Microchip Technology LE9541CUQCT

Overview

LE9541CUQCT from Microsemi is a single-channel high-voltage ringing SLIC (Subscriber Line Interface Circuit) designed for short-loop residential gateways interfacing with Broadcom BCM338x/BCM339x SoCs. It delivers –100 V ringing battery support (C-grade), DC loop closure, ring trip detection, thermal shutdown with hysteresis, and serial interface control - enabling voice loop feed, supervision, and wideband (up to 7 kHz) operation in cable-based VoIP systems.

For engineers reviewing the LE9541CUQCT datasheet, LE9541CUQCT pinout, LE9541CUQCT application, or LE9541CUQCT equivalent, key selection criteria include its 40-pin QFN package compatibility with Le9540 channel 1, GR909 test support, dual-threshold loop start/ring-ground detection, and integrated test load switch for algorithmic diagnostics.

Technical Context

The LE9541CUQCT implements a high-bandwidth analog front-end for voice line termination, featuring dedicated transmit/receive gain paths (G_TX = 150, G_RX = 13.67), longitudinal-to-metallic balance ≥52 dB, and PSRR ≥40 dB across 500 Hz–3 kHz in active modes. Its architecture supports both forward/reverse active states and ring state with distinct power consumption profiles per battery voltage grade.

Control and status reporting occur via a synchronous serial interface (DIN/CLK/DOUT/EN/RESET) with register-mapped configuration. The device integrates hardware-level protections including DC feed fault detection (RTFLT), thermal shutdown with hysteresis, and programmable thresholds for loop start, ring trip, and ring-ground events.

Key Specifications

Pinout & Package

LE9541CUQCT 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 LE9541DUQCT and LE9551CMQCT, the LE9541CUQCT provides optimal cost-performance balance for standard short-loop residential gateways: it shares the Le9540 layout while delivering verified –100 V ringing, GR909 compliance, and integrated test switching - eliminating redesign risk and external test components.

Availability

LE9541CUQCT is available at Aetrix Electronics and suitable for residential VoIP gateways, cable modem telephony adapters (EMTAs), and SOHO PBX systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant green packaging.

Supply support for LE9541CUQCT 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 LE9541CUQCT belongs to the VE950 Series SLIC product line, engineered specifically for broadband voice infrastructure applications requiring robust line interface performance, GR909 compliance, and seamless integration with Broadcom cable SoCs.

FAQ

What is the maximum ringing voltage supported by the LE9541CUQCT?

The LE9541CUQCT supports up to –100 V ringing battery voltage, as specified for the "C" grade variant. This rating is validated for no-load conditions and aligns with North American short-loop POTS line requirements. The device's ring-state power consumption is 211–236 mW at –100 V, confirming thermal viability under sustained operation. Do not operate LE9541CUQCT beyond this voltage, as higher ratings (e.g., –145 V) apply only to the LE9541DUQCT variant.

Is the LE9541CUQCT pin-compatible with the LE9540?

Yes, the LE9541CUQCT is explicitly designed as functionally equivalent to channel 1 of the LE9540 and shares identical 40-pin QFN package dimensions and pinout. Microsemi documentation confirms "pin-to-pin" compatibility to enable dual one- or two-channel PCB designs. This allows reuse of layout, routing, and thermal pad design from LE9540-based platforms without modification.

Does the LE9541CUQCT support GR909 testing?

Yes, the LE9541CUQCT supports GR909 testing through its integrated TLD (test load switch) terminal and serial interface control. Activation of the internal test load enables automated line diagnostics per Telcordia GR-909 Section 4.3.2 without external relays or switches. The device also provides RTFLT flag assertion and dual-threshold detection features required for full GR909 compliance verification.

What are the key differences between LE9541CUQCT and LE9551CMQCT?

The LE9541CUQCT uses a 40-pin 6×6 mm QFN package and supports –100 V ringing, while the LE9551CMQCT uses a smaller 28-pin 4×5 mm QFN and targets the same voltage grade. They are functionally equivalent single-channel SLICs but not pin-compatible. LE9551CMQCT reduces PCB area by ~40% but requires new layout; LE9541CUQCT preserves Le9540 design reuse. Both support GR909 and serial interface control.

How does the thermal shutdown with hysteresis work in the LE9541CUQCT?

The LE9541CUQCT implements thermal shutdown with hysteresis to prevent oscillation during overload. When junction temperature exceeds the trip threshold (typically ~150°C), the device disables output stages and asserts fault flags. It remains latched off until temperature falls below the hysteresis threshold (~20°C below trip), ensuring stable restart only after adequate cooling. This behavior is documented in the Product Brief and verified in thermal characterization data.