The TDA7478 is a single-chip RDS demodulator from STMicroelectronics. It recovers the additional inaudible RDS information transmitted by FM radio broadcasting stations and operates in accordance with EBU specifications. The device combines an antialiasing and switched-capacitor 8th-order bandpass filter with a demodulating section that extracts the RDS data stream and clock for further processing by an RDS decoder.
The datasheet describes the block diagram and pin connections, electrical specifications including thermal data and absolute maximum ratings, output timing, and oscillator control through the FSEL and OSEL pins. It also lists package information and revision history.
| Absolute maximum supply voltage | -0.3 to 7 V |
|---|---|
| Operating temperature range | -40 to 85 °C |
| Storage temperature | -55 to 150 °C |
| Thermal resistance junction-to-case | Max. 200 °C/W |
| Filter center frequency | 57 kHz (min 56.6 kHz, max 57.4 kHz) |
| Gain at 57 kHz | 17 to 23 dB (typ. 20 dB) |
| Supply current | 7.5 mA typ., 12.0 mA max |
| RDS detection sensitivity | 1 mVrms |
| Crystal oscillator | 4.332 MHz (8.664 MHz optional) |
It recovers the additional inaudible RDS information transmitted by FM radio broadcasting stations and outputs an RDS data stream and clock for an RDS decoder.
It supports 4.332 MHz and 8.664 MHz crystals; the FSEL pin selects the frequency.
The QUAL pin outputs signal quality indication; high means good.
RDCL is the RDS clock output at 1187.5 Hz.