ROHM BH3856S, BH3856FS Datasheet

Audio ICs

2-wire serial sound control IC

BH3856S / BH3856FS

The BH3856S and BH3856FS are signal processing ICs designed for volume and tone control in televisions, mini component stereo systems, and other audio products. Their two-line serial control (I

2

C BUS) enables them to control

volume and tone on the basis of signals from a microcomputer, etc.

Applications

!!!!

Televisions, [Video equipped television], personal computer televisions, mini component stereo systems, car stereos.

Features

!!!!

2

1) I

C BUS facilitates direct serial control from a microcomputer of volume (main volume), balance (left / right), and tone

(bass, treble). DC control is also possible.

2) Volume is produced by a low-distortion, low-noise VCA. Designed to minimize step noise.

3) Stable standard voltage supply and built-in I/O buffer mean that few attachments are needed. SSOP-A32 package designed to save space.

4) Matrix surround yields powerful sound.

Absolute maximum ratings

!!!!

Parameter Symbol Limits Unit

Power supply voltage 10.0 V

Power dissipation Operating temperature

Storage temperature

1 Reduced by 12mW for each increase in Ta of

∗

2 Reduced by 6.8mW for each increase in

∗

(Ta = 25°C)

BH3856S BH3856FS

Ta of 1°C over 25°C.

Vcc

Pd

Topr Tstg

1°C over 25°C.

1200

850

−40~+85

−55~+150

1

∗

2

∗

mW

°C °C

Recommended operating conditions

!!!!

Parameter Symbol Min. Typ. Max. Unit

Power supply voltage 6.0 9 9.5 VV

Note : I2C BUS is a registered trademark of Philips.

CC

(Ta = 25°C)

Audio ICs

Block diagram

!!!!

BH3856S / BH3856FS

BH3856S

1

A_GND

2

IN1

3

BVN1

BIN1

4

5

BVO1

6

TVN1

7

TIN1

8

TVO1

9

OUT1

10

V

CC

11

SC

12

N.C.

13

SDA

14

SCL

D_GND

15

BH3856FS

1

A_GND

2

IN1

3

BVN1

4

BIN1

5

N.C.

6

BVO1

7

TVN1

TIN1

8

TVO1

9

10

OUT1

11

CC

V

12

SC

13

SDA

14

N.C.

15

SCL

D_GND

16

30k 30k

47k

+

−

(Bass) (Treble)

5.1k

Tone

Volume

Matrix surround

2.1k 2.1k

−

+

Volume Volume

V

CC

200k

Reference Voltage

30k 30k

47k

+

−−

Tone

Volume

Matrix surround

−

+

Volume

Reference Voltage

5.1k

2.1k

V

200k

(Bass)

(Treble)

CC

−−

Control

−−

Control

47k

+

Volume

+

Volume

V

CC

(Bass) (Treble)

−

Tone

−

+

V

CC

(Bass)

Tone

(Treble)

−

+

5.1k

30k 30k

30k

5.1k

2.1k

30k 30k

30k

30

FILTER

29

IN2

28

BVN2 BIN2

27

BVO2

26

25

TVN2

TIN2

24

TVO2

23

OUT2

22

21

VC1

VC2

20

19

TC

18

BC

17

V

ref

SLAVE ADDRESS

16

SELECT SW

32

FILTER

31

IN2

30

BVN2

29

N.C. BIN2

28

27

BVO2

26

TVN2

25

TIN2

24

TVO2

23

OUT2

22

VC1

VC2

21

TC

20

BC

19

18

V

ref

SLAVE ADDRESS

17

SELECT SW

Audio ICs

Pin descriptions

!!!!

Pin No.

BH3856S BH3856FS

1 2 3 4 5 6 7 8

9 10 11 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 12

1 A_GND 2 IN1 3 BVN1 4 BIN1 6 7

9

11 12 13 15 16 17 18 19 20 21 22 23 24 25 26 27 28 30 31 32

5, 14, 29

Pin name

BVO1 TVN1

TIN1 Channel 1 treble filter8

TVO1 OUT110

V

CC

SC

SDA

SCL

D_GND

SASS

V

ref

BC

TC VC2 VC1

OUT2 TVO2

TIN2 TVN2 BVO2

BIN2 BVN2

IN2

FILTER

N.C.

BH3856S / BH3856FS

Function

Analog ground Channel 1 volume input Channel 1 bass filter Channel 1 bass filter Channel 1 bass filter Channel 1 treble filter

Channel 1 treble filter Channel 1 volume output Power supply Time constant pin for prevention of switching shock SDA data input pin SCL data input pin Digital ground

Slave address selection pin Reference voltage output Time constant pin for prevention of switching shock Time constant pin for prevention of switching shock Time constant pin for prevention of switching shock Time constant pin for prevention of switching shock Channel 2 volume output Channel 2 treble filter Channel 2 treble filter Channel 2 treble filter Channel 2 bass filter Channel 2 bass filter Channel 2 bass filter Channel 2 volulme input Filter Not connected internally.

Audio ICs

Input / output circuits

!!!!

Symbol

Pin voltage

Equivalent circuit

V

CC

BH3856S / BH3856FS

Description

IN1 IN2

BVN1 BVN2

BIN1 BIN2

BVO1 BVO1

4.5V

FILTER 5.2V

2pin 31pin

A_GND

V

A_GND

V

4pin 28pin

A_GND

V

6pin 27pin

A_GND

V

A_GND

CC

V

Main volume input pin.

47kΩ

2/1V

CC

50kΩ

3pin 30pin

CC

5.1kΩ

2/1V

CC

50kΩ

CC

30kΩ

Designed for input impedance of 47kΩTyp.).

Pin for low band filter connection.

Filter input pin. Please install a capacitor of about 10µF to the filter pin.

32pin

30kΩ

Has built-in precharge and discharge circuits.

TVN1 TVN2

TIN1 TIN2

4.5V

A_GND

CC

V

8pin 25pin

A_GND

25kΩ

7pin 26pin

2.1kΩ

CC

2/1V

Pin for high band filter connection.

∗

The pin numbers are for the BH3856S.

BH3856S / BH3856FS

Audio ICs

Symbol Pin voltage Equivalent Circuit Description

CC

V

TVO1 TVO2

OUT1 OUT2

SC BC

TC VC1 VC2

V

ref

4.5V

−

3.8V

A_GND

V

10pin 24pin

A_GND

CC

V

12pin 19pin 20pin 22pin 21pin

A_GND

CC

V

18pin

A_GND

CC

V

25kΩ

9pin 24pin

CC

Pin for high band filter connection.

Main volume output pin. OUT1 is the volume output for Channel 1. OUT2 is the volume output for Channel 2.

Digital

VREF

For prevention of shock noise during step switching. SC : Surround pin BC : Bass pin TC : Treble pin VC1 : Volume pin (Channel 1) VC2 : Volume pin (Channel 2)

3.8V regulator output pin. Output requires capacitor for stopping oscillation. Output pin has built-in precharge and discharge circuits, so there is no problem with start-up or shut-down even with a large capacitor. This pin is for connection to the high-band filter.

SDA SCL

SASS

V

CC

A_GND D_GND

−

Power supply voltage pin.

−

Analog GND pin. Connected to IC board.

Digital GND pin. Separate from Analog GND pin.

−

13pin 15pin 17pin

A_GND

2kΩ

· I2C bass input pin SDA : serial data line SCL : serial clock line

· Slave address selection pin SASS: slave address selection switch

∗

The pin numbers are for the BH3856S.