18

Multimedia ICs

BA7786FP-Y / BA7787FS

No.

Use

Standard value

R1

Used to set the gain from LINE IN L / LINE IN R (pins 2 and 4) to HP OUT

L / HP OUT R (pins 19 and 18) (See section 1, on circuit operation for the formula.)

27k

Ω

R2

27k

Ω

R3

A wide range of mixing ratios can be set by changing the values of R1, R2 and

R3 (or R4, R5 and R6).

27k

Ω

R4

27k

Ω

R5

27k

Ω

R6

27k

Ω

R7

33k

Ω

R8

33k

Ω

R9

33k

Ω

R10

• Used to set the gain from SP IN (pin 7) to SP OUT 1 / SP OUT 2

(pins 14 and 13). (See section 3, on circuit operation for the formula.)

• Used to set the output level from SYSTEM BEEP IN (pin 6) to HP OUT

L / HP OUT R (pins 19 and 18). (See section 2, on circuit operation for the formula.)

15k

Ω

15k

Ω

18k

Ω

390k

Ω

R12

R11

R13

• Used to set the gain from PM BEEP IN (pin 8) to SP OUT 1 / SP OUT 2

(pins 14 and 13).

R14

• The load resistor for HP OUT R.

100

Ω

• The load resistor for HP OUT L.

100

Ω

R15

20k

Ω

C1

• The coupling capacitor for LINE IN L

0.1

µF

C2

• The coupling capacitor for LINE IN R

0.1

µF

C3

• The ripple rejection capacitor for the bias pin

47

µF

C4

• The coupling capacitor for SYSTEM BEEP IN

0.1

µF

C5

0.1

µF

C6

• The coupling capacitor for PM BEEP IN

• The coupling capacitor for SP IN

0.1

µF

C7

100

µF

C8

0.1

µF

0.1

µF

C9

• The coupling capacitor for HP OUT R

47

µF

C10

• The coupling capacitor for HP OUT L

47

µF

C11

C12

VR1

• Used to change the pin 1 DC voltage

100

µF

BA7787FS

(See section 4, on circuit operation for the formula.)

Resistors for mixing SYSTEM BEEP IN (pin 6). Because the threshold voltage

between the high and low levels is fixed inside the IC, these resistors should be set

to 33k

Ω.