CXA1897Q
Dolby B Type Noise Reduction System with Recording/Playback Equalizer
Description
The CXA1897Q is an analog signal processing IC
for tape recorders. It achieves whole processing
operations for the recording and playback systems
which include the Dolby B noise reduction function
on a single chip. This IC supports 2 channels at
each function.
Features
• Dolby B noise reduction supports 1.7 times normal
speed.
• Recording/playback equalizer amplifier supports
1.7 times normal speed.
• Built-in comparator for AMS (automatic music
sensor)
• Built-in AGC (automatic gain control) with amplifier
for MPX filter.
• Playback equalizer outputs independently for
DECK-A and DECK-B.
• Externally adjustable recording equalizer Gp and
fp.
• Built-in Recording mute function.
• Double cassette dubbing system can be easily
configured just with this IC.
48 pin QFP (Plastic)
Absolute Maximum Ratings (Ta=25°C)
• Supply voltage
VCC
12
• Operating temperature Topr –20 to +75
• Storage temperature
Tstg –65 to +150
• Allowable power dissipation
PD
735
Operating Conditions
• Supply voltage
VCC
6.5 to 10.0
V
°C
°C
mW
V
Applications
All analog signal processing in cassette deck parts
of tape recorders and compact music centers
(Sankyo Seiki mfg. Co., Ltd. YK47R-KF202 or
equivalent which has the same head type.)
Structure
Bipolar silicon monolithic IC
∗ These ICs are available only to the licensees of Dolby Laboratories Licensing Corporation from whom licensing and applications
information may be obtained.
∗ "Dolby" and the double D symbols are trade marks of Dolby Laboratories Licensing Corporation.
Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by
any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the
operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits.
—1—
E93930D78
CXA1897Q
GND
GND
+
PB OUTB2
PB FB12
PB INB2
PB INA1
PB INA2
+
PB INB1
+
PB FB11
PB OUTB1
+
PB OUTA1
PB FB21
GND
DECK A
PB HEAD
PB FB22
PB OUTA2
GND
GND
Block Diagram
28
NR
NR
+
26
RECEQ
CTL
FP CAL
GP CAL
SPEED
REC OUT2
REC OUT1
(N/Cr/Me)
+
GND GND
PB
PB
REC
REC
DECK B
R/P HEAD
—2—
+
+
REC IN
REC IN
+
20 21 22 23 24
GND GND
GND
GND
GND GND
DECK
A/B
DECK (120/70us)
A EQ
DECK B EQ
+
D R OUT1
13 14 15 16 17 18 19
D R OUT2
TC
+
GND
12
PBEQ
CTL
25
+
11
GND
REC
MUTE
D PB IN2
DOLBY NR
REC/PB
27
10
GND
+
REC
EQ
+
REC
EQ
9
+
29
TC
D L OUT2
GND
8
D IREF
AGC IN
MPX
AGC
30 OUT
D REC IN2
MUTE
IREF
32
AGC TC
31
D REC IN1
D PB IN1
GNDGND GND
Vcc
40k
AGC
7
33
10k
10dB
AMP
GND
AMS
40k
10dB
AMP
+
10k
IREF
+
+
6
AGC
OUT
IREF
34 VG
+
MPX
GND
4
5
35
+
AMS GAIN
36
+
3
AGC IN
GND
DOLBY NR
ON/OFF/HI
D L OUT1
GND
RFC 2
+
GND
1
+
AMS
OUT
Vcc
GND
Vcc
GND
GND
GND
GND
GND
GND
GND
48 47 46 45 44 43 42 41 40 39 38 37
CXA1897Q
36
35
34
33
32
31
30
29
28
27
26
25
GND
IREF
VG
AGC TC
AGC IN2
AGC OUT2
D RECIN2
REC MUTE
D PBIN2
MODE
D L OUT2
D TC2
Pin Configuration
37 PB OUTB2
D R OUT2 24
38 PB OUTA2
REC IN2 23
39 PB FB22
GP CAL 22
40 PB FB12
FP CAL 21
41 PB INB2
SPEED 20
42 PB INA2
REC OUT2 19
CXA1897Q
43 PB INA1
REC OUT1 18
44 PB INB1
B EQ 17
45 PB FB11
A EQ 16
AGC OUT1
D RECIN1
D IREF
D PBIN1
NRSW
D L OUT1
D TC1
D R OUT1 13
AGC IN1
48 PB OUTB1
AMS GAIN
REC IN1 14
AMS OUT
47 PB OUTA1
RFC
DECK AB 15
Vcc
46 PB FB 21
1
2
3
4
5
6
7
8
9
10
11
12
—3—
CXA1897Q
Pin Description
Pin
No.
1
Symbol
Vcc
(Ta=25°C, Vcc=8 V, no signals)
DC
I/O
voltage I/O resistance
8.0V
—
Equivalent circuit
1
—
Description
Vcc
Vcc
Power supply pin.
Vcc
×3
2
RFC
8.0V
—
—
Connects the resistor and
capacitor for providing a ripple
eliminated stable voltage in
the power supply.
×3
2
×250
147
to RFS
GND
AMS output pin.
Connects the resistor and
capacitor which determine the
attack and recovery time
constants of the output to Vcc.
Vcc
3
AMS OUT
8.0V
O
3
—
147
×2
No signal supplied → High
level
Signal supplied → Low level
GND
Vcc
Vcc
5p
147
4
AMS GAIN 2.8V
—
—
4
Connects the resistor which
determines the AMS signal
detection level.
×2
10k
GND
Vcc
Vcc
5 AGC IN1
32 AGC IN2
4.0V
I
50kΩ
147 10k
5
32
40k
×4
VGS
GND
—4—
AGC signal input pin.
The input resistance varies
from 50kΩ to 10kΩ.
AGC is applied when a signal
of –30dB or more level is input
to AGC.
(Pin 33 external 47µF //
300kΩ)
CXA1897Q
Pin
No.
Symbol
DC
I/O
voltage I/O resistance
Equivalent circuit
Vcc
Vcc
×2
6 AGC OUT1
31 AGC OUT2
4.0V
O
147Ω
Description
147
500
6
AGC output pin.
500
31
10k
21k
5k
VGS
×4
GND
Vcc
Vcc
7 D RECIN1
30 D RECIN2
4.0V
I
40kΩ
Dolby NR recording
(encoding) input pin.
7
9
147
28
30
9 D PBIN1
28 D PBIN2
4.0V
I
40k
40kΩ
VGS
15k
Dolby NR playback (decoding)
input pin.
15k VGS
GND
Vcc
Vcc
Connects the 18kΩ resistor for
providing the reference
current of the Dolby NR
section internal filter.
×2
8
D IREF
1.2V
—
—
4k
147
8
×4
GND
Vcc
Vcc
10 NRSW
2.5V
(For
OPEN)
I
53kΩ
147 50k
5k
10
5k
GND
GND
—5—
Dolby NR ON/OFF switch.
Low :
ON
Medium :OFF
High :
1.7 times normal
speed
CXA1897Q
Pin
No.
Symbol
DC
I/O
voltage I/O resistance
Equivalent circuit
Vcc
Description
Vcc
×2
147
11 D L OUT1
26 D L OUT2
4.0V
O
147Ω
6k
200
11
26
Dolby NR line (decoding)
output pin.
200
×10
GND
GND
Vcc
Vcc
×2
12 D TC1
25 D TC2
0.3V
—
—
Connects the capacitors
(0.1µF) which determine the
time constants of the input
signal level detector.
20k
12
25
147
700k
GND
GND
Vcc
Vcc
10k
×2
300
147
13 D R OUT1
24 D R OUT2
4.0V
O
147Ω
13
24
13k
Dolby NR recording
(encoding) output pin.
300
×10
GND
GND
Vcc
Vcc
147
14 REC IN1
23 REC IN2
4.0V
I
50kΩ
14
23
23k
Recording equalizer input pin.
50k
1.8k
VGS
VGS
GND
GND
—6—
CXA1897Q
Pin
No.
Symbol
DC
I/O
voltage I/O resistance
Equivalent circuit
Description
15 Playback input deck A/B
Vcc
15
16
20
27
DECK AB
A EQ
SPEED
MODE
—
I
15
16
20
27
—
Vcc
147
GND
GND
Vcc
Vcc
17 B EQ
2.5V
(For
OPEN)
I
53kΩ
selector switch
Low : PB INA
High : PB INB
16 Deck A equalizer selector
switch.
Low : 120µs EQ
High : 70µs EQ
20 R e c o r d i n g / p l a y b a c k
equalizer speed selector
switch.
Low : Normal speed
High : High speed
(1.7 times normal speed)
27 Dolby NR mode selector
switch.
Low : Recording
(encoding)
High : Playback (decoding)
Deck B equalizer selector
switch.
Low :
Normal tape, 120µs
EQ
Medium : CrO2 tape, 70µs EQ
High :
Metal tape, 70µs
EQ
5k
147 50k
17
5k
GND
GND
Vcc
Vcc
×3
40k
500
18 REC OUT1
19 REC OUT2
4.0V
O
147Ω
18
19
×2
500
147
×10
GND
GND
—7—
5p
Recording equalizer output.
CXA1897Q
Pin
No.
Symbol
DC
I/O
voltage I/O resistance
Equivalent circuit
Description
Vcc
Vcc
21 FP CAL
×2
—
—
21
35
35 IREF
147
5p
1.2V
GND
GND
Vcc
22 GP CAL
1.2V
—
Vcc
—
Connects the resistor to
determine the high-band peak
gain of the recording
equalizer.
Reference setting resistance
is 27kΩ.
×2
22
30k
147
GND
GND
Vcc
Vcc
50µA
20k
20k
×2
×2
29 REC MUTE
—
I
—
Connects the resistor to
determine the high-band peak
frequency of the recording
equalizer.
Reference setting resistance
is 27kΩ.
Connects the 12kΩ resistor to
determine each gain of the
equalizers.
147
29
2.7V
GND
Recording mute ON/OFF
selector switch.
Low : Muting ON
High :Muting OFF
∗ Fader function can be
achieved with an external
time constant circuit.
GND
Vcc
Vcc
×2
×2
33 AGC TC
0.0V
—
—
Connects the resistor and
capacitor to determine the
attack and recovery time
constants of the AGC.
500
200
33
147
500
×2
5k
100k
200
GND
GND
Vcc
Vcc
30k
×2
×2
34 VG
4.0V
—
60kΩ
34
500 V
S
G
500
147
45k
×4
30k
GND
GND
—8—
Signal reference voltage.
Connects the capacitor for
eliminating ripple.
CXA1897Q
Pin
No.
Symbol
DC
I/O
voltage I/O resistance
Equivalent circuit
Description
36
36 GND
0.0V
—
—
Vcc
43
42
44
41
PB INA1
PB INA2
PB INB1
PB INB2
45 PB FB11
40 PB FB12
0.0V
I
GND pin.
GND
70kΩ
Vcc
10k
RFS
Vcc
10k
Playback equalizer input
pin.
1k
1.4V
—
105kΩ
43
42
44
41
1k
×6
147
210k
5p
×2
×6
147
Playback equalizer
negative feedback pin.
210k
GND
GND
RFS
Vcc
2k
2k
×4
2.8V
—
—
7k
×3
147
46
39
GND
Vcc
×4
Connects the capacitors which
determine the 120µs, 70µs or
other time constant of the
playback equalizer.
×3
GND
GND
Vcc
RFS
ON/OFF
ON/OFF
×3
47
38
48
37
45
40
70k
GND
46 PB FB21
39 PB FB22
Vcc
PB OUTA1
PB OUTA2 2.8V
PB OUTB1
PB OUTB2
O 147Ω
50kΩ
47
38
48
37
5k
5k
147
50k
500
×6
GND
×2
×2
500
GND
—9—
Playback equalizer output pin.
The pin selected by the deck
AB switching has a low output
resistance; the other pin has a
50kΩ output resistance.
CXA1897Q
Electrical Characteristics
(Ta=25°C, VCC=8.0V)
Item
Conditions
Operating voltage
Current consumption
AGC
Item
AMS
Conditions
Typ.
Max.
Unit
6.5
8.0
10.0
V
15.0
19.5
24.0
mA
Min.
Typ.
Max.
Unit
–22.5 –20.0
dBm
AGC on output level
1kHz, –25dBm, AGC TC external 47µF // 300kΩ
–24.0
AGC on channel balance
1kHz, –15dBm, AGC TC external 47µF // 300kΩ
–2.0
0.0
2.0
dB
AGC on distortion
1kHz, 0dBm, AGC TC external 47µF // 300kΩ
—
0.1
1.5
%
Min.
Typ.
Max.
Unit
—
—
–23.0
dB
Min.
Typ.
Max.
Unit
dBm
Item
No signal detection
level
Item
Playback equalizer amplifier block
No signal
Min.
Conditions
AMS GAIN=4.7kΩ, 1kHz
Reference output level for PB equalizer system
(–25.0dBm)
Conditions
f=315Hz, Vin=–70dBm reference level
–27.0
–25.0 –23.0
f=2.7kHz, Vin=–58.5dBm, against 315Hz
–1.5
–0.1
1.5
dB
70µs NORM mode
frequency characteristics
f=4.5kHz, Vin=–53.8dBm, against 315Hz
–1.5
0.3
1.5
dB
120µs HIGH mode
frequency characteristics
f=5.3kHz, Vin=–52.5dBm, against 315Hz
0.1
1.3
3.1
dB
70µs HIGH mode
frequency characteristics
f=9.1kHz, Vin=–47.8dBm, against 315Hz
0.1
1.6
3.1
dB
Signal handling
120µs-NORM mode, f=1kHz, RL=2.7kΩ, THD+N=1%
–10.0
–6.0
—
dBm
Total harmonic distortion
120µs-NORM mode, f=1kHz, RL=2.7kΩ, Vin=–52dBm
—
0.3
0.7
%
S/N ratio
120µs-NORM mode, Rg=2.2kΩ, "A" WTG filter
55
62
—
dB
Output offset voltage
120µs-NORM, Rg=70kΩ
2.40
2.70
3.20
V
120µs NORM mode
frequency characteristics
—10—
CXA1897Q
Item
Recording equalizer amplifier block
Reference input level
Reference output level
S/N ratio
Signal handling
Total harmonic distortion
Output offset voltage
NORM-NORM mode
frequency characteristics
CrO2-NORM mode
frequency characteristics
METAL-NORM mode
frequency characteristics
NORM-HIGH mode
frequency characteristics
CrO2-HIGH mode
frequency characteristics
METAL-HIGH mode
frequency characteristics
Maximum muting amount
Muting characteristics
Conditions
NORM-NORM, 315Hz
NORM-NORM, 315Hz
Rg=5.1k, "A"-WTG filter
NORM-NORM, RL=2.7kΩ, 1kHz, THD=1%
NORM-NORM, RL=2.7kΩ, 1kHz, 0dB
NORM-NORM
3kHz, –20dB
Against NORM-NORM
mode at 315Hz, –20dB
8kHz, –20dB
12kHz, –20dB
3kHz, –20dB
Against NORM-NORM
mode at 315Hz, –20dB
8kHz, –20dB
12kHz, –20dB
3kHz, –20dB
Against NORM-NORM
mode at 315Hz, –20dB
8kHz, –20dB
12kHz, –20dB
Against NORM-NORM
5kHz, –20dB
mode at 315Hz, –20dB
15kHz, –20dB
20kHz, –20dB
Against NORM-NORM
5kHz, –20dB
mode at 315Hz, –20dB
15kHz, –20dB
20kHz, –20dB
Against NORM-NORM
5kHz, –20dB
mode at 315Hz, –20dB
15kHz, –20dB
20kHz, –20dB
NORM-NORM mode, 1kHz, +8dB
NORM-NORM mode, 1kHz,
2.0V (MUTE pin voltage)
—11—
Min.
Typ.
Max.
Unit
–29.4 –27.9 –26.4
—
–10.0
—
57.0 60.6
—
8.0
8.8
—
—
0.2
0.5
3.6
4.0
4.4
–1.3 –0.2
1.1
3.7
5.7
7.3
10.4 13.4 16.4
1.8
3.0
4.2
6.7
8.4
9.7
13.2 15.8 18.2
3.3
4.5
5.7
5.9
7.4
8.9
11.3 13.7 15.8
–0.7
0.2
1.7
8.3
10.5 12.3
13.5 16.7 19.5
3.6
4.9
6.0
12.0 14.2 16.0
17.0 20.0 22.5
4.9
6.1
7.3
10.5 12.4 14.0
14.7 17.4 19.7
—
–100 –80
–8.0 –5.6 –4.0
dBm
dBm
dB
dB
%
V
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
Item
PB IN input sensitivity
REC IN input sensitivity
LINEOUT level
Dolby level
Encode boost 1-(1)
Encode boost 1-(2)
Encode boost 1-(3)
Encode boost 1-(4)
Encode boost 1-(5)
Encode boost 2-(1)
Encode boost 2-(2)
Encode boost 2-(3)
Signal handling
Total harmonic distortion (1)
Total harmonic distortion (2)
Encode S/N ratio
(REC-PB)
(PB-REC)
(REC 1ch-2ch)
(PB 1ch-2ch)
Cross talk
Dolby block
CXA1897Q
Conditions
PB, NR-OFF, 1kHz, D-R-OUT –10dBm
REC, NR-OFF, 1kHz, D-R-OUT –10dBm
REC, NR-OFF, 1kHz, D-R-OUT –10dBm
DOLBY NR REC OUT pin (0dB)
REC, NR-ON, 500Hz –25dB
REC, NR-ON, 2kHz –25dB
REC, NR-ON, 5kHz –25dB
REC, NR-ON, 10kHz, –40dB
REC, NR-ON, 10kHz 0dB
REC, NR-¥1.7 times, 850Hz –25dB
REC, NR-¥1.7 times, 8.5kHz –25dB
REC, NR-¥1.7 times, 17kHz –40dB
REC, NR-OFF, 1kHz, THD+N=1%
REC, NR-OFF, 1kHz, 10dB
REC, NR-ON, 1kHz, 10dB
REC, NR-ON, CCIR-filter
PB, NR-OFF, 1kHz, 0dB
REC, NR-OFF, 1kHz, 0dB
REC, NR-OFF, 1kHz, 0dB
REC, NR-OFF, 1kHz, 0dB
—12—
Min.
Typ.
Max.
Unit
–32
–32
–7
—
1.4
5.5
3.9
9.7
–1.1
1.4
3.9
9.7
14.0
—
—
65.0
—
—
—
—
–30
–30
–6
–10
3.0
6.3
5.0
10.6
0.7
3.1
5.1
10.4
15.5
0.01
0.03
66.5
—
—
—
—
–28
–28
5
—
4.4
8.5
6.9
11.9
1.9
4.4
6.9
11.9
—
0.2
0.2
—
–65
–60
–55
–55
dBm
dBm
dBm
dBm
dB
dB
dB
dB
dB
dB
dB
dB
dB
%
%
dB
dB
dB
dB
dB
CXA1897Q
Item
Control voltage "L" level 1
Control voltage "M" level 1
Control voltage "H" level 1
Control voltage "L" level 2
Control voltage "H" level 2
Control voltage "L" level 3
Control voltage "H" level 3
Conditions
NRSW (10PIN), B EQ (17PIN)
NRSW (10PIN), B EQ (17PIN)
NRSW (10PIN), B EQ (17PIN)
REC MUTE (29PIN)
REC MUTE (29PIN)
Other control pins
Other control pins
Min.
0.0
2.2
4.2
0.0
3.5
0.0
2.5
Typ.
—
—
—
—
—
—
—
Max. Unit
0.5
V
2.8
V
Vcc
V
0.5
V
Vcc
V
0.5
V
Vcc
V
Note)
NORM-NORM :
CrO2-NORM :
METAL-NORM :
120µs-NORM :
70µs-NORM :
NORMAL TAPE-NORMAL SPEED
CrO2 TAPE-NORMAL SPEED
METAL TAPE-NORMAL SPEED
EQ=120µs-NORMAL SPEED
EQ=70µs-NORMAL SPEED
—13—
NORM-HIGH :
CrO2-HIGH :
METAL-HIGH :
120µs-HIGH :
70µs-HIGH :
NORMAL TAPE-HIGH SPEED
CrO2 TAPE-HIGH SPEED
METAL TAPE-HIGH SPEED
EQ=120µs-HIGH SPEED
EQ=70µs-HIGH SPEED
DC Ammeter
Vcc
Power
Supply
GND
A
C1
5V
GND
1.2k
R3*
R4*
R5*
R6*
R7*
R8*
R9*
R10*
1.2k
R2*
to Each SW
R1*
22µ/25V
68k
27k
68k
27k
27k
68k
27k
68k
2.7k
R12*
C13
4.7µ/25V
R18*
180
47µ /25V R16*
S6A
2.2k C11
0.1µ
C5
S1 R15* 4.7µ/25V
S6B
2.2k C10
0.1µ
S2 4.7µ/25V
C4
C3
S3 4.7µ/25V
0.1µ
2.2k C9
S6C
S4 R14* 4.7µ/25V
C2 0.1µ
2.2k C8
S6D
R13* R17*
C6
C7
S5A
S5B
180
R11*
C12
2.7k 4.7µ/25V
47µ/25V
C15*
3.5V
V5
27
28
29
30
31
32
+
33
+
+
+
+
+
1
1k
R19*
48 PB OUTB1
+
8
7
6
9
GND
AC
V6
10
REC IN1
47 PB OUTA1
5
14
DECK AB
46 PB FB21
4
15
A EQ
45 PB FB11
3
16
B EQ
44 PB INB1
2
17
REC OUT1
12
11
D R OUT1
18
REC OUT2
42 PB INA2
43 PB INA1
19
SPEED
41 PB INB2
13
20
FP CAL
21
22
23
24
0.018µ
40 PB FB12
GP CAL
39 PB FB22
D R OUT2
25
26
PB
REC IN2
+
C42
38 PB OUTA2
37 PB OUTB2
34
35
+
36
0V
C17
Audio
SG
C16 100µ/25V
0.015µ
V4
Vcc
0.1µ
+
V3
C18
+
2V
47µ/25V
C20
2.2µ/25V
V2
R21
4.5V 2.5V
0.1µ
C19
AGC OUT1
C14*
R20*
S7A
AGC IN1
100k
R22*
C23
0.47µ 4.7k
C24
R24*
S7B
D RECIN1
10k
AMS GAIN
5.1k
R26*
D IREF
C28
R28*
S9 4.7µ/25V
C30
330k 0.1µ
R30*
S10B R32*
240k
5.1k 4.7µ/25V
R34*
C33 18k
S15
C35
0.1µ
S10D R39*
5.1k 4.7µ/25V
R36*
R38* 330k
V1
C38
X1.7 S17
DL OUT1
R43 4.7µ/25V
1k
C54
10k
R53* S24E
C53
C50
C43
C48
C49
C45
R56
S24A
S24B
NORM S25
HIGH
100k
*R59
R51*
C51
R50*
10k S24F
S24D
C55
S10F
0.1µ
10k
4.7µ/25V
4.7µ/25V
S23
5.1k
R46* 1k
4.7µ/25V
R54
*R58
100k
DECK A S30
DECK B
METAL S26
Cr02 S27
S28
1k
NORM
R55 120µS S29
4.7µ/25V
70µS
1k
4.7µ/25V
C52
4.7µ/25V
2.7k
1k
R57
2.7k
4.7µ/25V
C47
R48*
C46 R47*
4.7µ/25V
4.7µ/25V
27k
R44*
27k
4.7µ/25V
C56
S22
C44
R49* 0.1µ
4.7µ/25V
5.1k S10E
R45*
10k S24C
R52*
4.7µ/25V
+
OFF S18
ON
0.015µ
12k
GND
C21
IREF
R23* 47µ/25V
AGC TC
D PBIN1
VG
RFC
R29*
AGC IN2
4.7µ/25V
C26
AGC OUT2
300k
ON S11
S12
D RECIN2
240k
C22 47µ/25V
AMS OUT
R25*
C25
330k
R31*
5.1k
4.7µ/25V
R27*
C27
10k
4.7µ/25V S8 C29
C31
0.1µ
R33*
S13
REC MUTE
NRSW
0.1µ
D L OUT2
OFF
D PBIN2
S56
C40
S20A
D TC2
D TC1
S40
10k
S39
10k
R60
S38
S57
S37
S36
S35
S34
S21
R61
10k
R62
10k
10k
R63
R64
10k
R65
R66
10k
10k
10k R67
R68
10k
R69
S33
S32
10k
R70
10k
S31
S49
S48
100
R72
100
S47
100
R73
S59
S46
S44
S45
S43
S58
R74
R75
100
100
R76
100
R77
R78
100
100
R79
100
R80
S42
S41
Amp
Oscillo
-scope
Distortion
Analyzer
AC
Voltmeter
CCIR
1kHz BPF
DIN Audio
"A"WTG
GND
GND
0dB or 30dB
DC
Voltmeter
R83
R71
R82
100
R81
100
50k
S50
REC
S16
4.7µ/25V
5.1k S10A 240k
C32
R35 4.7µ/25V
1k
R37*
C36 S14 C34
0.1µ 330k
4.7µ/25V R41* S10C R40*
240k
5.1k
C37
R42 4.7µ/25V
1k
MODE
+
+
*S20B
+
+
+
+
+
+
+
+
+
—14—
+
+
+
+
+
+
+
C39
+
+
+
+
S19
+
0.1µ
C41
+
0.018µ
+
+
Electrical Characteristics
Test Circuit
S55
S54
S53
S52
S51
CXA1897Q
CXA1897Q
1. Description of Control Mode
(1) Playback and recording equalizers
1) Playback equalizer (120µs/70µs)
A EQ (16 pin)
L
H
L
B EQ (17 pin)
M/H
DECK AB L
120µs
70µs
A EQ control complied with
(15 pin)
(A DECK)
(A DECK)
H B EQ control complied with
120µs
70µs
(B DECK)
(B DECK)
2) Recording equalizer (Normal, CrO2, Metal)
B EQ (17 pin)
REC MODE
L
Normal (Type I)
M
CrO2 (Type II)
H
Metal (Type IV)
3) Speed control
SPEED (20 pin)
Playback equalizer
Recording equalizer
L
Normal speed
Normal speed
H
1.7 times normal speed
1.7 times normal speed
4) Recording mute (29 pin)
Recording mute
Mute ON
Control voltage GND≤VCL≤0.5V
–7dB attenuation
Mute OFF
2.0V
3.5V≤VCH≤Vcc
The muting function is achieved by varying the gain of the recording equalizer amplifier as with an electric
volume, depending on the DC voltage level supplied to the REC MUTE pin.
Mute ON/OFF and the AGC ON/OFF are interlocked.
Rec Mute
AGC
Mute ON
OFF
Mute OFF
ON
Notes for executing the fader function
The recording mute and the AGC are interlocked and if the AGC is turned OFF, the AGC output level is
increased. Therefore, when the level of 3dB or more is input to the AGC to execute the fader function, the
natural characteristics cannot be obtained.
Take care of setting the input level to the AGC.
5) FP CAL (21 pin)
The standard setting resistance is 27kΩ. However, fo (Hz) is reduced by increasing and increased by
reducing this resistance.
6) GP CAL (22 pin)
The standard setting resistance is 27kΩ. However, the gain is increased by increasing or reduced by
reducing this resistance.
—15—
CXA1897Q
(2) Dolby B noise reduction
1) Dolby NR input mode
MODE (27 pin)
Input
Dolby NR
L
Rec In (7, 30 pin)
Encoding
H
Pb In (9, 28 pin)
Decoding
2) Dolby NR ON/OFF/×1.7
NRSW (10 pin)
Dolby NR
L
ON
M
OFF
—16—
H
×1.7
CXA1897Q
2. AMS
(1) AMS output logic
Detection status
AMS OUT
Signal detected
L
No signal detected
H
When the pins have been connected as shown on the
left figure,
Inside of IC
1
Vcc
Low : Approximately 0.3V (VCE (sat) voltage)
High : Vcc (V)
3
AMS OUT
36
GND
(2) AMS level setting
With the reference output level (–25dBm) of the playback equalizer as 0dB, consider at how many decibels the
AMS level is to be set.
(PBOUT2)
{ Vpeak (PBOUT1)+Vpeak
}
2
R (external resistance)
×5↔5µA
Compare
↓
R=
Vpeak (PBOUT1)+Vpeak (PBOUT2)
×106 — 1
2
Use formula 1 to determine external resistance R.
Ex. 1) To set the detection level at 20dB lower than the reference (calculated on the assumption that
1ch=2ch)
–25dBm–20dB=–45dBm=6.16mVpeak
R=6.16×10–3×106 ≈6.2kΩ
In which case, external resistance R is 6.2kΩ.
Ex. 2) To set the detection level at 30dB lower than the reference,
–25dBm–30dB=–55dBm=1.95mVpeak
R=1.95×10–3×106 ≈2kΩ
In which case, external resistance R is 2kΩ.
(3) AMS band setting
By inserting a capacitor in series with the external resistor determined in (2), the direct current of the AMS is
cut off. The lower end of the AMS band can be limited by adjusting the capacitor value because the cut-off
frequency of the high-pass filter is determined by this external resistor and capacitor.
—17—
CXA1897Q
Application Circuit
to LINE OUT2
0.1µ
4.7µ/25V
PB/REC
10k
10k
4.7µ/25V
31
30
29
28
27
26
D RECIN2
REC MUTE
D PBIN2
MODE
D L OUT2
25
D R OUT2 24
REC IN2 23
38 PB OUTA2
0.015µ
+
39 PB FB22
GP CAL 22
40 PB FB12
FP CAL 21
27k
27k
DECK A
PB HEAD
47µ/25V 180
SPEED 20
42 PB INA2
REC OUT2 19
4.7µ/25V
10k
150p
820p
CXA1897Q
44 PB INB1
B EQ 17
45 PB FB11
A EQ 16
46 PB FB21
DECK AB 15
10k
820p
AGC IN1
AGC OUT1
D RECIN1
D IREF
D PBIN1
NRSW
D L OUT1
5
6
7
8
9
10
11
12mH
2.2µ/25V
PB
NORM/CrO2
/METAL
GND
120µS/70µS
REC
GND
GND
DECK A
/DECK B
GND
22k
5.6k
22k
0.47µ
12
0.1µ
GND
4.7µ/25V
4.7µ/25V
10k
4.7µ/25V
GND GND GND
+
+
GND
to LINE OUT1
GND
D R OUT1 13
4.7µ/25V
GND
10k
–6dB
MPX
+
100p 18k
+
ON/OFF/X1.67
GND
+
4.7µ/25V
2.2µ/25V
VCC
47µ/25V
GND GND
AMS OUT
VCC
100µ/25V
+
0.47µ
100k
+
AGC IN1
0.015µ
+
1k
+
+
2.2µ/25V
D TC1
AMS GAIN
4
4.7µ/25V
AMS OUT
3
4.7µ/25V
RFC
2
4.7k
Vcc
1
48 PB OUTB1
10k
4.7µ/25V
10k
+
REC IN1 14
4.7µ/25V
10k
+
2.7k
47 PB OUTA1
REC
+
10k
10k
150p
+
+
REC OUT1 18
PB
Bias
12mH
12mH OSC
180p
2.2µ/25V
43 PB INA1
+
4.7µ/25V
180p NORM/HIGH
GND
10k
+
47µ/25V 180
+
2.2µ/25V
GND
GND
41 PB INB2
0.47µ
+
GND
5.6k
2.2µ/25V
10k
GND
22k
2.2µ/25V
DECK B
R/P HEAD
32
GND GND GND GND
33
22k
34
D TC2
ON/OFF
100p
10k
4.7µ/25V
4.7µ/25V
35
AGC OUT2
4.7µ/25V
+
36
37 PB OUTB2
GND
+
AGC IN2
+
+
AGC TC
+
+
VG
+
GND
IREF
+
–6dB
47µ/25V
1M
4.7µ/25V
33µ/25V
+
MPX
GND GND
+
2.7k 4.7µ/25V
GND GND
GND
+
10k
12mH
+
GND
12k
47µ/25V
GND GND GNDGND GND
AGC IN2
180p
GND
180p
Application circuits shown are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for
any problems arising out of the use of these circuits or for any infringement of third party patent and other right due to same.
—18—
CXA1897Q
Examples of representative characteristics
AGC output voltage characteristics
Quiescent current vs. Supply voltage
AGC OFF
Icc-Quiescent current (mA)
25
Output level (dBm)
0
20
–10
–20
AGC ON
15
–30
8
9
7
10
VCC-Supply voltage (V)
11
–40
–30
–20
–10
Input level (dBm)
0
Play back equalizer total harmonic distortion
AGC total harmonic distortion
0.5
1.0
Total harmonic distortion (%)
Total harmonic distortion (%)
Vcc=8V
AGC TC 47µF/300kΩ
f=1kHz
0.1
0.05
0.01
–40
–30
–20
–10
AGC Input level (dBm)
0
VCC=8V
RL=2.7kΩ
MODE 120µs-NS
f=1kHz
0.1
–30
–25
–20
–15 –10
Output level (dBm)
–5
–10
to 8V
–20
–30
20
50
100
200
500
1k
2k
Frequency (Hz)
—19—
5k
10k
20k
50k
AMS GAIN
3
4
+
0.47µ 4.7k
0
2.2µ
10
AMS OUT
VCC=8V
120µs-NS
AMS OUT 7V
0dB=–25dBm, 315Hz
(Playback equalizer reference output level)
100k
AMS Input level
(Playback equalizer output level) (dB)
AMS no signal detection level frequency response
GAIN (dB)
40
120µs-NS
120µs-HS
70µs-NS
70µs-HS
30
20
10
20
50
100
200
500
1k
2k
Frequency (Hz)
5k
10k
20k
50k
Recording equalizer frequency response
VCC=8V
0dB=NORM-NORM, 315Hz, –30dBm
(Tape) (Speed)
NORM-NORM
CrO2-NORM
METAL-NORM
NORM-HIGH
CrO2-HIGH
METAL-HIGH
26
24
22
18
16
14
12
10
8
6
4
2
0
–2
–4
20
50
100
200
500
1k
2k
5k
10k
20k
50k
Frequency (Hz)
B type encode characteristics
10
–40dB
VCC=8V
0dB=Dolby Level
=–10dBm
8
Encode boost (dB)
Output response (dB)
20
–30dB
6
4
–20dB
2
–10dB
0dB
0
20
50
100
200
1k
500
Frequency (Hz)
2k
—20—
5k
10k
20k
PB OUT
0.015µ
100k
+
M
4.7µ
4.7µ
50
47µ 180
+
2.2k
+
60
PB FB2
PB IN
Playback equalizer frequency response
PB FB1
CXA1897Q
CXA1897Q
Output level vs. MUTE voltage
VCC=8V
0dB=–10dBm
RL=2.7kΩ
MODE : NORM-NORM
(Tape) (Speed)
100Hz
1kHz
10kHz
0
–10
–20
Output level (dB)
1.0
–30
–40
–50
–60
–70
VCC=8V
MODE : NORM-NORM
(Tape) (Speed)
0dB=1kHz, +8dB
f=1kHz
–80
0.1
–90
–10
–5
0
5
10
Output level (dB)
15
0.0 1.0 2.0 3.0 4.0 5.0 6.0
REC MUTE pin voltage (V)
1.0
VCC=8V
Encode Mode, RL=10kΩ
0dB=Dolby Level
100Hz
1kHz
10kHz
0.1
0.01
B type total harmonic distortion
Total harmonic distortion (%)
NR off total harmonic distortion
Total harmonic distortion (%)
Total harmonic distortion (%)
Recording equalizer total harmonic distortion
1.0
VCC=8V
Encode Mode, RL=10kΩ
0dB=Dolby Level
100Hz
1kHz
10kHz
0.1
0.01
–10
–5
0
10 15
5
Output level (dB)
–10
—21—
–5
0
10 15
5
Output level (dB)
CXA1897Q
Package Outline
Unit : mm
48PIN QFP (PLASTIC)
15.3 ± 0.4
+ 0.1
0.15 – 0.05
+ 0.4
12.0 – 0.1
0.15
36
25
24
48
13
13.5
37
12
0.8
+ 0.15
0.3 – 0.1
0.24
M
0.9 ± 0.2
1
+ 0.2
0.1 – 0.1
+ 0.35
2.2 – 0.15
PACKAGE STRUCTURE
SONY CODE
QFP-48P-L04
EIAJ CODE
QFP048-P-1212
JEDEC CODE
PACKAGE MATERIAL
EPOXY RESIN
LEAD TREATMENT
SOLDER / PALLADIUM
PLATING
LEAD MATERIAL
42/COPPER ALLOY
PACKAGE MASS
0.7g
NOTE : PALLADIUM PLATING
This product uses S-PdPPF (Sony Spec.-Palladium Pre-Plated Lead Frame).
—22—