) and bias references (VREF, IREF) for precision loop control.

Key Specifications

Pinout & Package

LE9541CUQC is housed in a 6×6 mm, 40-pin QFN package with exposed thermal pad. Pin assignment follows Microsemi's standardized layout for LE9540 channel 1 compatibility.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SLIC applications.

Compared with LE9541DUQC, the LE9541CUQC offers identical functionality at commercial temperature range, while LE9551CMQC trades pin compatibility for compactness-making LE9541CUQC optimal for legacy-compatible gateway upgrades where thermal margin and layout continuity are critical.

Availability

LE9541CUQC is available at Aetrix Electronics and suitable for residential cable gateways, Broadcom SoC-based VoIP terminals, and single-channel embedded voice nodes requiring stable component supply and long-term manufacturability.

Supply support for LE9541CUQC 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 Corporation (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog, mixed-signal, and RF solutions for aerospace, defense, communications, and industrial markets.

The LE9541CUQC belongs to the VE950 Series of ringing SLICs, engineered specifically for interoperability with Broadcom cable SoCs and compliance with GR909 test standards in short-loop voice infrastructure.

FAQ

What is the maximum ringing battery voltage supported by the LE9541CUQC?

The LE9541CUQC supports up to –100 V ringing battery voltage, designated as the "C" grade variant per Microsemi documentation. This rating ensures compatibility with standard POTS ringing requirements in residential cable gateway applications. Operation above –100 V is not specified for LE9541CUQC; the –145 V capability applies only to the LE9541DUQC (D-grade) variant. Always verify VBAT derating against ambient temperature in final design.

Is the LE9541CUQC pin-to-pin compatible with the LE9540?

Yes, the LE9541CUQC is pin-to-pin compatible with channel 1 of the LE9540, as explicitly stated in the product brief. Both use the same 6×6 mm 40-pin QFN package and share identical pin assignments for all functional signals-including VCC, VDD, VBAT, RINGP, RTFLT, DIN/CLK/DOUT, and RESET. This allows direct substitution in existing LE9540 channel 1 layouts without PCB modification.

Does the LE9541CUQC support GR909 testing?

Yes, the LE9541CUQC supports GR909 testing through its integrated test load switch (TLD) and serial interface. The device implements on-chip test algorithms that comply with Telcordia GR-909 requirements for loop diagnostics, including open/short detection and impedance verification. No external relays or test fixtures are needed when using the TLD control and RTFLT status reporting features of the LE9541CUQC.

What is the purpose of the RTFLT pin on the LE9541CUQC?

The RTFLT (Ring Trip Fault) pin on the LE9541CUQC is an open-drain output that asserts low during detected fault conditions-including thermal shutdown, overcurrent, ring-trip, or loop-open events. It serves as a real-time hardware interrupt to the host SoC, enabling immediate system-level response without polling. In the LE9541CUQC, RTFLT behavior is synchronized with internal status registers accessible via the serial interface for cross-verification.

How does the LE9541CUQC differ from the LE9551 series?

The LE9541CUQC differs from the LE9551 series primarily in package size, pin count, and design intent: LE9541CUQC uses a 40-pin QFN for LE9540 channel 1 compatibility, while LE9551CMQC uses a smaller 28-pin QFN optimized for new single-channel designs. Electrically, both deliver identical SLIC functionality and –100 V ringing, but LE9551 lacks pin compatibility and certain supervision thresholds present in LE9541CUQC's full feature set.