QS7785PF/CF
NIPPON PRECISION CIRCUITS--1
NIPPON PRECISION CIRCUITS INC.
3D 2/4-Channel Stereo Surround Synthesizer
OVERVIEW
The QS7785PF/CF is an audio processor IC that
generates 2, 4, 5-channel stereo surround signals
from 2-channel stereo or mono sources using QSur-
roundTM technology developed and licensed by
QSound Labs, Inc.
It can create 2-channel left and right surround effect
signal for front speakers, and a rich enhanced sur-
round signal using front speakers and surround
speakers for 4-channel output. It also features a cen-
ter signal output for clear listening of vocal and
speech signals.
FEATURES
I
Surround signal output for 2-channel front speak-
ers
I
Surround signal output for 4-channel front + sur-
round speakers
I
Center speaker output for voice signals
I
Parallel and 2 serial interfaces for mode control
supported
QS7785CF: I
2
C bus 2-wire serial interface
(Data and Clock)
QS7785PF: 3-wire serial interface (Data, Clock
and Strobe)
I
5 to 13V analog supply
I
4.5 to 5.5V digital supply
I
48-pin QFP package
APPLICATIONS
I
TV, radio and VCRs
I
Car audio
I
Multimedia products
PINOUT
(Top view)
QS7785PF
QS7785CF
ORDERING INFORMATION
I
2
C bus is a registered trademark of Philips Electronics N.V.
Dolby and the double-D symbol are registered trademarks of Dolby Laboratories Licensing Corporation.
38
39
40
41
42
43
44
45
46
47
48
1
2
3
4
5
6
7
8
9
10
11
13
14
15
16
17
18
19
20
21
22
23
26
27
28
29
30
31
32
33
34
35
36
LIN
BASC2
MSC6
MSC5
MSC4
MSC3
MSC2
MSC1
QXCC1
QXCC2
QXCC3
SLOUT
COUT
CIN
LPC
VREFIN
N.C.
VREFOUT
PSAVE
MUTE
BASS
SUR(SCL)
QXCC4
QXDC1
QXDC2
QXDC3
QXDC4
GND
VDD
P/S
SP(STRB)
MONO
AC
BASC1
QXAC1
QXAC2
QXAC3
QXAC4
VCC
QXBC1
QXBC2
QXBC3
QXBC4
FROUT
12
BYP(SDA)
24
SROUT
37
RIN
25
FLOUT
QS7785PF
38
39
40
41
42
43
44
45
46
47
48
1
2
3
4
5
6
7
8
9
10
11
13
14
15
16
17
18
19
20
21
22
23
26
27
28
29
30
31
32
33
34
35
36
LIN
BASC2
MSC6
MSC5
MSC4
MSC3
MSC2
MSC1
QXCC1
QXCC2
QXCC3
SLOUT
COUT
CIN
LPC
VREFIN
N.C.
VREFOUT
PSAVE
MUTE
BASS
SUR(SCL)
QXCC4
QXDC1
QXDC2
QXDC3
QXDC4
GND
VDD
P/S
SP
MONO
AC
BASC1
QXAC1
QXAC2
QXAC3
QXAC4
VCC
QXBC1
QXBC2
QXBC3
QXBC4
FROUT
12
BYP(SDA)
24
SROUT
37
RIN
25
FLOUT
QS7785CF
Device
Package
QS7785PF
48-pin QFP
QS7785CF
48-pin QFP
QS7785PF/CF
NIPPON PRECISION CIRCUITS--2
PACKAGE DIMENSIONS
(Unit: mm)
BLOCK DIAGRAM
0.19 0.05
0.10
0.07
0.10
0.17 0.05
0 to 10
1.50
0.10
0.20
0.08
M
0.50
0.35max
1.00typ
7.00 0.20
9.00 0.20
7.00
0.20
9.00
0.20
0.50 0.10
0.339typ
BASC1
VCC
Serial I/O
Front
QEXPANDER
QXAC2
QXAC4
QXBC2
QXBC4
QXCC1
QXCC3
QXDC1
Mono to
Stereo
Multiplex/Decode/Level Shift
CIN
VREFIN
GND
29
32
34
27
46
48
2
4
31
6
19
36
21
QXBC3
28
QXBC1
30
QXAC3
33
QXAC1
35
QXCC2
47
QXCC4
1
3
5
QXDC2
QXDC3
QXDC4
Surround
QEXPANDER
RIN
37
LIN
38
BASC2
39
MSC6
40
MSC5
41
MSC4
42
MSC3
43
MSC2
44
MSC1
45
COUT
22
LPC
20
SLOUT
23
SROUT
24
FLOUT
25
FROUT
26
To internal
VREFOUT
17
PSAVE
16
MUTE
15
BASS
14
MONO
10
AC
11
SP(STRB)
9
SUR(SCL)
13
BYP(SDA)
12
N.C.
18
VDD
7
P/S
8
To internal
QS7785PF/CF
NIPPON PRECISION CIRCUITS--3
PIN DESCRIPTION
Number
Name
I/O
Description
Parallel
Serial
1
QXCC4
O
QEXPANDER C capacitor 4
2
QXDC1
I
QEXPANDER D capacitor 1
3
QXDC2
O
QEXPANDER D capacitor 2
4
QXDC3
I
QEXPANDER D capacitor 3
5
QXDC4
O
QEXPANDER D capacitor 4
6
GND
Ground
7
VDD
4.5 to 5.5V digital supply
8
P/S
I
Input mode control (HIGH: parallel, LOW: serial)
9
SP
I
Enhancement control (HIGH: high spread, LOW: low spread)
STRB
I
Serial data strobe (not applicable to QS7785CF)
10
MONO
I
Mono-to-stereo convert select (HIGH: mono to stereo mode, LOW: normal mode)
11
AC
I
Center output control (HIGH: center on, LOW: center off)
12
BYP
I
Bypass control (HIGH: bypass, LOW: Qsurround)
SDA
I/O
Serial data input (also serves as ACK signal output for I
2
C bus)
13
SUR
I
Surround speaker control (HIGH: surround speaker on, LOW: off)
SCL
I
Serial clock signal input
14
BASS
I
Bass boost mode control (HIGH: bass boost on, LOW: bass boost off)
15
MUTE
I
Mute signal control (HIGH: mute on, LOW: mute off)
16
PSAVE
I
Power save control (HIGH: power save on, LOW: power save off)
17
VREFOUT
O
V
CC
/2 reference voltage output
18
NC
No connection
19
VREFIN
I
V
CC
/2 reference voltage output (biased internally to V
CC
/2)
20
LPC
I
Center output lowpass filter
21
CIN
I
COUT output signal feedback input for front-channel output
22
COUT
O
Center signal output
23
SLOUT
O
Surround left-channel signal output
24
SROUT
O
Surround right-channel signal output
25
FLOUT
O
Front left-channel signal output
26
FROUT
O
Front right-channel signal output
27
QXBC4
O
QEXPANDER B capacitor 4
28
QXBC3
I
QEXPANDER B capacitor 3
29
QXBC2
O
QEXPANDER B capacitor 2
30
QXBC1
I
QEXPANDER B capacitor 1
31
VCC
5 to 13V DC analog supply
32
QXAC4
O
QEXPANDER A capacitor 4
33
QXAC3
I
QEXPANDER A capacitor 3
34
QXAC2
O
QEXPANDER A capacitor 2
35
QXAC1
I
QEXPANDER A capacitor 1
36
BASC1
I
Bass boost right-channel signal input
QS7785PF/CF
NIPPON PRECISION CIRCUITS--4
SPECIFICATIONS
Absolute Maximum Ratings
GND = 0V
Recommended Operating Conditions
GND = 0V
37
RIN
I
Right-channel signal input
38
LIN
I
Left-channel signal input
39
BASC2
I
Bass boost left-channel signal input
40
MSC6
I
Mono/stereo conversion filter capacitor 6
41
MSC5
I
Mono/stereo conversion filter capacitor 5
42
MSC4
I
Mono/stereo conversion filter capacitor 4
43
MSC3
I
Mono/stereo conversion filter capacitor 3
44
MSC2
I
Mono/stereo conversion filter capacitor 2
45
MSC1
I
Mono/stereo conversion filter capacitor 1
46
QXCC1
I
QEXPANDER C capacitor 1
47
QXCC2
O
QEXPANDER C capacitor 2
48
QXCC3
I
QEXPANDER C capacitor 3
Parameter
Symbol
Rating
Unit
Supply voltage range (analog)
V
CC
-
0.3 to 15
V
Supply voltage range (digital)
V
DD
-
0.3 to 7
V
Input voltage range (analog)
V
IANA
-
0.3 to V
CC
+ 0.3
V
Input voltage range (digital)
V
IDIG
-
0.3 to V
DD
+ 0.3
V
I
2
C signal input voltage (SDA, SCL)
V
IOPEN
10
V
Power dissipation
P
D
250
mW
Storage temperature range
T
stg
-
40 to 125
C
Parameter
Symbol
Rating
Unit
Supply voltage range (analog)
V
CC
5 to 13
V
Supply voltage range (digital)
V
DD
4.5 to 5.5
V
Operating temperature range
T
opr
-
20 to 85
C
Number
Name
I/O
Description
Parallel
Serial
QS7785PF/CF
NIPPON PRECISION CIRCUITS--5
DC Characteristics
V
CC
= 9V, V
DD
= 5V, GND = 0V, Ta = 25
C
Noise and THD Characteristics
V
CC
= 9V, V
DD
= 5V, GND = 0V, Ta = 25
C
Parameter
Symbol
Condition
Rating
Unit
min
typ
max
Analog input impedance
Z
AIN1
LIN, RIN
16
20
24
k
Z
AIN2
CIN
8
10
12
Reference voltage output
V
REFOUT
V
CC
/2
V
HIGH-level input voltage
V
IH
0.7V
DD
V
LOW-level input voltage
V
IL
0.3V
DD
V
Input leakage current
I
LEAK
Digital inputs, V
DD
input voltage
-
3
3
A
I
ILOPD
SDA, SCL, 10V input voltage
-
3
3
LOW-level output voltage
V
OL
ACK signal output from SDA, 3mA sink
current
0
0.4
V
Supply voltage (analog)
V
CC
5
13
V
Supply voltage (digital)
V
DD
4.5
5.5
V
Current consumption (analog)
I
CC
6
8
mA
Current consumption (digital)
I
DD
0.3
0.5
mA
Standby current (analog)
I
CCSAVE
0.1
0.2
mA
Parameter
Symbol
Condition
Rating
Unit
min
typ
max
Bypass noise voltage
N
BYP
BYP = HIGH, SUR = MONO = SP = LOW,
"A"-wgt, FLOUT, FROUT
10
20
V
RMS
Qsurround noise voltage (front)
N
QSF
SUR = SP = HIGH, BYP = MONO = LOW,
"A"-wgt, FLOUT, FROUT
20
40
V
RMS
Qsurround noise voltage (surround)
N
QSR
SUR = SP = HIGH, BYP = MONO = LOW,
"A"-wgt, SLOUT, SROUT
15
30
V
RMS
Bypass total harmonic distortion
THD
B
BYP = SUR = HIGH, MONO = SP = LOW,
LIN = RIN = 1V
RMS
, f = 1kHz, FLOUT,
FROUT, SLOUT, SROUT
0.1
%
Qsurround mono total harmonic
distortion
THD
QM
BYP = LOW, SUR = MONO = SP = HIGH,
LIN = RIN = 1V
RMS
, f = 1kHz, FLOUT,
FROUT, SLOUT, SROUT
0.1
%
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