Rohm BA1451F Quick start guide

BA1451F
Audio ICs
AM radio / FM IF stereo system IC
BA1451F
The BA1451F is a tuner system IC for electronic tuning for AM radios, FM IF, and MPX. It has been developed for HiFi
component applications.
The MPX VCO circuit requires no adjustment, which will enable a reduction in the number of production line processes.
In particular, the laser lock technique used in the VCO means that no external adjustment is required.
!Applications
Synthesized tuner for HiFi components.
!Features
1) Built-in AM monaural radio, FM IF amplifier/detector, and FM stereo demodulator.
2) DTS (both SD and IF count) compatible.
3) Built-in reference voltage power supply provides good shortwave band frequency stability.
4) Good FM stability.
5) The FM MPX VCO uses laser locking making adjustment and external components unnecessary.
6) Built-in forced monaural operation function for MPX (VCO stops, and LED goes off).
7) Low cutoff of audio is possible to improve AM fidelity.
8) MPX VCO stops in AM mode.
9) Audio muting is possible when an IF request is made.
!
!!
!Block diagram
24 23 22 21 20 19 18 17 16 15 14 13
123456789101112
Vreg
AM
OSC AM
MIX
AM
DET AGC
SD
PD
SW
DECODER
LED
DRIVER
FM
DET
SD
DET GNDVcc
FM
IF
VCO
COMP
1/2
1/2
AM IF

BA1451F
Audio ICs
!
!!
!Absolute maximum ratings
Parameter Symbol Limits Unit
V
CC
9.0 V
Pd 450∗
1
mW
Topr −25∼+75 ˚C
Tstg −55∼+125 ˚C
Power supply voltage
Power dissipation
Operating temperature
Storage temperature
∗
1 Reduced by 4.5mW for each increase in Ta of 1 ˚ C over 25 ˚ C.
!
!!
!Recommended operating conditions (Ta=25°C)
Parameter Symbol Min. Typ. Max. Unit
3.8 5.0 8.0 VV
CC
Power supply voltage
!
!!
!Input and output circuits
FM AM
1 2.1 2.1
2 5.0 5.0
3 0.25 0
400
5 5.0
6−−
7−−
2
23
1
4
V
CC
V
reg
GND
330Ω
23
4
V
CC
GND
15kΩ
2
4
V
CC
GND
5
5pF
5.0
Pin No.
Function Internal circuit Quiescent voltage (V)
FM IF amplifier input
Connect to an FM ceramic filter.
V
CC
FM tuning ON level adjustment
Connect a resistor from this pin to GND
to set the required ON level for
the tuning indicator.
GND
FM discriminator
Connect to the discriminator coil.
Tuning indicator
Connect to a tuning indicator
display device (eg. LED)
Stereo indicator
Connect to a stereo indicator
display device (eg. LED)
6/7
4GND

BA1451F
Audio ICs
FM AM
800
9 4.2 4.2
10 1.5 1.5
11 1.5 1.5
12 0
13
GND
10kΩ
10k Ω
MUTE
IF OUT
8
4
2
4
9
V
CC
GND
V
CC
GND
5kΩ
10/11
2
4
23
4
12
AM/FM
82kΩ
GND
23
4
GND
4kΩ
13
2.1
V
reg
V
reg
MONO
2.1 2.1
Pin No.
Function Internal circuit
Quiescent pin voltage (V)
·IF request
Output the IF signal to pin9 excess
of 4.0V.
Stops the IF signal at equal to or less
than 3.0V.
·MUTE
Apply to muting excess of 2.0V.
Off the muting at equal to or less
than 1.0V.
IF output
Output for the IF signal.
R-channel output
L-channel output
·PLL filter
Connect to a lag/lead filter.
·AM / FM band switch
AM band when connected to GND.
·Forced monaural
Forced monaural operation connecting
to get a resistor to mediate.
(Recommended value : 10kΩto
ground.)
·Pilot filter
Connect to a capacitor.

BA1451F
Audio ICs
FM AM
14
15
16
17 00
18 5.0 5.0
19 5.0 5.0
20 2.1 2.1
2
23
14
4
15
100kΩ
V
CC
V
reg
GND
20kΩ
5kΩ
V
CC
GND
2
4
16
2
4
17
20kΩ
V CC
GND
2
18
4
V CC
GND
2
23
20
4
19
V
CC
V
reg
GND
30kΩ
2.1 2.1
2.12.1
2.1 2.1
3kΩ
Pin No.
Function Internal circuit
Quiescent pin voltage (V)
MPX input
Input the FM detector output .
MPX input
Input the AM detector output after
low cut.
AM/FM detector output
Connect to the following stage MPX and
FM low pass filter.
AM AGC
Connect to a capacitor.
AM IF input
Connect to an AM ceramic filter.
AM mixer output
Connect to primary side of AM IFT.
AM antenna
Connect to AM antenna.

BA1451F
Audio ICs
FM AM
21 2.1 2.1
23 2.1 2.1
22 2.1 2.1
24 1.7 1.4
21
2
4
4.3kΩ
V
CC
GND
22
24
23
4
100Ω
V
reg
GND
Pin No.
Function Internal circuit
Quiescent pin voltage (V)
FM detector bandwidth adjustment
Connect a resistor from this pin to the
reference voltage supply to set the
required detector bandwidth.
Reference voltage supply
Connected to a capacitor.
AM local oscillator
Connect to the AM OSC circuit.
AM local oscillator output
AM OSC output.
!
!!
!Electrical characteristics (Unless otherwise specified, Ta=25°C and VCC=5V)
FM IF MPX signal source : fiN=10.7MHz, modulation 1kHz, 75kHzdev (100%)
19kHz7.5kHzdev(10%)
AM : fiN=1000kHz, modulation 1kHz 30%
Parameter Symbol Min. Typ. Max. Unit Conditions
I
Q (FM)
29 mA
I
Q (AM)
11 19 mA
V
O
mVrms V
IN
=100dBµV,mono
L.S 40 dBµV mono
S / N −dB V
IN
=100dBµV, mono
C.B −20+2dBV
IN
=100dBµV, mono
AMR −dB
AM : VIN = 60dBµV, mod = 30% , 400Hz
SEP 35 45 −dB V
IN
=100dBµV, main
THD −%V
IN
=100dBµV, main
SD
S
dBµV
SD
SW
100 V
IN
=100dBµV, mono
V
IF
300 400 530
V
O
90 120 mVrms V
IN
=68dBµV
Q.S dBµV
S / N 42 52 −dB V
IN
=68dBµV
THD −0.6 1.8 % V
IN
=68dBµV
SD
S
dBµV
V
IF
300 400 530
V
OBuff
140 200 280 mVrms
mV
P-P
mV P-P
kHz
13 21
340 480 670
27
34 37
72 80
45 55
0.5 1.6
34 39 44
70 150
70
22 25 28
21 26 31
Quiescent current FM
Quiescent current AM
<FM IF MPX>
Detector output voltage
−3dB limiting sensitivity
Signal-to-noise ratio
Channel balance
AM suppression ratio
Channel separation
Total harmonic distortion
Station detector sensitivity
Station detector bandwidth
IF OUT output voltage
<AM>
Detector output voltage
Usable sensitivity
Signal-to-noise ratio
Total harmonic distortion
Station detector sensitivity
IF OUT output voltage
Local buffer output voltage
No input
No input
Input for pin 6 current ≥1mA
IF request ON
Input for S / N = 20dB
Input for pin 6 current ≥1mA
IF request ON

BA1451F
Audio ICs
!
!!
!Test circuit
L4
T2
CD1
2157-JPS-029
CFMA-258
A7BRS-12445X
: AM OSC
: AM IFT
: FM DISCRIMINATOR COIL 0236-JPS-101
A119ACS-19197N
Units : R [Ω]
C [µF]
Sumida
Toko
Toko
Sumida
Toko
Fig. 1
L4
123456789101112
24 23 22 21 20 19 18 17 16 15 14 13
MPX
DET
MUTE
REQ.
LEDDET
MIX
OSC
47p
SG
OSC OUT
AM SG
0.022 0.022
100
Vreg
20k
0.022 50
AM STEREO
T2
22
100p
6800p 1
10
MONO
10k
STEREO
100
Vreg
SD
AM
FM
0.22
0.047
3.3k
L-chR-chIF OUT
ST.TUN.
GNDVcc
24k
0. 022
100
1
50
0.022
FM SG
SG SG
FM STEREO SG
+B
0.022
0.010.01
OFF
MUTE
IFREQ
3.9k

BA1451F
Audio ICs
!
!!
!Application example
Fig. 2
BPF
131415161718192021222324
SDMPXMPXDETAGCIFIN
MIXOUT AM INBW Adj AMVreg
AMFMLchRch IF OUTIF REQ STTUN FM DET GND SD Adj V DD FMIN
5678
4321
101112131415161718
P0P1P2AMINFMINV DD PD1PD2GND
P3IFINSDTUNCLDACEXIN
XOUT
987654321
121110987654321
BA1451F
BU2616F
µ-COM
Vcc2 (+9V)
Vcc (5V)
TUNING
TO LED etc.
Rch OUT
Lch OUT
STEREO
PD
/
MUTE
/
/
MONO
ININOUTAM AMOSC
OSC
OUT
BA4425F
CL
DA
CE
!
!!
!Electrical characteristic curves
Fig.3 FM input / output characteristics
S+D+N
060
− 20 100 120
−90
1
2
3
4
5
6
7
−80
−70
−60
−50
−40
−30
−20
−10
0
L→R
AMR
N
D+N (100%)
D+N (30%)
INPUT VOLTAGE : VIN ( dBµ)
TOTAL HARMONIC DISTORTION : THD (%)
Vo, AMR, SEP (dB)
V cc =5V,
f
IN =10.7MHz,
fm=1kHz
∆f=±22.5kHzdev,
pilot=±7.5kHzdev
Ta=25˚C,
AMR MOD=30%,
fm=400Hz
SEP
R→L
020 40 80
f IN =10.7MHz,
V
IN =100dBµ,
∆f=±22.5kHzdev.
(pilot=±7.5kHzdev)
f
IN =1kHz,
Ta=25˚C,
RSD=20kΩ
POWER SUPPLY VOLTAGE : V CC (V)
3456789
0
1
2
3
4
5
6
7
8
9
10
11
0
10
20
30
40
50
60
70
80
90
100
110
−3dBL, S, TUNED ON (dBµ) SEP (dB)
TOTAL HARMONIC DISTORTION : THD (%)
V O
R→L
L→R
70
80
90
100
110
120
130
140
150
160
170
180
Vo (mVrms)
Fig.4 FM characteristics vs.
power suppy voltage
TUNED ON
−3dB L.S.
D+N (100%)
D+N (30%)

BA1451F
Audio ICs
3456789
10.80
10.75
10.70
10.65
10.60
10.55
POWER SUPPLY VOLTAGE : Vcc (V)
R BW =20kΩ, V IN =100dBµ
Ta=25˚C
FM BAND WIDTH : f
IN
(MHz)
Fig.5 FM bandwidth vs.
power supply voltage
TOTAL HARMONIC DISTORTION : THD (%)
CHANNEL SEPARATION : SEP (dB)
50
40
30
20
1
10
0
2
0
FREQUENCY : fm (Hz)
50 100 200 500 1k 2k 5k 10k 20k
SEP
THD
Vcc=5V
f
IN =10.7MHz
V
IN =100dBµ
∆f=±22.5kHzdev
pilot=±7.5kHzdev
Ta=25˚C
L→R
R→L
60
MAIN R
L
SUB
MONO
Fig.6 Channel separation and
THD vs. frequency
Fig.7 AM input / output characteristics
10
0
−10
−20
−30
−40
−50
−60
−70
−20 050 100 120
TOTAL HARMONIC DISTORTION : THD (%)
OUTPUT VOLTAGE : V
O
(dB)
INPUT VOLTAGE : V IN (dBµ)
V OUT =5V,
f
IN =1000kHz,
f
m =1kHz
MOD=30%,
Ta=25˚C
S+D+N
V
AGC
N
D+N (80%)
D+N (30%)
0
1
2
3
4
5
6
7
8
9
10
S / N=20dB
0
1.0
2.0
3.0
LED ON
V
AGC
(V)
f IN =1000kHz,
V
IN =74dBµ,
MOD=30%
f
m =1kHz,
Ta=25˚C
TOTAL HARMONIC DISTORTION : THD (%)
Q.S. , TUNED ON : (dBµ)
OUTPUT VOLTAGE : Vo (mVrms)
POWER SUPPLY VOLTAGE : V CC (V)
100
90
80
70
60
50
40
30
20
10
0
10
9
8
7
6
5
4
3
2
1
034 56789
Vo
TUNED ON
Q.S.
100
90
80
70
60
50
40
30
20
10
0
Fig.8 AM characteristics vs.
power suppy voltage
D+N (80%)
D+N (30%)
!
!!
!External dimensions (Units : mm)
Fig.9 AM detector output and
THD vs. frequency
FREQUENCY : fm (Hz)
TOTAL HARMONIC DISTORTION : THD (%)
AM DETECTOR OUTPUT VOLTAGE : V
O
(dBm)
10
0
−20
−40
−50
−60
−70
−10
−30
50 100 200 500 1k 2k 5k 10k 20k
V O
D+N (80%)
D+N (30%)
VCC = 5V
fIN
= 1000MHz
VIN
= 74dBµ
MOD
= 30%
Ta
= 25˚C
0
5
10
SOP24
0.15
0.11
1.8 ± 0.1
5.4 ± 0.2
7.8 ± 0.3
0.4 ± 0.1
15.0 ± 0.2
0.3Min.
0.15 ± 0.1
24
1
13
12
1.27