Microchip Technology LE9551CMQC

Overview

LE9551CMQC from Microsemi is a single-channel high-voltage ringing SLIC optimized for short-loop residential gateways interfacing with Broadcom BCM338x/BCM339x SoCs. It delivers –100 V ringing battery support, 7-kHz wide-band operation, serial interface control with reset, and integrated loop supervision including ring trip, loop start, and thermal shutdown with hysteresis.

For engineers reviewing the LE9551CMQC datasheet, LE9551CMQC pinout, LE9551CMQC application, or LE9551CMQC equivalent, key selection criteria include its 4×5 mm 28-pin QFN package, –100 V ringing capability, GR909 test compliance, DC feed + ringing + supervision integration, and serial interface timing requirements for voice loop control in cable gateway designs.

Technical Context

The LE9551CMQC implements a high-voltage analog front-end for voice line interface, featuring dual-path transmit/receive gain (150× and 13.67×), longitudinal-to-metallic balance ≥52 dB, and PSRR ≥40 dB over 500 Hz–3 kHz. Its architecture supports active, power-scan, and ring states with distinct quiescent power profiles.

Control and status reporting occur via a synchronous serial interface (DIN/CLK/DOUT/EN/RESET) with register-mapped configuration. The device integrates test load switching, RTFLT fault detection, and dual-threshold loop event detection (ring trip, loop start, ring-ground) for robust supervision in broadband voice applications.

Key Specifications

Pinout & Package

LE9551CMQC uses a 4×5 mm, 28-pin QFN package with exposed thermal pad. Pin functions are validated per Microsemi Product Brief Document ID# 153225 (Fig. 2).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LE9541CUQC and LE9551DMQC, the LE9551CMQC offers the smallest footprint and lowest cost for single-channel –100 V applications, trading voltage headroom and PCB flexibility for compactness and optimized power in short-loop deployments.

Availability

LE9551CMQC is available at Aetrix Electronics and suitable for residential cable gateways, broadband voice terminals, and DSLAM line cards requiring stable component supply, RoHS-compliant packaging, and long-term industrial availability.

Supply support for LE9551CMQC 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 LE9551CMQC belongs to the VE950 Series SLIC product line, designed specifically to provide integrated, standards-compliant analog line interface functionality for broadband residential and access network voice gateways.

FAQ

What is the maximum ringing battery voltage supported by the LE9551CMQC?

The LE9551CMQC is rated for –100 V ringing battery operation, as specified in the Microsemi Product Brief (Document ID# 153225). This rating applies to the "C" variant designation in the LE9551 family. Exceeding this voltage may compromise reliability or violate absolute maximum ratings. The LE9551CMQC must be used with appropriate external protection and thermal management under sustained ringing conditions.

Does the LE9551CMQC support GR909 compliance testing?

Yes, the LE9551CMQC supports GR909 compliance testing through its integrated test load switch (TLD pin) and register-controlled test modes accessible via the serial interface. The device implements required spectral masks and test sequences per GR909 Rev. 4, enabling automated validation of ringing waveform fidelity and harmonic content without external instrumentation.

How does the LE9551CMQC differ from the LE9541CUQC in terms of package and pin compatibility?

The LE9551CMQC uses a 4×5 mm 28-pin QFN package, while the LE9541CUQC uses a 6×6 mm 40-pin QFN. They are not pin-compatible. The LE9541CUQC is pin-compatible with channel 1 of the LE9540, but the LE9551CMQC has a distinct pinout optimized for single-channel space-constrained designs, as shown in Figure 2 of the official Product Brief.

What are the power consumption characteristics of the LE9551CMQC in active and ring states?

In active state (forward/reverse) at –60 V VBAT, the LE9551CMQC consumes 96–107 mW (typ/max). In ring state with no load at –100 V VBAT, it consumes 211–236 mW. These values define thermal design requirements and influence heatsink selection or airflow needs in densely packed gateway chassis where multiple LE9551CMQC devices operate simultaneously.

Which Broadcom SoC families is the LE9551CMQC specifically optimized to interface with?

The LE9551CMQC is explicitly optimized to interface with the Broadcom BCM338x and BCM339x families of SoCs, as confirmed in the Microsemi Product Brief. Reference schematics and bias resistor values (e.g., RVITR = 54.9 kΩ, RRCVP = 84.5 kΩ) are provided for seamless integration, ensuring correct gain matching, common-mode rejection, and timing alignment between the SoC's analog front-end and the LE9551CMQC's SLIC functions.