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NXP Semiconductors MC145484DW
- Part No.:
- MC145484DW
- Manufacturer:
- NXP Semiconductors
- Category:
- CODECS
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MC145484DW.pdf
- Description:
- IC CODEC PCM FILTER 13B 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,751
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Product details
Overview
MC145484DW from Freescale Semiconductor is a 5 V single-supply PCM codec-filter IC performing voice digitization and reconstruction with pin-selectable μ-law or A-law companding, on-chip 200 Hz–3.4 kHz band-pass (transmit) and 3.4 kHz low-pass (receive) filters, and integrated 1.575 V precision reference voltage. It serves as the analog front-end in telephony line interface circuits, supporting SLIC interfacing and ISDN U-interface applications.
For engineers reviewing the MC145484DW datasheet, MC145484DW pinout, MC145484DW application, or MC145484DW equivalent, key selection criteria include its differential analog architecture for noise immunity, 8 kHz frame sync compatibility across Long/Short Frame Sync, IDL, and GCI modes, power-down capability (<0.01 mW), and push-pull 300 Ω driver outputs for telephone line driving.
Technical Context
The MC145484DW implements a fully-differential analog signal path: transmit input passes through an active R-C pre-filter, single-ended-to-differential converter, 5-pole switched-capacitor band-pass filter (200 Hz–3.4 kHz), and differential compressing ADC; receive path uses differential DAC, sinX/X-compensated 5-pole switched-capacitor low-pass filter (3.4 kHz), active R-C post-filter, and buffered RO– output.
Digital interface supports four timing modes-Long Frame Sync, Short Frame Sync, IDL (BCLKR = 1), and GCI (BCLKR = 0)-with automatic MCLK prescaling for 256 kHz–4.096 MHz inputs, and independent FST/FSR frame sync handling. Power-down is triggered either by logic-low PDI or simultaneous low assertion of FST and FSR.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | Single 5 V rail; enables direct integration into legacy telephony power domains without dual supplies. |
| Power Dissipation | 15 mW typical active; 0.01 mW in power-down - reduces thermal load in dense line-card designs. |
| Companding Law | PIN-selectable μ-law (TI+ = VDD) or A-law (TI+ = VSS); eliminates firmware configuration overhead. |
| Reference Voltage | 1.575 V internal precision reference - sets –0 dBm TLP at 600 Ω, enabling calibrated audio level alignment. |
| Transmit Filter BW | 200 Hz to 3.4 kHz band-pass - meets ITU-T G.712 amplitude response requirements for voiceband transmission. |
| Receive Filter BW | 3.4 kHz low-pass with sinX/X compensation - suppresses aliasing images while preserving voice fidelity. |
| Driver Output | Push-pull PO+/PO– capable of 3.15 V peak into 300 Ω - delivers +12 dBm line drive compliant with SLIC interface specs. |
Pinout & Package
MC145484DW is housed in a 20-pin SOG (Small Outline Gull-wing) package per Case 751D, optimized for surface-mount assembly and thermal performance in telecom line cards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (6) | Positive supply | 5 V main power rail; requires local 0.1 µF ceramic decoupling to VSS for analog stability. |
| VSS (15) | Negative supply / digital ground | 0 V reference for digital logic and bias networks; separate from analog ground (VAG). |
| VAG (20) | Analog ground output | Mid-supply (2.5 V) reference for all analog circuitry; high-impedance in power-down mode. |
| VAG Ref (1) | VAG generation bypass | Bypass node for internal VAG generator; must be decoupled to VSS with 0.1 µF capacitor using low-inductance layout. |
| Mu/A (16) | Companding law select | Logic-high → μ-law; logic-low → A-law; determines encoder compression and decoder expansion algorithm. |
| PDI (10) | Power-down control | Active-low enable; gates clocks and bias currents, placing RO–, PO+, PO–, TG, DT, and VAG in high-impedance state. |
| TI+ (19), TI– (18) | Transmit input differential pair | FET-input op-amp terminals; support level-shifting for VSS-referenced signals and multiplexer selection of TG or TI– as filter input. |
| TG (17) | Transmit gain amplifier output | Drives 2 kΩ load; connects to anti-aliasing pre-filter; high-impedance when TI+ tied to VDD. |
| RO– (2) | Receive analog output (inverting) | Differential output of smoothing filter; drives 2 kΩ load to VAG; high-impedance in power-down. |
| PI (3), PO– (4), PO+ (5) | Power amplifier interface | Inverting op-amp input (PI) and push-pull outputs (PO–/PO+) form adjustable-gain line driver; PI = VDD disables driver. |
| MCLK (11), FST (14), BCLKT (12), DT (13) | Transmit digital interface | Supports 256 kHz–4.096 MHz MCLK; 8 kHz FST; 64 kHz–4.096 MHz BCLKT; serial PCM output on DT. |
| FSR (7), BCLKR (9), DR (8) | Receive digital interface | FSR accepts 8 kHz sync; BCLKR configures IDL/GCI mode; DR latches serial PCM data under BCLKR/FSR control. |
Key Features
| Feature | Design Value |
|---|---|
| Fully-differential analog design | Doubles allowable input amplitude vs. single-ended, rejects common-mode supply noise, and improves PSRR by >60 dB. |
| On-chip transmit/receive filters | Eliminates external passive LC or ceramic filters - reduces BOM count and board area in line interface units. |
| Active R-C pre- and post-filtering | Suppresses out-of-band energy before and after switched-capacitor filtering, minimizing harmonic distortion and clock feedthrough. |
| Pin-selectable μ-law/A-law | Enables global deployment without PCB revision - North America/Japan (μ-law) and Europe (A-law) variants use identical hardware. |
| High-impedance VAG reference | Allows clean separation of analog ground from noisy digital VSS, critical when external analog signals are VSS-referenced. |
| SLIC-optimized interface | RO–, PO+/PO–, and TI+/TI– pin assignments match standard electronic SLIC signal routing, simplifying interconnect design. |
Applications
| Electronic SLIC Interface | ISDN U-Interface Terminal |
|---|---|
Use Scenario: Connecting analog telephone handsets or fax machines to digital ISDN U-interface transceivers (e.g., MC14LC5472) in customer premises equipment. IC Role / Device Role / Timing Role: MC145484DW acts as the voiceband codec between the SLIC's analog port and the U-interface transceiver's digital PCM bus, providing μ-law/A-law conversion synchronized to 8 kHz FST/FSR. Use Value: Enables full-duplex voice transmission over 2B+D ISDN lines with <30 dB THD+N and compliance to ITU-T G.712 spectral mask via integrated band-limiting filters. | Use Scenario: Implementing the analog front-end in ISDN NT1 devices that terminate the U-interface and convert between 2B+D framing and analog voice channels. IC Role / Device Role / Timing Role: MC145484DW serves as the PCM codec in the analog section, interfacing directly with MC145572 U-interface transceivers using IDL timing mode (BCLKR = 1), with MCLK derived from system clock. Use Value: Delivers guaranteed –0 dBm TLP calibration via on-chip 1.575 V reference, ensuring consistent signal levels across multiple ISDN ports without external trimming. |
| Central Office Line Card | Digital PBX Voice Port |
Use Scenario: Integrating voice channel processing into carrier-grade line cards supporting 32+ subscriber lines per card. IC Role / Device Role / Timing Role: MC145484DW operates in Long Frame Sync mode with centralized 8 kHz FST distribution, digitizing analog loop-start/POTS signals for time-division multiplexing onto T1/E1 backplane. Use Value: Low 15 mW power dissipation allows high-density packaging; power-down (PDI) enables selective channel shutdown during idle periods to reduce total card power. | Use Scenario: Providing voice channel interfaces in enterprise digital PBX systems requiring analog station port expansion. IC Role / Device Role / Timing Role: MC145484DW functions as the codec in hybrid analog/digital port modules, accepting VSS-referenced handset signals and delivering PCM to the PBX's DSP fabric via Short Frame Sync timing. Use Value: High-impedance VAG output and dedicated VAG Ref pin minimize ground-loop noise when interfacing with legacy analog telephones sharing common VSS return paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PCM codec-filter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC145572DW | U-interface transceiver (not codec); lacks ADC/DAC, filters, and companding - requires external codec. | Designed for direct U-interface physical layer connection only; cannot replace MC145484DW's voiceband signal processing function. | Select MC145572DW only when pairing with a discrete codec; not a functional substitute for MC145484DW. |
| TP3067CP | Pin-compatible 20-pin DIP codec; supports μ-law only; no A-law selection; higher 30 mW active power; no VAG Ref pin. | Legacy replacement in through-hole designs; lacks VAG decoupling flexibility and dual-law support needed for multi-region deployments. | Choose TP3067CP only for cost-sensitive, μ-law-only, non-SLIC applications where VAG noise isolation is not critical. |
Compared with MC145484DW, MC145572DW provides physical-layer U-interface signaling but no voiceband conversion, while TP3067CP offers μ-law-only operation with higher power and reduced analog grounding control - making MC145484DW uniquely suited for SLIC-coupled, globally deployable, low-noise telephony designs.
Availability
MC145484DW is available at Aetrix Electronics and suitable for electronic SLIC interfaces, ISDN U-interface terminals, central office line cards, digital PBX voice ports, and telecom infrastructure requiring stable component supply with long-lifecycle support.
Supply support for MC145484DW 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 automotive, industrial, and networking solutions with strong heritage in telecommunication ICs.
The MC145484DW belongs to Freescale's legacy telephony codec-filter product line, designed specifically for voiceband signal conditioning in SLIC-based line interface circuits and ISDN terminal equipment.
FAQ
What is the primary function of the MC145484DW in a telephony system?
The MC145484DW performs end-to-end voiceband signal conversion: it digitizes analog voice signals using a differential compressing ADC with μ-law or A-law companding, applies transmit band-pass (200 Hz–3.4 kHz) and receive low-pass (3.4 kHz) filtering, and reconstructs analog voice from PCM data via a differential DAC. Its role is to serve as the analog front-end in SLIC-coupled line cards and ISDN terminal equipment, ensuring ITU-T G.712-compliant voice transmission.
How does the MC145484DW handle analog ground referencing for mixed-signal layouts?
The MC145484DW uses a dedicated high-impedance VAG (Pin 20) output referenced to mid-supply (2.5 V), decoupled via VAG Ref (Pin 1) to VSS. This separates analog signal processing from noisy digital ground (VSS), reducing clock feedthrough when external analog signals are VSS-referenced. All internal analog circuitry - including TI+, TI–, RO–, and PO+/PO– - is referenced to VAG, not VSS.
Which digital interface modes does the MC145484DW support, and how are they selected?
The MC145484DW supports four PCM timing modes: Long Frame Sync, Short Frame Sync, IDL (BCLKR = 1), and GCI (BCLKR = 0). Mode selection is automatic based on FST/FSR pulse width and BCLKR logic state - no register writes required. Long/Short Frame Sync are detected by counting falling edges of BCLKT relative to FST; IDL/GCI are selected by holding BCLKR high or low, respectively.
Can the MC145484DW drive a standard 600 Ω telephone line directly?
No - the MC145484DW's PO+/PO– outputs are specified for 300 Ω loads at +12 dBm (3.15 V peak), optimized for SLIC interface rather than direct 600 Ω termination. To drive a 600 Ω line, an external line transformer or impedance-matching network is required. The device's 300 Ω drive capability matches industry-standard SLIC analog port specifications, not legacy POTS line impedances.
What is the significance of the 1.575 V on-chip reference voltage in the MC145484DW?
The 1.575 V precision reference sets the –0 dBm transmission level point (TLP) at 600 Ω, enabling accurate calibration of voice signal levels without external components. It stabilizes ADC/DAC full-scale ranges and filter cutoffs against temperature and supply variation, ensuring consistent voice quality and compliance with ITU-T G.711 companding standards across operating conditions.
MC145484DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- PCM, Filter
- Data Interface:
- PCM Audio Interface
- Resolution (Bits):
- 13 b
- Number of ADCs / DACs:
- 1 / 1
- Sigma Delta:
- No
- S/N Ratio, ADCs / DACs (db) Typ:
- -
- Dynamic Range, ADCs / DACs (db) Typ:
- -
- Voltage - Supply, Analog:
- -
- Voltage - Supply, Digital:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
MC145484DW FAQ
1.How can I place an order for MC145484DW through Aetrix?
Please submit a Request for Quotation (RFQ) for MC145484DW on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MC145484DW reliable?
The price and inventory of MC145484DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC145484DW is usually 5 days.
3.What payment methods are accepted for MC145484DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC145484DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC145484DW?
MC145484DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC145484DW order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MC145484DW?
For technical support, including MC145484DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC145484DW requirements.
6.How does Aetrix verify that MC145484DW is sourced from the original manufacturer or authorized distributors?
All MC145484DW products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MC145484DW meets industry standards.
7.What is the process for return or replacement of MC145484DW?
All MC145484DW units undergo pre-shipment inspection (PSI). If there is an issue with MC145484DW, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MC145484DW part is unused and in its original packaging.
Return procedure for MC145484DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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