Microchip Technology LE9541DUQCT

Overview

LE9541DUQCT 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 –145 V ringing battery support, 7-kHz wide-band operation, and serial interface control with reset, enabling loop start, ring trip, and thermal shutdown in voice loop supervision.

For engineers reviewing the LE9541DUQCT datasheet, LE9541DUQCT pinout, LE9541DUQCT application, or LE9541DUQCT equivalent, this device serves as a drop-in channel-level replacement for dual-channel PCB designs targeting GR909-compliant cable voice infrastructure with precise DC feed, ringing, and supervision functions.

Technical Context

The LE9541DUQCT implements a high-voltage analog front-end for voice line termination, integrating DC feed, ringing generation, and loop supervision in a single channel. Its architecture supports longitudinal-to-metallic balance ≥52 dB and PSRR ≥40 dB (500 Hz–3 kHz), ensuring noise immunity in active modes.

Control and status reporting occur via a synchronous serial interface (DIN/CLK/DOUT/EN/RESET) with programmable thresholds for loop start, ring trip, and ring-ground detection. Thermal shutdown includes hysteresis, and test load switching enables integrated GR909 compliance testing.

Key Specifications

Pinout & Package

LE9541DUQCT is housed in a 6×6 mm, 40-pin QFN package with exposed thermal pad. Pin assignment follows Microsemi's standardized layout for pin-to-pin compatibility with LE9540 channel 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LE9541CUQCT, LE9541DUQCT provides extended temperature operation without sacrificing performance or footprint; compared with LE9551DMQCT, it retains full LE9540 channel-1 pinout for legacy layout reuse but occupies larger board area.

Availability

LE9541DUQCT is available at Aetrix Electronics and suitable for residential cable gateways, VoIP terminals, and DSLAM voice modules requiring stable component supply and long-term industrial temperature support.

Supply support for LE9541DUQCT 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) designs high-reliability analog and mixed-signal semiconductors for aerospace, defense, communications, and industrial markets.

The LE9541DUQCT belongs to the VE950 Series SLIC family, engineered specifically for broadband voice infrastructure interfacing with Broadcom SoCs in short-loop cable and DSL access systems.

FAQ

What is the operating temperature range of the LE9541DUQCT?

The LE9541DUQCT is specified for industrial temperature operation from –40°C to +85°C. This extended range supports deployment in uncontrolled environments such as street cabinets or outdoor residential gateways. Its thermal shutdown circuit includes hysteresis to prevent cycling near the upper limit. The LE9541DUQCT maintains full electrical performance-including –145 V ringing capability and 52 dB longitudinal balance-across this entire range.

Is the LE9541DUQCT pin-compatible with the LE9540?

Yes, the LE9541DUQCT is pin-to-pin compatible with channel 1 of the LE9540 in the same 40-pin QFN package. This allows direct substitution in dual-channel PCB designs where only one channel is used, or enables flexible scaling between single- and dual-channel configurations without layout changes. The LE9541DUQCT shares identical pin assignments for VBAT, RINGP, ITR, DIN, CLK, DOUT, RESET, and TLD as documented in Figure 1 of the product brief.

Does the LE9541DUQCT support GR909 compliance testing?

Yes, the LE9541DUQCT supports GR909 testing through its integrated test load switch (TLD pin) and serial interface reporting. When activated, the internal test load enables verification of loop impedance, ring trip, and off-hook detection per Telcordia GR-909 Section 4.3. The device reports status via DOUT, allowing host SoCs like the BCM338x to automate pass/fail evaluation without external test equipment.

What is the maximum ringing voltage supported by the LE9541DUQCT?

The LE9541DUQCT supports up to –145 V ringing battery voltage, corresponding to the "D" suffix in its ordering code. This rating meets stringent requirements for long-loop ringing in North American residential cable gateways. The device sustains this voltage in ring state with power consumption of 312–359 mW (no load), and maintains ≥52 dB longitudinal balance to ensure signal integrity under high-voltage stress.

How does the LE9541DUQCT interface with Broadcom SoCs?

The LE9541DUQCT interfaces with Broadcom BCM338x and BCM339x SoCs via a synchronous serial control interface (DIN/CLK/DOUT/EN/RESET) and analog signal paths including TXI, RCVP, VTX, RINGP, and PT/PR. Reference schematics in the product brief show direct connection to BCM338x S_INTERFACE and VDDCORE domains. The LE9541DUQCT's gain settings (150× receive, 13.67× transmit) are optimized for these SoCs' ADC/DAC input ranges and noise floors.