NXP Semiconductors MC14LC5480EN

Overview

MC14LC5480EN from Freescale Semiconductor is a PCM codec-filter IC performing voice digitization and reconstruction with on-chip transmit band-pass (200 Hz–3.4 kHz) and receive low-pass (3.4 kHz) filtering, pin-selectable μ-law/A-law companding, and integrated 1.575 V precision reference voltage. It operates from a single 5 V supply with 15 mW typical power dissipation and supports synchronous/asynchronous timing modes including IDL, GCI, Short/Long Frame Sync.

For engineers reviewing the MC14LC5480EN datasheet, MC14LC5480EN pinout, MC14LC5480EN application, or MC14LC5480EN equivalent, key selection criteria include its fully differential analog signal path, 300 Ω push-pull power driver outputs, dual-clock domain support (FST/FSR), and compatibility with Motorola/Freescale telecom transceivers such as MC145472 and MC145422.

Technical Context

The MC14LC5480EN implements a differential switched-capacitor architecture for both encode and decode paths: the encoder uses a 5-pole switched-capacitor high-pass filter (200 Hz cutoff) followed by a 5-pole low-pass filter (3.4 kHz), while the decoder applies sinX/X-compensated 5-pole low-pass filtering and active R-C post-filtering. All analog processing-including the transmit gain op-amp (TI+/TI− → TG), autozeroed sample-and-hold, and bandgap-referenced successive-approximation ADC/DAC-is fully differential to suppress common-mode noise and double input dynamic range.

Digital interface flexibility is achieved via four timing modes: Long Frame Sync, Short Frame Sync, IDL (BCLKR = 1), and GCI (BCLKR = 0), each with distinct frame sync and bit clock relationships; MCLK accepts 256 kHz–4.096 MHz inputs and auto-prescales to generate internal 256 kHz sequencing clocks independent of data mode.

Key Specifications

Pinout & Package

MC14LC5480EN is packaged in a 20-pin SOG (Small Outline Gull-wing) package per Case 751D, with 0.3-inch body width and 0.050-inch lead pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PCM codec-filter applications.

Compared with MC145480P and TP3054CN, the MC14LC5480EN reduces total solution size by integrating reference, pre/post-filters, and power drivers-cutting bill-of-materials by up to 9 components per channel while supporting dual-law operation without hardware rework.

Availability

MC14LC5480EN is available at Aetrix Electronics and suitable for central office line cards, digital PBX interfaces, ISDN terminal adapters, and VoIP gateway FXS ports requiring stable component supply across extended product lifecycles.

Supply support for MC14LC5480EN 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

Freescale Semiconductor (now part of NXP Semiconductors) specialized in high-reliability analog-digital mixed-signal ICs for telecommunications infrastructure.

The MC14LC5480EN belongs to Freescale's legacy telecom codec family, designed specifically for voice digitization in PSTN access equipment, ISDN terminals, and digital switching systems compliant with ITU-T G.711.

FAQ

What is the primary function of the MC14LC5480EN in a telecom system?

The MC14LC5480EN serves as a complete PCM codec-filter, performing analog-to-digital conversion (A/D) with μ-law or A-law companding for voice digitization, and digital-to-analog conversion (D/A) with expansion for voice reconstruction. It integrates transmit band-pass (200 Hz–3.4 kHz) and receive low-pass (3.4 kHz) filtering, an on-chip 1.575 V precision reference, and 300 Ω push-pull power drivers-enabling direct connection to telephone line hybrids without external components. This makes the MC14LC5480EN ideal for central office line cards and digital PBX interfaces.

How does the MC14LC5480EN handle power management in low-power applications?

The MC14LC5480EN provides two independent power-down mechanisms: asserting logic low on the PDI (Pin 10) pin disables all internal clocks and bias currents, reducing power dissipation to 0.01 mW; alternatively, holding both FST and FSR pins low for several 8 kHz frames triggers automatic power-down. In either mode, outputs including RO+, RO−, PO+, PO−, TG, VAG, and DT enter high-impedance state. The MC14LC5480EN resumes normal operation within two FST cycles after PDI returns high, with DT remaining high-Z until filters settle-ensuring glitch-free startup.

Which digital interface modes does the MC14LC5480EN support, and how are they selected?

The MC14LC5480EN supports four industry-standard PCM timing modes: Long Frame Sync, Short Frame Sync, Interchip Digital Link (IDL), and Generic Circuit Interface (GCI). Mode selection is controlled by the logic state of BCLKR (Pin 9): high enables IDL mode, low enables GCI mode; Long/Short Frame Sync is auto-detected based on FST pulse width relative to BCLKT edges. All modes operate with 8 kHz frame sync and support bit clock frequencies from 64 kHz to 4.096 MHz. This flexibility allows the MC14LC5480EN to interface seamlessly with TI, Motorola, and LSI Logic framers and switch fabrics.

Can the MC14LC5480EN drive a standard telephone line directly?

Yes-the MC14LC5480EN features integrated push-pull 300 Ω power amplifier outputs (PO+ and PO−) capable of delivering 6.3 V_PP (±3.15 V) into a balanced 300 Ω load, meeting the +12 dBm line-driving requirement for analog telephone interfaces. External gain is set via resistors connected to PI (Pin 3), and the amplifiers can be independently powered down by tying PI to VDD. Because the MC14LC5480EN includes all required filtering and reference functions on-die, it eliminates the need for external line drivers, transformers, or voltage references-enabling direct connection to telephone hybrids in central office and PBX applications.

What is the significance of the fully differential analog design in the MC14LC5480EN?

The fully differential analog architecture in the MC14LC5480EN doubles the effective input dynamic range compared to single-ended designs-allowing ±3.15 V signals referenced to VAG-while rejecting common-mode noise injected through power supplies. This results in >60 dB improved power supply rejection ratio (PSRR) and enhanced immunity to board-level EMI. Differential processing extends from the TI+/TI− inputs through the switched-capacitor filters and ADC/DAC core to the RO+/RO− outputs, ensuring consistent noise performance across the entire signal chain. This design directly contributes to the MC14LC5480EN's ability to achieve 30 dB signal-to-distortion ratio over 42 dB dynamic range, satisfying ITU-T G.711 voice quality requirements.