BA7787FS データシートの表示（PDF） - ROHM Semiconductor

部品番号

コンポーネント説明

メーカー

BA7787FS

Headphone / speaker amplifier for notebook computers

ROHM Semiconductor 

Multimedia ICs

BA7786FP-Y / BA7787FS

•Circuit operation

(1) Gain between LINE IN L / LINE IN R and HP OUT L /

HP OUT R

GHP, the gain when EVR is at its maximum (VE = HP

VCC), is calculated as follows:

GHP Լ 20 ∗ LOG 60k (dB)

1k + R

R

2

R

4

R

20

R

21

Gain between SP IN and SP OUT 1 / SP OUT 2

(BA7787FS)

This is calculated as follows.

GSP Լ 20 ∗ LOG 32k (dB)

1k + R

Set so that 12k Ϲ R Ϲ 56k. This gain attenuates accord-

ing to the pin 1 DC voltage (VE) (see Fig. 8). Mixing

input can be accommodated by attaching multiple resis-

tors.

R

7

(4) Gain between PM BEEP IN and SP OUT 1 / SP OUT 2

This is calculated as follows.

(2) Output level between SYSTEM BEEP IN and HP

OUT L / HP OUT R

Inputting a pulse wave to SYSTEM BEEP IN causes HP

OUT L and HP OUT R to output a pulse wave. The out-

put level of this pulse wave depends on the resistance

between pin 7 and GND. The level when EVR is at its

maximum (VE = HP VCC) is calculated as follows.

VHB Լ 0.5 ∗ VCC – 0.7 ∗ 60k (VP-P)

13k + R

GSB Լ 20 ∗ LOG 20k (dB)

1k + R

R

9

(BA7786FP-Y only, BA7787FS: pin 8)

This path is output regardless of whether LIN MIX ON /

OFF is at the high or low level.

R

7

(BA7786FP-Y only, BA7787FS: pin 15)

Set so that R м 100k (VHB Ϲ 1.1V). As with the path be-

tween LINE IN L / LINE IN R and HP OUT L / HP OUT

R, this level attenuates according to the pin 1 DC volt-

age.

(5) Gain between LINE IN L and LCH OUT

(BA7786FP-Y)

This gain (GHL) is calculated as follows.

R8

GHL Լ 20 ∗ LOG

(dB)

2 ∗ R2

R2

2

(3) Gain between SP IN L / SP IN R and SP OUT L / SP

OUT R (BA7786FP-Y)

This is calculated as follows.

GSP Լ 20 ∗ LOG 32k (dB)

1k + R

8

R8

This path is not controlled by EVR or the mute function.

9

Share Link: