Rohm BU1920 Rds / rbds decoder Datasheet

Audio ICs
RDS / RBDS decoder
BU1920 / BU1920F / BU1920FS
The BU1920, BU1920F and BU1920FS are RDS / RBDS decoders that employ a digital PLL. It has a built-in anti-aliasing filter and an eight-stage BPF (switched-capacitor filter). Linear CMOS circuitry is used for low current dissipation.
Applications
RDS / RBDS compatible FM receivers for Europe and North America, car stereo systems, home stereo systems and FM
pagers.
Features
1) Low current dissipation.
2) Two-stage anti-aliasing filter.
3) 57kHz bandpass filter.
Absolute maximum ratings (Ta = 25C)
Recommended operating conditions (Ta = 25C)
170
4) DSB demodulation (digital PLL).
5) ARI signal discrimination.
6) Quality indication output for demodulated data.
Audio ICs
BU1920 / BU1920F / BU1920FS
Block diagram
Application example
Pin assignments
171
Audio ICs
Pin descriptions
172
BU1920 / BU1920F / BU1920FS
Audio ICs
BU1920 / BU1920F / BU1920FS
Input / output circuits
173
Audio ICs
BU1920 / BU1920F / BU1920FS
Electrical characteristics (unless otherwise noted, Ta = 25C, VDD = 5.0V and GND = 0.0V)
Filter block
Demodulator block
174
Audio ICs
BU1920 / BU1920F / BU1920FS
Output data timing
The clock (RCLK) frequency is 1187.5Hz. Depending on
the state of the internal PLL clock, the data (RDATA) is
replaced in synchronous with either the rising or falling
edge of the clock. To read the data, you may
choose either the rising or falling edge of the clock as the
reference. The data is valid for 416.7µs, after the reference clock edge.
QUAL pin operation: Indicates the quality of the demodulated data.
(1) Good data
: HI
(2) Poor data
: LO
ARI pin operation: ARI / RDS discrimination.
(1) ARI
: LO
(2) RDS + ARI
: LO
(3) RDS
: HI
(4) No signal
: unstable
Electrical characteristics curve
175
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