NXP Semiconductors MC145483DWR2

Overview

MC145483DWR2 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 as analog front-end in T1/E1 line cards, digital PBX systems, and VoIP gateway voice interfaces.

For engineers reviewing the MC145483DWR2 datasheet, MC145483DWR2 pinout, MC145483DWR2 application, or MC145483DWR2 equivalent, key selection criteria include differential analog architecture for >75 dB dynamic range, synchronous/asynchronous clock support (FST/FSR up to 8 kHz), 3 V single-supply operation, and programmable receive gain control (0 dB to –21 dB in 3 dB steps).

Technical Context

The MC145483DWR2 implements fully-differential analog signal processing from TI+/TI– input through active R-C pre-filtering, differential switched-capacitor band-pass (200 Hz–3.4 kHz) and high-pass (bypassable via HB pin) filtering, and 13-bit successive-approximation ADC - all referenced to internal VAG mid-supply ground. Its DAC path reconstructs 13-bit 2's complement data using differential switched-capacitor sinX/X-compensated low-pass filtering followed by active R-C post-filtering.

Digital interface supports Long/Short Frame Sync modes, with BCLKR pin selecting between sign-bit-extended (16-bit) or receive-gain-adjust (13+3-bit) synchronous operation; MCLK accepts 256 kHz–4.096 MHz inputs and auto-prescales to generate internal 256 kHz sequencing clock for ADC/DAC and filter timing.

Key Specifications

Pinout & Package

MC145483DWR2 is housed in a 20-pin SOIC (SOG) package per Case 751D, with gull-wing leads, 0.65 mm pitch, and 7.5 mm × 12.8 mm body dimensions. Pin functions are validated per Freescale MC145483 datasheet Rev 3 (April 2003).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CS5321-KP and TLV320AIC10IPFB, the MC145483DWR2 uniquely integrates telephony-optimized analog filters, VAG-referenced differential architecture, and hardware-based receive gain control - making it the only option requiring zero external analog filtering components in G.711-compliant designs.

Availability

MC145483DWR2 is available at Aetrix Electronics and suitable for telecom infrastructure, digital PBX systems, and VoIP gateway designs requiring stable component supply, long-lifecycle support, and traceable sourcing for production ramp-up.

Supply support for MC145483DWR2 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 embedded processing, analog, and mixed-signal solutions for automotive, industrial, and communications markets.

The MC145483DWR2 belongs to Freescale's legacy telecom analog front-end product line, designed specifically for voice digitization in TDM-based digital switching systems - emphasizing low-noise differential architecture, single-supply operation, and ITU-T G.711 compliance.

FAQ

What is the function of the HB pin on the MC145483DWR2?

The HB (Transmit High-Pass Filter Bypass) pin on the MC145483DWR2 controls whether the internal third-order 50/60 Hz high-pass filter is enabled or bypassed in the transmit analog path. A logic low activates the filter for telephony applications requiring power-line interference rejection; a logic high bypasses it to allow DC-coupled or sub-200 Hz signal processing. This pin directly configures analog signal routing without firmware intervention, and its state is sampled asynchronously relative to frame clocks.

Does the MC145483DWR2 support both μ-law and A-law companding?

The MC145483DWR2 is a 13-bit linear PCM codec-filter and does not perform μ-law or A-law companding internally. Its 2's complement digital output is linear; companding must be implemented externally in the connected DSP or microcontroller. However, its calibration level (–5 dBm at 600 Ω, 0.436 Vrms) aligns with μ-law bit weighting, enabling straightforward software-based conversion to standard G.711 streams without gain mismatch or clipping risk.

How does the MC145483DWR2 achieve 75 dB dynamic range with a 3 V supply?

The MC145483DWR2 achieves >75 dB dynamic range through fully-differential analog design: differential signal processing doubles effective input swing, common-mode noise rejection suppresses supply-induced distortion, and auto-zeroed switched-capacitor filters minimize offset and drift. Combined with 13-bit resolution (theoretical 78 dB), precision 0.886 V reference, and optimized 2 kΩ load drive capability, this yields measured idle-channel noise below 1 LSB - verified in Freescale's characterization across temperature and supply voltage.

Can the MC145483DWR2 operate with asynchronous FST and FSR clocks?

Yes, the MC145483DWR2 supports fully asynchronous operation between FST (transmit frame sync) and FSR (receive frame sync), as confirmed in the functional description and timing diagrams (Figures 2a–2d). Each clock domain operates independently - FST controls DT output timing and transmit filter synchronization, while FSR governs DR input sampling and receive filter timing - enabling flexible integration with non-coordinated DSP subsystems or multi-processor architectures.

What is the purpose of the VAG and VAG Ref pins on the MC145483DWR2?

The VAG pin (Pin 20) provides a high-impedance mid-supply (1.5 V) analog ground reference for all internal analog circuitry, while VAG Ref (Pin 1) is its dedicated bypass node. A 0.1 µF capacitor from VAG Ref to VSS stabilizes the on-chip bandgap reference generator, isolating analog ground from digital supply noise. This dual-pin architecture prevents VSS-ground-referenced audio signals from injecting switching noise into the sensitive analog signal path - a key requirement for achieving <1 LSB noise performance.