NXP Semiconductors MC145483EN

Overview

MC145483EN from Freescale Semiconductor is a 13-bit linear 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, 2's complement data format, and integrated precision 0.886 V reference - used in digital telephony line interface circuits operating from a single 3 V supply.

For engineers reviewing the MC145483EN datasheet, MC145483EN pinout, MC145483EN application, or MC145483EN equivalent, key selection criteria include differential analog architecture for >75 dB dynamic range, synchronous/asynchronous clock support (FST/FSR up to 8 kHz), programmable receive gain control (0 to –21 dB), and power-down capability (<0.01 mW).

Technical Context

The MC145483EN implements fully-differential analog signal processing from TI+/TI– through switched-capacitor filters and 13-bit ADC/DAC, enabling 2× input amplitude headroom and common-mode noise rejection. Its transmit path includes active R-C pre-filtering, 5-pole anti-aliasing LPF, and bypassable 3rd-order HPF (200 Hz cutoff); receive path features sinX/X-compensated 5-pole LPF and active R-C post-filtering.

Digital interface supports Long/Short Frame Sync modes, sign-bit extended (16-bit) and receive-gain-adjust (16-bit with 3-bit attenuation code) synchronous operation, all driven by MCLK (256 kHz–4.096 MHz) with automatic prescaler detection. The VAG/VAG Ref architecture isolates analog ground from digital supply noise, critical for <1 LSB idle-channel noise performance.

Key Specifications

Pinout & Package

MC145483EN is packaged in 20-pin SOG (Case 751D), with pin-compatible variants in SSOP (940C) and TSSOP (948E). The SOG package provides robust thermal and EMI performance for voiceband analog signal integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV320AIC10IDBT and CS44600-CQZ, the MC145483EN delivers optimized voiceband performance with minimal BOM count - its integrated 200–3400 Hz filtering, HPF bypass, and VAG Ref architecture reduce PCB area and qualification effort for telephony line cards.

Availability

MC145483EN is available at Aetrix Electronics and suitable for telecom line card interface, DSP-based voice gateway, industrial voice alarm system, and secure radio baseband processor applications requiring stable component supply and long-term obsolescence management.

Supply support for MC145483EN 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) is a fabless semiconductor company specializing in mixed-signal and analog-intensive ICs for automotive, industrial, and communications markets.

The MC145483EN belongs to Freescale's legacy voiceband codec portfolio, designed specifically for cost-sensitive, high-reliability telephony infrastructure requiring single-supply operation and ITU-T compliance without external filtering.

FAQ

What is the primary function of the MC145483EN in a telephony system?

The MC145483EN serves as a complete analog front-end PCM codec-filter, performing voiceband analog-to-digital conversion (13-bit linear, 200 Hz–3.4 kHz), digital-to-analog reconstruction, and on-chip filtering - eliminating the need for external anti-aliasing, smoothing, and reference components in G.711-compliant systems. Its integrated 0.886 V reference and differential architecture ensure repeatable –5 dBm0 calibration across temperature and supply variations.

Does the MC145483EN support both synchronous and asynchronous clocking modes?

Yes, the MC145483EN supports both synchronous and asynchronous operation. FST and FSR can be aligned (synchronous) or independent (asynchronous) in Long/Short Frame Sync modes. The MCLK prescaler automatically detects 256 kHz–4.096 MHz inputs and generates internal 256 kHz sequencing - enabling flexible clock tree design without external dividers or PLLs in the MC145483EN system.

How does the HB pin affect the MC145483EN's transmit frequency response?

The HB (High-Pass Filter Bypass) pin on the MC145483EN controls whether the internal 3rd-order 200 Hz high-pass filter is enabled (HB = logic low) or bypassed (HB = logic high). When enabled, it attenuates 50/60 Hz power-line interference; when bypassed, the transmit path extends to DC - allowing use with piezoelectric sensors or DC-coupled microphone preamps without signal loss below 200 Hz.

What is the purpose of the VAG and VAG Ref pins on the MC145483EN?

The VAG pin provides a mid-supply (1.5 V) analog ground reference for all internal analog circuitry, while VAG Ref is a dedicated bypass node for the on-chip VAG generator. Connecting 0.1 µF ceramic capacitors from VAG Ref and VDD to VSS - with short, low-inductance traces - decouples switching noise from the analog core. This architecture reduces clock feedthrough by >20 dB compared to single-ground designs, directly improving MC145483EN SNR performance.

Can the MC145483EN drive a 600 Ω telephone line directly?

No, the MC145483EN's RO– output is rated for 2 kΩ loads, and its PO+/PO– push-pull drivers target 300 Ω. To drive a 600 Ω line, an external line driver (e.g., SLIC or transformer-coupled amplifier) is required. However, the MC145483EN's 0.886 V reference and –5 dBm0 calibration point are explicitly defined for 600 Ω impedance - ensuring accurate level setting when interfaced with compliant external drivers in the full MC145483EN signal chain.