NXP Semiconductors MC145483SDR2

Overview

MC145483SDR2 from Freescale Semiconductor is a 13-bit linear PCM codec-filter IC designed for voice digitization and reconstruction in digital telephony systems. It integrates differential analog signal processing, on-chip transmit band-pass (200–3400 Hz) and receive low-pass (≤3400 Hz) filters, 2's complement data interface, and an internal 0.886 V precision reference voltage. It operates from a single 3 V supply with typical power dissipation of 8 mW and supports synchronous/asynchronous clocking modes.

For engineers reviewing the MC145483SDR2 datasheet, MC145483SDR2 pinout, MC145483SDR2 application, or MC145483SDR2 equivalent, key selection considerations include its fully differential analog architecture for >75 dB dynamic range, programmable receive gain control (0 to –21 dB in 3 dB steps), high-impedance VAG reference for noise-sensitive analog grounding, and compatibility with Long/Short Frame Sync PCM timing formats.

Technical Context

The MC145483SDR2 implements a successive-approximation ADC and linear DAC sharing a differential autozeroed bandgap reference and CDAC/RDAC structure. Its analog signal path uses active R-C pre-filtering, differential switched-capacitor filtering (5-pole LPF + 3-pole HPF), and autozeroed sample-and-hold stages - all referenced to the VAG mid-supply node.

Digital interface flexibility includes four operational modes: Long Frame Sync, Short Frame Sync, sign-bit extended (16-bit transfers), and receive gain adjust (13-bit voice + 3-bit attenuation control). The MCLK prescaler automatically detects and adapts to eight standard frequencies (256 kHz to 4.096 MHz) to generate the internal 256 kHz sequencing clock.

Key Specifications

Pinout & Package

MC145483SDR2 is packaged in a 20-pin SSOP (Small Outline Package), case 940C, with 0.65 mm lead pitch and exposed pad for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV320AIC10IPFB and CS44600-CQZ, the MC145483SDR2 uniquely combines 13-bit linear voiceband performance, integrated analog filters, on-chip reference, and hardware-configurable HPF in a single 3 V, low-power SSOP package - making it purpose-built for cost-sensitive, standards-compliant telephony endpoints.

Availability

MC145483SDR2 is available at Aetrix Electronics and suitable for VoIP gateways, digital PBX line cards, wireless base station modems, and industrial voice recorders requiring stable component supply and long-lifecycle support.

Supply support for MC145483SDR2 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 MC145483SDR2 belongs to Freescale's legacy voiceband codec product line, engineered specifically for digital telephony infrastructure where integration, low power, and ITU-T G.711 compliance are critical.

FAQ

What is the function of the HB pin on the MC145483SDR2?

The HB (Transmit High-Pass Filter Bypass) pin on the MC145483SDR2 controls whether the internal third-order 50/60 Hz rejection filter is enabled or bypassed. A logic low activates the filter for standard telephony applications; a logic high removes it from the signal path, extending the transmit frequency response down to DC. This allows the MC145483SDR2 to support non-telephony audio sources such as sensors or DC-biased transducers without modification to the analog front-end.

Does the MC145483SDR2 require an external voltage reference?

No, the MC145483SDR2 does not require an external voltage reference. It integrates a precision autozeroed bandgap reference generating 0.886 V, which sets the –5 dBm TLP at 600 Ω and serves both the ADC and DAC sections. The VAG Ref (Pin 1) is provided solely for capacitive bypassing of the internal reference generator - no external reference component is needed for compliant operation.

How does the MC145483SDR2 achieve its 75 dB dynamic range?

The MC145483SDR2 achieves >75 dB dynamic range through a combination of fully differential analog signal processing, autozeroed comparator architecture, 5-pole switched-capacitor filtering, and optimized noise floor design. Its differential topology rejects common-mode supply noise, while the active R-C pre-filtering and sinX/X-compensated reconstruction filter minimize aliasing and out-of-band energy - resulting in typical idle channel noise below one LSB (≈216 µV).

Can the MC145483SDR2 operate with asynchronous transmit and receive clocks?

Yes, the MC145483SDR2 supports asynchronous operation between transmit and receive paths. The FST (transmit frame sync) and FSR (receive frame sync) pins accept independent 8 kHz clocks, and the BCLKR pin can be used asynchronously in Long or Short Frame Sync modes. This allows flexible integration with DSPs or microcontrollers that generate separate timing domains for upstream and downstream voice channels - a capability confirmed in the device's functional description and timing diagrams.

What is the role of the VAG and VAG Ref pins on the MC145483SDR2?

The VAG pin (Pin 20) provides a mid-supply analog ground (1.5 V) referenced to VSS and serves as the common-mode reference for all analog circuitry. The VAG Ref pin (Pin 1) is a dedicated bypass node for the internal VAG generator circuitry and must be decoupled to VSS with a 0.1 µF ceramic capacitor. Both pins are essential for minimizing noise coupling between digital switching and sensitive analog sections - and the VAG pin transitions to high-impedance during power-down to isolate the analog domain.