TA8155FN Просмотр технического описания (PDF) - Toshiba

Номер в каталоге

Компоненты Описание

Список матч

TA8155FN

TOSHIBA Bipolar Linear Integrated Circuit Silicon Monolithic

Toshiba 

TA8155F / FN

Application Note

(1) PW SW

It is necessary to connect an external pull-down resistor with the terminal PW SW (pin(12)), in case that this IC

is turned on due to external noise etc.

(2) Mode SW

Table.1 IC mode

IC mode is determined by switch condition

of RED SW (pin(11)) and LINE SW (pin(15))

(Table.1)

H level: Bias current should be applied

to switch terminal more than 5µA.

L level: Bias voltage should be applied to

switch terminal from 0V to 0.3V.

LINE SW

REC SW

L

L

PB mode

(PB)

H

Radio mode

(BUF)

( ) : Operating amplifier.

H

MIC-REC

(BUF,MIC,REC)

Radio-REC mode

(BUF,REC)

The leak current flows through the terminal of REC SW (pin(11)) or LINE SW (pin(15)), in case that the

terminals connected with VCC line independently, even though this IC is off-mode (the terminal of PW SW

(pin(12)) is off-mode).

And it is necessary to connect an external pull-down resistor with the terminal REC SW (pin(11)) and LINE SW

(pin(15)), in case that this IC is turned on due to external noise etc.

(3) Playback amplifier

Output voltage of playback amplifier is determined by an external resistor R1 and Rf.

VO

(PRE)

=

VREF-∆V-Rf

(

DV

R1

- IB(NF) )

∆V is an off-set voltage which is designed to 18mV.

In case that β of transistor is assumed 100, IB(NF) is flowed 0.2µA in Fig.1. And output voltage of playback

amplifier (pin (8),(9)) in Fig.1 is

VO (PRE) = 0.85V-0.018V- (330kΩ+13kΩ)

x

(

0.018V

18kW

-

0.2mA )

=

0.56(V)

Output voltage of playback amplifier should be fixed VCC / 2,

because playback amplifier get a enough dynamic range.

And current source of 20µA is operated except playback

mode, in order to reduce a pop sound in

swichover between playback on / off mode (Fig.2).

Fig.1 DC output voltage of

playback amplifier.

5

2002-10-30

Share Link: