RDS (RADIO DATA SYSTEM) DEMODULATOR IC
S1A0905X01
1
INTRODUCTION
Recovers the RDS data which is transmitted by FM radio broadcasting.
(European Broadcasting Union) specifications.
The IC includes
two stage antialiasing filter
57kHz switched capacitor bandpass filter
comparator
57kHz carr ier recovery circuit
bit rate clock recovery circuit
BPSK decoder
differential decoding circuit
RDS signal quality output
ORDERING INFORMATION
DEVICE
PACKAGE
OPERATING TEMPERATURE
S1A0905X01
16-SOP-225
-20
+85
C
FEATURES
Low Current
Two Stage Anti- Aliasing Filter
8'th 57kHz Switched Capacitor Bandpass Filter
DSB Demodulation(Carrier Recovery)
Clock Recovery Circuit
Biphase Decoder & Differential Decoder
Quality Indication Output for Demodulated Data
#1
SEC
S1A0905X01
16 SOP
(TOP VIEW)
#8
#16
#9
S1A0905X01
RDS (RADIO DATA SYSTEM) DEMODULATOR IC
2
BLOCK DIAGRAM
VREF
VDDA
QUAL
DATAO
CLKO
RSTB
TIN
VSS
SCBPF8
Smoothing filter
&
Comparator
MUX
VSSA
SGND
COMP
TEST
VDD
XOSCI
XOSCO
SCBPF2D
SCBPF2C
SCBPF2B
SCBPF2A
1
16
2
3
4
5
6
7
8
9
10
11
12
13
14
15
XOSC & DIVIDER
DCLK
GENERATOR
QUAL
GEN
DIFFERENTIAL
GENERATOR
BPSK NOISE
REJECTOR
BPSK
GENERATOR
DATA
GENERATOR
BGR/BIAS
LPF1
RDS (RADIO DATA SYSTEM) DEMODULATOR IC
S1A0905X01
3
PIN DESCRIPTION
QUAL
DATAO
VREF
MUX
VDDA
VSSA
SGND
COMP
SEC
S1A0905X01
TEST
TIN
VSS
VDD
XOSCI
XOSCO
RSTB
CLKO
16 SOP
(TOP VIEW)
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
S1A0905X01
RDS (RADIO DATA SYSTEM) DEMODULATOR IC
4
PIN DESCRIPTION
PIN NO.
SYMBOL
IN/OUT
FUNCTION
1
QUAL
O
Output for signal quality indication.
(High = good ,Low = bad data)
2
DATAO
O
RDS data output (1187.5bps)
3
VREF
O
Reference voltage output (1/2*VDDA)
4
MUX
I
RDS signal input (DSB-SC)
5
VDDA
P
Analog power supply (5.0V)
6
VSSA
P
7
SGND
P
Signal ground
8
COMP
O
Positive comparator input
9
TEST
I
Control pin for test mode.(Normal = GND)
10
TIN
I
Input for test mode.(Normal = GND)
11
VSS
P
Digital power supply (5.0V)
12
VDD
P
13
XOSCI
I
Crystal oscillator Input
14
XOSCO
O
Crystal oscillator output
15
RSTB
I
Input for system reset
16
CLKO
O
RDS clock output (1.1875kHz)
RDS (RADIO DATA SYSTEM) DEMODULATOR IC
S1A0905X01
5
ELECTRICAL CHARACTERISTICS
Recommended Operating Conditions (Ta = 25
C)
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
Analog Power Supply
VDDA
4.5
-
5.5
V
Digital Power Supply
VDD
4.5
-
5.5
V
Operating Temperature
T
OP
-20
85
C
Storage Temperature
T
STG
-40
150
C
Electrical Characteristics(VDDA,VDD = 5.0V,Tamp = 25
C, unless otherwise specified)
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
Operating Current
I
SUM
-
4.0
7.0
mA
I
VDDA
+ I
VDD
Reference Voltage
VREF
2.3
2.5
2.7
V
MPX input (Signal before the capacitor pin 4)
RDS Amplitude
V
RDS
-
-
1.0
mVrms
f =
2kHz RDS
Maximum Input Capability
V
MAX
0.2
-
-
Vpp
Input Impedance
Ri
40
-
-
k
f = 0 to 100kHz
Filter block
Center Frequency
Fc
56.5
57.0
57.5
kHz
Gain
A
V
23
26
29
dB
Fc = 57kHz
ATT1
31
-
-
dB
F =
7kHz
ATT2
Attenuation
ATT3
40
-
-
dB
F < 45kHz
ATT4
60
-
-
dB
F < 20kHz
ATT5
40
-
-
dB
F > 70kHz
Signal to Noise Ratio
SN
30
40
-
dB
57kHz
Vin=3mVrms
Demodulator block
High Level Output
V
OH
4.0
-
-
V
Low level Output
V
OL
-
-
0.4
V
Clock Rate
C
RATE
-
1187.5
-
Hz
Oscillator block
Oscillation Frequency
F
OSC
-
4.332
-
MHz
Clock Input High Level
X
OSCI
4.0
-
-
V
Clock Input Low Level
X
OSCO
-
-
1.0
V
Output Amplitude
X
OSC
-
4.5
-
Vpp
Load Capacitance
CL
-
47
-
pF
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