STMicroelectronics TDA7479ADTR

Overview

TDA7479ADTR from STMicroelectronics is a single-chip RDS (Radio Data System) demodulator and 8th-order 57 kHz bandpass filter for FM radio receivers, compliant with EBU specifications. It performs fully digital RDS demodulation without external components, delivers RDS data (RDDA) and clock (RDCL) outputs at 1187.5 Hz, and provides ARI indication and signal quality (QUAL) monitoring. Used in automotive and consumer FM tuners requiring embedded RDS decoding.

For engineers reviewing the TDA7479ADTR datasheet, TDA7479ADTR pinout, TDA7479ADTR application, or TDA7479ADTR equivalent, key selection criteria include its integrated 57 kHz filter performance (±0.5 kHz center tolerance, 3 kHz BW), oscillator flexibility (4.332/8.664/17.328 MHz options), low-noise CMOS design, and dual-package availability (TSSOP16).

Technical Context

The TDA7479ADTR implements a cascaded antialiasing + switched-capacitor 8th-order bandpass filter followed by a digital PLL-based biphase demodulator. Its architecture recovers RDS data (RDDA) and clock (RDCL) from the MPX composite signal while rejecting adjacent-channel interference via precise 57 kHz filtering.

It supports three crystal frequencies via FSEL pin configuration and allows external oscillator drive via OSEL pin to reduce EMI. The device outputs ARI status and QUAL signal quality indicators, with all inputs featuring internal pull-up/down resistors and outputs rated for 0.5 mA load.

Key Specifications

Pinout & Package

Package: TSSOP16 (ECOPACK®, lead-free, 5.0 mm × 4.4 mm body, 0.65 mm pitch).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RDS demodulator applications.

Compared with Si4702-C10-GM and TA2004F, the TDA7479ADTR offers the most direct, pin-compatible replacement for legacy MPX-fed RDS demodulator stages-retaining existing IF architecture while upgrading to digital filter stability and reduced EMI.

Availability

TDA7479ADTR is available at Aetrix Electronics and suitable for automotive infotainment modules, consumer FM receivers, and broadcast monitoring equipment requiring stable component supply and ECOPACK® compliance.

Supply support for TDA7479ADTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, mixed-signal, power, and microcontroller products for industrial, automotive, and consumer markets.

The TDA7479ADTR belongs to ST's audio signal processing product line, engineered specifically for high-fidelity, low-EMI RDS demodulation in cost-sensitive FM radio systems where analog MPX interface compatibility and minimal external components are critical.

FAQ

What crystal frequency should be used with TDA7479ADTR for standard RDS operation?

The default and most common configuration uses a 4.332 MHz crystal, selected by leaving FSEL pin open. This frequency is divided internally to generate the precise 57 kHz filter clock and 1187.5 Hz RDS clock. Alternative 8.664 MHz and 17.328 MHz crystals are supported via FSEL pin strapping for EMI optimization or layout constraints.

How does the QUAL output indicate RDS signal lock status?

The QUAL pin outputs a high logic level when the internal PLL achieves stable lock on the 57 kHz RDS subcarrier and valid data synchronization is established. It remains low or floats during acquisition, weak signal, or loss-of-lock conditions. No external pull-up is required as the output is actively driven.

Can TDA7479ADTR operate without a crystal?

Yes - when OSEL pin is pulled to GND, the internal oscillator is disabled and the device accepts an external 4.332/8.664/17.328 MHz sine wave on OSCIN with amplitude as low as 60 mV_PP. This mode reduces radiated emissions and allows use of low-phase-noise clock sources in noise-sensitive designs.

What is the purpose of the T57 pin and how is it used in system validation?

The T57 pin outputs a 57 kHz square wave derived from the internal bandpass filter clock, providing a direct observable reference for filter alignment and oscillator stability. Engineers use it with oscilloscopes or frequency counters during production test or field calibration to verify correct 57 kHz generation before enabling RDS data output.