STMicroelectronics E-TDA7478AD

Overview

E-TDA7478AD from STMicroelectronics is a single-chip RDS (Radio Data System) demodulator IC designed for FM radio receivers. It performs high-fidelity 57 kHz bandpass filtering and fully digital RDS data/clock recovery (RDDA and RDCL outputs), with integrated 4.332 MHz crystal oscillator support and signal quality indication (QUAL). Used in automotive and consumer FM tuners compliant with EBU specifications.

For engineers reviewing the E-TDA7478AD datasheet, E-TDA7478AD pinout, E-TDA7478AD application, or E-TDA7478AD equivalent, key selection criteria include its 57 kHz 8th-order switched-capacitor filter performance, RDS detection sensitivity (1 mV_RMS), dual crystal frequency support (4.332/8.664 MHz), and TSSOP16 package compatibility with space-constrained tuner designs.

Technical Context

The device implements a cascaded anti-aliasing + 8th-order switched-capacitor bandpass filter centered at 57 kHz (±0.4 kHz typical), delivering 22 dB attenuation at ±4 kHz offset and ≥60 dB rejection at 38 kHz. Its purely digital demodulation section recovers synchronized RDS data (RDDA) and 1187.5 Hz clock (RDCL) with 416.7 µs data hold time relative to clock edges.

Internal oscillator control is managed via FSEL (frequency select) and OSEL (oscillator enable) pins, enabling configuration for either 4.332 MHz or 8.664 MHz crystals-or external sinusoidal drive (≥60 mV_PP) with OSEL grounded. All input pins feature internal pull-up (OSEL) or pull-down (FSEL, TM, EXTRES) resistors.

Key Specifications

Pinout & Package

Package: TSSOP16 (3.0 × 4.4 mm, 0.65 mm pitch), RoHS-compliant ECOPACK® grade.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si4702-C10 and TDA7331, the E-TDA7478AD delivers superior analog front-end integration (no external filter), lower power (7.5 mA vs. 15 mA), and real-time hardware lock monitoring (QUAL), making it optimal for new FM tuner designs prioritizing component count reduction and deterministic timing.

Availability

E-TDA7478AD is available at Aetrix Electronics and suitable for automotive FM tuners, consumer stereo receivers, aftermarket car audio systems, and DAB/FM hybrid receivers requiring stable component supply and long-term production support.

Supply support for E-TDA7478AD 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, specializing in automotive, industrial, and consumer ICs with strong analog and mixed-signal design heritage.

The TDA7xxx series targets audio signal processing and broadcast demodulation, with the E-TDA7478AD specifically engineered to simplify RDS implementation in cost-sensitive, space-constrained FM radio systems.

FAQ

What crystal frequency should I use with E-TDA7478AD for standard RDS operation?

Use a 4.332 MHz fundamental-mode crystal with C1 = C2 = 27 pF for standard RDS operation. The device's internal divider generates the precise 57 kHz reference. Pin FSEL must be left open (internally pulled down) to select this frequency. An 8.664 MHz crystal is supported but requires FSEL tied to VS and is typically used in noise-sensitive layouts where higher fundamental frequency improves oscillator phase noise margin.

How does the QUAL output indicate RDS signal validity?

QUAL is an open-drain or CMOS output (per application circuit) that goes high when the internal PLL achieves stable lock on the 57 kHz RDS subcarrier and SNR exceeds threshold. It remains high during continuous valid reception and drops low during loss-of-lock events such as multipath fading or co-channel interference-enabling firmware to suppress invalid RDS data parsing.

Can E-TDA7478AD operate with an external 57 kHz clock instead of a crystal?

No-the device does not accept a direct 57 kHz clock. It requires either a 4.332 MHz or 8.664 MHz crystal (or external sine wave at those frequencies applied to OSCIN) to generate the internal 57 kHz reference via integer division. The T57 pin provides a buffered 57 kHz output for test purposes only and is not an input.

Is E-TDA7478AD qualified for automotive under-hood applications?

No-it is specified for −40 °C to +85 °C operating temperature and intended for passenger cabin or consumer indoor use. ST does not classify it as AEC-Q100 qualified. For under-hood deployment, consider the AEC-Q100 qualified TDA7478B variant (if available) or alternative automotive-grade RDS demodulators with extended temperature and qualification documentation.