STMicroelectronics E-TDA7478ADTR

Overview

E-TDA7478ADTR 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 extraction, delivering validated RDDA data and RDCL clock outputs with 1187.5 Hz frequency. The device integrates an on-chip 4.332 MHz crystal oscillator (8.664 MHz optional), operates from 4.5–5.5 V, and targets automotive and consumer FM tuners compliant with EBU specifications.

For engineers reviewing the E-TDA7478ADTR datasheet, E-TDA7478ADTR pinout, E-TDA7478ADTR application, or E-TDA7478ADTR equivalent, key selection criteria include its 8th-order switched-capacitor filter performance, RDS signal quality output (QUAL), oscillator configuration flexibility via FSEL/OSEL pins, and TSSOP16 package compatibility with space-constrained tuner PCB layouts.

Technical Context

The TDA7478 implements a cascaded anti-aliasing + 8th-order switched-capacitor bandpass filter centered at 57 kHz (±0.4 kHz tolerance), achieving 22 dB attenuation at ±4 kHz offset and >60 dB rejection at 38 kHz. Its purely digital demodulation path recovers RDDA and RDCL signals without external analog components.

Internal PLL synchronization ensures RDCL clock edges align with incoming RDS data transitions; data remains valid for 416.7 μs after each clock edge-supporting both rising- and falling-edge sampling in downstream decoders. Oscillator control is managed via two dedicated pins: FSEL selects crystal frequency (4.332/8.664 MHz), while OSEL enables internal oscillator or external drive mode.

Key Specifications

Pinout & Package

Package: TSSOP16 (3.0 × 4.4 mm, 0.65 mm pitch), RoHS-compliant ECOPACK® grade, rated for -40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si4702-C10-GM and BA14747F, the E-TDA7478ADTR uniquely delivers full RDS demodulation with zero external passive components while retaining direct MPX analog input compatibility - making it optimal for incremental RDS upgrades and cost-sensitive tuner modules.

Availability

E-TDA7478ADTR is available at Aetrix Electronics and suitable for automotive FM tuner modules, consumer digital radio receivers, and aftermarket car stereo systems requiring stable component supply and long-lifecycle availability.

Supply support for E-TDA7478ADTR 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, MEMS, and power management devices for industrial, automotive, and consumer markets.

The TDA7478 belongs to ST's audio signal processing product line, engineered specifically for high-fidelity RDS demodulation in cost-sensitive FM radio systems where analog integration, low EMI, and EBU compliance are mandatory design requirements.

FAQ

What crystal specifications are required for E-TDA7478ADTR?

The E-TDA7478ADTR supports two crystal frequencies: 4.332 MHz (standard) and 8.664 MHz (optional). For 4.332 MHz operation, ST recommends 27 pF load capacitance; for 8.664 MHz, 47 pF is suggested. Crystals must meet ±100 ppm frequency tolerance and operate within -40°C to +85°C ambient range. No external capacitors are needed due to internal oscillator tuning.

How does the QUAL pin indicate RDS lock status?

The QUAL pin outputs a logic-high signal when the internal PLL achieves stable lock and the RDS signal-to-noise ratio exceeds the detection threshold (typically ≥30 dB). It remains low during acquisition, weak-signal conditions, or loss of MPX input. The output is open-drain and requires an external pull-up resistor (typically 10 kΩ to VS) for proper logic-level translation to MCU GPIO inputs.

Can E-TDA7478ADTR be used with external clock sources?

Yes - connecting OSEL to GND disables the internal oscillator and enables external clock injection on OSCIN. The device accepts sinusoidal inputs from 4.332 MHz or 8.664 MHz sources with peak-to-peak amplitudes as low as 60 mV. This mode reduces electromagnetic emissions and allows synchronization to system-wide clock domains in multi-IC tuner architectures.

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

The FILOUT pin provides access to the 57 kHz bandpass-filtered signal before demodulation. Engineers use it for oscilloscope verification of filter center frequency and bandwidth during production test or field diagnostics. It also enables optional analog post-processing stages, such as envelope detection for RSSI estimation or spectral analysis in broadcast monitoring equipment.