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RF, EQ, AGC

The signals A, B, C and D input from PDIC are composed into the RF signal by the RF

Addition Amp, then output from RFOUT of Pin 5. This Amp is designed so that RFOUT is

about 0.5 Vp-p for normal CD disc (about 0.4 Vp-p for CDR and 0.12 Vp-p for CDRW).

RF signal from Pin 5 is then input to the AGC block through the EQ block (the EQ

characteristic is fixed for single speed operation in this design). It is then gain-controlled

and output to Pin 10 ARF. The AGC block maintains the output level of ARF to about

1.0Vp-p for all types of disc. C38 connected to Pin 9 is for the AGC loop filter.

The RF Detection block detects the amplitude of the RF signal inputted from the EQ block.

Inputted RF signal is detected after passing through a high-pass filter. Detection level is

changed in accrodance with the voltage of GCTRL Pin 28.

The ENV detection block detects the fluctuation of the 3T-composition in the RF signal

which is needed for focus balance adjustment. C39 connected to Pin 11 forms a filter for

detecting the signal fluctuation. The ENV output signal from Pin 12 is filtered by C29.

36

34

GCTRL

V

C2

35

33

3

5

C35

C47

R27

R21

R20

6

EQ

AGC

8

9

10

17

RF

DETECTION

ENV

DETECTION

11

12

V

ARF

V

NRFDET

ENV

28

C29

C39

C28

C38

RFOUT

13

APC

The laser diode has large negative temperature characteristic in its optical output when

driven with a constant current on laser diode. Therefore, the output on processing monitor

photo diode, must be a controlled current for getting regular output power, thus the APC

(Auto Power Control) circuit is composed.

Reference Power Supply

A reference power supply for servo is built-in. The current capacity of the reference supply

is about 3 mA.

V

 = 1/2 V

 = 2.5 V

V

 = 1/2 V

 = 1.65 V

where V

 = 5 V and V

 = 3.3 V

19

LD

2

1

V

PD

170mV

LASER UNIT

C33

R18

Q1

LDON

20

R

V

R

R/2

V

22

R

V

R

R/2

V

14

 Overview

The MN662790RSA is a CD signal processing LSI that,

on a single chip, combines optics servos for the CD player
(focus, tracking, and traverse servos), digital signal
processing (EFM demodulation and error correction),
digital servo processing for the spindle motor, digital
filter, and D/A converter, so thus covers all signal
processing functions from the head's RF amplifier onward.

 Features

(Optics servo)

Focus, tracking, and traverse servos
Automatic adjustment functions for FO/TR gain,
FO/TR offset, and FO/TR balance
Built-in D/A converter for drive voltage output
Built-in dropout countermeasures
Anti-shock functions
Built-in track cross counter                                                   Digital input pins
Traverse speed detection function

(Digital Signal Processing)

Built-in DSL and PLL
Frame synchronization detection, holding, and
insertion
Subcode data processing

Subcode Q data CRC check
Built-in subcode Q data register

CIRC error detection and correction

C1 decoder: duplex error correction
C2 decoder: triplex error correction
Built-in 16-K bits of RAM for use in de-

interleaving

Audio data interpolation

Averaging or retention of previous values
Digital attenuation (–12 dB)

Audio data peak level detection function
Digital audio interface (EIAJ format)
Audio data serial interface for input and output

(Spindle Motor Servo)

CLV digital servo
Switchable servo gain

MN662790RSA1

Signal Processing LSI for CD Players

(Audio circuits)

Digital filter using 8-fold oversampling
Built-in D/A converter (1-bit D/A converter)
Built-in differential operational amplifier (secondary

low pass filter)

(Other)

Built-in playback pitch control function (normal

speed only) (

±

13%)

Support for quadruple-speed playback (digital servo

and signal processing block only)

Built-in support for jitter-free disc rotation synchro-

nization playback

Oscillator shutdown mode
Power management mode
Operating voltage 3.3 V for internal circuit; 5 V for

 Applications

 CD players

15

MN662790RAS1

 Pin Assignment

QFS080-P-1414

(TOP VIEW)

BYTCK/TVSTOP

CLDCK

FCLK

IPFLAG

FLAG

CLVS

CRC

DEMPH

FLAG6/RESY

IOSEL

TEST

AV

DD1

OUTL
AV

SS1

OUTR

RSEL
CSEL

PSEL

MSEL

SSEL

V

DD

X2

X1

V

SS

SBCK

SUBC

VCOF2

PCK

EFM

AV

SS2

AV

DD2

VCOF

PLLF

DSLF

DRF

I

REF

ARF

WVEL

PLAY

PLLF2

BCLK

LRCK

SRDATA

DV

DD1

DV

SS1

TX

MCLK

MDATA

MLD

SENSE

FLOCK

TLOCK

BLKCK

SQCK

SUBQ

DMUTE

STAT

RST

SMCK

PMCK

LDON
BDO
RFDET
TRCRS
OFT
VDET
RFENV
TE
FE
TBAL
FBAL
V

REF

FOD
TRD
KICK
ECS
ECM
PC
TVD
TRV

61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80

40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21

60

59

58

57

56

55

54

53

52

51

50

49

48

47

46

45

44

43

42

41

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

16