HA12177 データシートの表示（PDF） - Hitachi -> Renesas Electronics

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HA12177

Audio Signal Processor for Car Deck and Cassette Deck (Dolby B/C-type NR with PB Amp)

Hitachi -> Renesas Electronics 

HA12173 Series

Input Block Diagram and Level Diagram

R34

5.1 k

R35

5.1 k

R38

330 k

R39

180

R36

12 k

R37

18 k

C25

0.01 µ

C24

0.1 µ

EQ OUT

TAI

30 mVrms

EQ OUT-M (–28.2 dBs)

HA12173: 300 mVrms (–8.2 dBs)

HA12174: 450 mVrms (–4.7 dBs)

HA12175: 580 mVrms (–2.5 dBs)

HA12177: 775 mVrms (0.0 dBs)

RAI

42.4 mVrms

(–25.2 dBs)

PBOUT

EQ AMP

–+

NFI

RIN

VREF

0.6 mVrms

(–62.2 dBs)

INPUT AMP

+

–

NR circuit

RECOUT

300 mVrms

(–8.2 dBs)

FIN

Unit R: Ω

C: F

The each level shown above is typical value

when offering PBOUT level to PBOUT pin.

(EQ AMP Gv = 40 dB f = 1 kHz)

Figure 2 Input Block Diagram

Adjustment of Playback Dolby Level

After replace R34 and R35 with a half-fix volume of 10 kΩ, adjust RECOUT level to be Dolby level with

playback mode.

Note on Connecting with Tape Head to IC

This IC has no internal resistor to give the DC bias current to equalizer amp., therefore the DC bias current

will give through the head. This IC provides the Vref buffer output pin for Rch and Lch separately (has

two Vref terminal). In case of use that the Rch and Lch reference of head are connected commonly, please

use one of Vref terminals of IC (47 pin or 52 pin) for head reference. If both 47 pin and 52 pin of IC are

connected, rush current give the great damage to IC. The application circuit is shown in figure 3.

Rev.1, Nov. 1992, page 14 of 66

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