STMicroelectronics E-TDA7479AD

Overview

E-TDA7479AD from STMicroelectronics is a single-chip RDS (Radio Data System) demodulator and 8th-order 57 kHz bandpass filter for FM radio receivers. It performs fully digital RDS signal recovery per EBU specifications, delivers synchronized 1187.5 Hz RDCL clock and parallel RDDA data outputs, and provides ARI (Announcement Radio Identification) and signal quality (QUAL) status flags. Used in automotive and consumer FM tuners requiring embedded RDS decoding.

For engineers reviewing the E-TDA7479AD datasheet, E-TDA7479AD pinout, E-TDA7479AD application, or E-TDA7479AD equivalent, this page details its integrated 57 kHz filtering, crystal oscillator options (4.332/8.664/17.328 MHz), low-noise CMOS architecture, and direct interface to external RDS decoders via TTL-compatible outputs.

Technical Context

The TDA7479 integrates a cascaded antialiasing + switched-capacitor 8th-order bandpass filter centered at 57 kHz (±0.5 kHz) with 3 dB bandwidth of 3 kHz and >22 dB attenuation at ±4 kHz offset. Its digital demodulation section extracts the biphase-decoded RDS data stream (RDDA) and recovers the 1187.5 Hz clock (RDCL) using dual PLLs - one for fast ARI detection and another for precise RDS timing synchronization.

Pin configuration enables flexible oscillator selection: FSEL sets crystal frequency (4.332/8.664/17.328 MHz), OSEL disables internal oscillator for external drive (60–150 mVpp), and TM/EXTRES support test mode and hardware reset. All inputs feature internal pull-up (OSEL) or pull-down (FSEL, TM, EXTRES) resistors.

Key Specifications

Pinout & Package

TSSOP16 package: 5.0 mm × 4.4 mm body, 0.65 mm pitch, 1.05 mm max height, lead-free ECOPACK® compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si4702-C10, E-TDA7479AD offers simpler analog interface and deterministic timing but lacks integrated ADC/DSP; compared with TDA7332, it eliminates manual tuning and improves RDS sensitivity by 6 dB while halving component count.

Availability

E-TDA7479AD is available at Aetrix Electronics and suitable for automotive infotainment systems, consumer stereo receivers, portable FM radios, and broadcast monitoring equipment requiring stable component supply and long-term lifecycle support.

Supply support for E-TDA7479AD 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 microcontrollers, power ICs, sensors, and analog chips for industrial, automotive, and consumer markets.

The TDA7xxx audio processing product line targets FM/AM radio subsystems, delivering integrated RDS, ARI, and audio signal conditioning functions optimized for cost-sensitive, high-reliability tuner applications.

FAQ

What crystal oscillator configurations does E-TDA7479AD support?

E-TDA7479AD supports three crystal frequencies: 4.332 MHz (default, FSEL open), 8.664 MHz (FSEL tied to VS), and 17.328 MHz (FSEL tied to GND). External drive mode (OSEL = GND) accepts 4.332/8.664/17.328 MHz sine inputs with 60–150 mVpp amplitude. C1 = 27 pF and C2 = 47 pF are recommended for 4.332 MHz operation.

How does the QUAL output indicate RDS signal validity?

The QUAL pin outputs logic high when the internal PLL achieves stable lock on the 57 kHz RDS subcarrier and the demodulated data meets minimum signal-to-noise criteria. It remains low during acquisition, weak signal conditions, or loss of lock. Host firmware must sample QUAL synchronously with RDCL edges to avoid metastability.

Can E-TDA7479AD operate without an external crystal?

No - E-TDA7479AD requires either a quartz crystal (4.332/8.664/17.328 MHz) connected between OSCIN and OSCOUT, or an external sinusoidal clock source (same frequencies) applied to OSCIN with OSEL grounded. The internal oscillator cannot be disabled without providing an alternative clock source.

What is the purpose of the FILOUT pin in system design?

FILOUT provides the filtered 57 kHz RDS subcarrier signal after the 8th-order switched-capacitor bandpass stage. It allows external verification of filter performance using oscilloscopes or spectrum analyzers, supports hybrid architectures where analog demodulation follows digital filtering, and enables diagnostic monitoring of MPX path integrity prior to digital decoding.