STMicroelectronics TDA7479DTR

Overview

TDA7479DTR from STMicroelectronics is a single-chip RDS (Radio Data System) demodulator and 57 kHz bandpass filter for FM radio receivers, compliant with EBU specifications. It integrates an 8th-order switched-capacitor bandpass filter, digital RDS demodulation, ARI (Announcement Ready Indication) output, and RDS signal quality monitoring - all without external passive components. Used in automotive and consumer FM tuners to extract RDS data streams (RDDA) and clock (RDCL) for decoder interfacing.

For engineers reviewing the TDA7479DTR datasheet, TDA7479DTR pinout, TDA7479DTR application, or TDA7479DTR equivalent, key selection criteria include its 57 kHz filter center frequency, 1187.5 Hz RDCL clock output timing, 4.332 MHz crystal oscillator support, low-noise CMOS architecture, and dual-package availability (SO16/TSSOP16).

Technical Context

The TDA7479DTR implements a cascaded antialiasing + 8th-order switched-capacitor bandpass filter centered at 57 kHz (±0.5 kHz), delivering 3 kHz 3dB bandwidth and ≥50 dB attenuation at 38 kHz. Its purely digital demodulation section recovers RDDA and RDCL synchronized to the internal PLL, with data valid for 416.7 µs after each clock edge.

Configuration is managed via three control pins: FSEL selects crystal frequency (4.332/8.664/17.328 MHz), OSEL enables external oscillator drive (with ≤150 mVpp input), and TM activates test mode. All digital inputs feature internal pull-up (OSEL) or pull-down (FSEL, EXTRES, TM) resistors.

Key Specifications

Pinout & Package

Package: SO16 (ECOPACK® lead-free, wide-body, 10.5 mm × 7.6 mm). Pinout validated per STMicroelectronics datasheet Rev 8 (2013), Figure 2 and Table 2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si4702-A10 and TDA7332, the TDA7479DTR uniquely provides complete analog RDS baseband processing - from raw MPX input to synchronized RDDA/RDCL - in a single SO16 package with zero external filter components, making it optimal for analog tuner retrofits and cost-sensitive FM radio designs.

Availability

TDA7479DTR is available at Aetrix Electronics and suitable for automotive infotainment systems, consumer audio receivers, portable FM radios, and broadcast monitoring equipment requiring stable component supply and ECOPACK® compliance.

Supply support for TDA7479DTR 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, analog ICs, power management, and automotive-grade components.

The TDA7479DTR belongs to ST's audio signal processing product line, engineered specifically for high-fidelity, low-component-count RDS demodulation in cost-sensitive FM radio applications conforming to EBU standards.

FAQ

What crystal frequencies does the TDA7479DTR support?

The TDA7479DTR 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). The internal divider scales these to generate the precise 57 kHz filter clock and 1187.5 Hz RDCL output. External drive mode (OSEL = GND) accepts sinusoidal inputs at any of these frequencies with 60–150 mVpp amplitude.

How is RDS signal quality indicated on the TDA7479DTR?

Signal quality is reported on pin 1 (QUAL) as a logic-high output when the internal PLL achieves stable lock and RDS data integrity meets EBU thresholds. QUAL remains high during valid RDS reception and transitions low during loss of lock or insufficient MPX signal level (<1 mVrms). No external circuitry is needed - the output drives standard CMOS inputs directly.

Can the TDA7479DTR be used with an external 57 kHz filter?

No - the TDA7479DTR integrates a dedicated 8th-order switched-capacitor bandpass filter optimized for 57 kHz and expects the raw MPX signal (19+57 kHz) directly on pin 4 (MPX). Using an external 57 kHz filter would degrade performance by introducing phase distortion and insertion loss, and bypasses the IC's core value proposition of component reduction and guaranteed filter response.

What is the function of the EXTRES pin?

Pin 11 (EXTRES) is an active-high reset input. When left open, the device operates normally. When pulled to VS (5 V), it forces a hardware reset, clearing internal PLL states and reinitializing the demodulator and filter sections. This is used during power-up sequencing or recovery from loss-of-signal conditions to ensure deterministic startup behavior without relying on power-rail ramp timing.