No. 5128-5/8

LC78856M, 78856V

Pin Functions

SSOP

MFP

Symbol

Function

1

1

RSTB

Reset input (A low-level input resets the LSI internal circuits.)

2

2

CNT1

Emphasis on/off switching input

3

3

CNT2

Standard speed/double speed switching input

4

4

CNT3

Soft mute input

5

5

BCLK

Bit clock input

6

6

LRCK

LR clock input

7

7

DATA

Digital audio data input

10

8

MODE

Input format setting

11

9

CKO

Clock output

12

10

Oscillator amplifier power supply

13

11

XIN

Oscillator amplifier input

14

12

XOUT

Oscillator amplifier output

15

13

XGND

Oscillator amplifier ground

16

14

DGND

Digital system ground

17

15

MRO

Right channel mute signal output

18

16

TEST

Test pin (Must be tied low in normal operation.)

19

17

Analog system power supply

20

18

OUTRA

Right channel output A

21

19

AGND2

Analog system ground

22

20

OUTRB

Right channel output B

23

21

Analog system power supply

24

22

Analog system power supply

25

23

OUTLB

Left channel output B

26

24

AGND1

Analog system ground

27

25

OUTLA

Left channel output A

28

26

Analog system power supply

29

27

MLO

Left channel mute signal output

30

28

Digital system power supply

Operating Description

The LC78856M and LC78856V internal circuits can be roughly divided into the digital filter block and the 1-bit D/A

converter block.

[Digital Filter Block]

1. Standard Speed

The LC78856M and LC78856V implements 8

× oversampling using three FIR filters: a 43rd-order filter, an 11th-

order filter, and a 3rd-order filter. A 1st-order IIR filter is used for de-emphasis.

2. Double Speed

Double-speed playback is used, for example, for dubbing CDs to audio tape at double speed. Here, the same

frequency is used for XIN, but BCLK, LRCK and DATA are input at twice the rates used in standard-speed

playback. After de-emphasis is applied with a 1st-order IIR filter, the signal is 4

× oversampled using a 43rd-order

FIR filter and a 3rd-order FIR filter.