ROHM BA1451F Datasheet

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

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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

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24 23 22 21 20 19 18 17 16 15 14 13

LED

DRIVER

AM IF

AM

DET

AGC

COMP

DECODER

SD

SW

PD

VCO

AM

OSC

Vreg

FM

IF

123456789101112

SD

DET

GNDVcc

AM

MIX

FM

DET

1/2

1/2

Audio ICs

Absolute maximum ratings

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Parameter Symbol Limits Unit

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

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Parameter Symbol Min. Typ. Max. Unit

Power supply voltage

Input and output circuits

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Pin No.

Function

V

CC

Pd 450
Topr −25∼+75 ˚C
Tstg −55∼+125 ˚C

(Ta=25°C)

CC

3.8 5.0 8.0 VV

9.0 V

1

∗

mW

Internal circuit

2

V

CC

V

23

reg

BA1451F

Quiescent voltage (V)

FM AM

FM IF amplifier input

1 2.1 2.1

Connect to an FM ceramic filter.

V

CC

2 5.0 5.0

1

4

GND

2

V

CC

330Ω

3

FM tuning ON level adjustment

3 0.25 0

Connect a resistor from this pin to GND
to set the required ON level for
the tuning indicator.

4

GND

GND

4 00

24V

CC

FM discriminator

5 5.0

Connect to the discriminator coil.

GND

5

5pF

Tuning indicator

6 −−

Connect to a tuning indicator

15kΩ

5.0

6/7

display device (eg. LED)
Stereo indicator

Connect to a stereo indicator

7 −−

display device (eg. LED)

4GND

Audio ICs

BA1451F

Pin No.

· IF request
Output the IF signal to pin9 excess
of 4.0V.
Stops the IF signal at equal to or less
than 3.0V.

8 00

Function Internal circuit

10k

MUTE

Ω

10kΩ

8

IF OUT

Quiescent pin voltage (V)

FM AM

· MUTE
Apply to muting excess of 2.0V.
Off the muting at equal to or less
than 1.0V.

IF output

9 4.2 4.2

Output for the IF signal.

10 1.5 1.5

R-channel output

11 1.5 1.5

L-channel output

GND

V

GND

V

GND

CC

4

2

CC

9

4

2

10/11

5kΩ

4

23

V

· PLL filter

reg

Connect to a lag/lead filter.

12 0

12

82kΩ

AM/FM

2.1

· AM / FM band switch
AM band when connected to GND.

4

GND

· Forced monaural
Forced monaural operation connecting
to get a resistor to mediate.
(Recommended value : 10kΩ to

13

ground.)

23

V

reg

13

4kΩ

MONO

2.1 2.1

· Pilot filter

GND

Connect to a capacitor.

4