CXA1597M/P
Recording Equalizer Amplifier for Stereo Cassette Decks
Description
The CXA1597M/P is a bipolar IC developed for
recording equalizer amplifier in analog cassette
decks. It is suited specifically for double cassette
decks. Incorporating the filter circuit greatly reduces
the external parts.
Features
• Built-in filter required for recording equalizer
amplifiers
• Inductor (coil) is unnecessary
• Low frequency boost is possible with an external
capacitor
• Built-in recording mute function
(requiring only an external time constant circuit to
implement soft mute)
• Fade in/out DC controllable
• NORM/CrO2/METAL tape mode switching function
• NORM/HIGH tape speed recording switching
function
• DC controllable for recording level calibration
(approximately ±6dB variable)
• DC controllable for high frequency equalizer
amplifier gain (approximately ±4dB variable)
• Built-in 2 channels
• Small package
Applications
Recording equalizer amplifier for stereo analog
cassette decks (Supports ALPS ELECTRIC CO.,
LTD. HADKH55-series heads)
CXA1597M
16 pin SOP (Plastic)
CXA1597P
16 pin DIP (Plastic)
Structure
Bipolar silicon monolithic IC
Absolute Maximum Ratings
• Supply voltage
VCC
17
V
• Operating temperature Topr
–20 to +75 °C
• Storage temperature Tstg
–65 to +150 °C
• Allowable power dissipation
PD (CXA1597M) 500
mW
(CXA1597P) 900
mW
Operating Conditions
Supply voltage Dual power supplies (VCC – VEE)
±5.0 to 8.0 V
Single power supply (VCC)
10.0 to 16.0 V
Gp CAL
REC MUTE
REC CAL
REC IN2
IREF
BOOST2
VCC
REC OUT2
Block Diagram and Pin Configuration
16
15
14
13
12
11
10
9
BIAS
CONTROL
REC EQ 2
CXA1597M/P
REC EQ 1
TAPE EQ
DGND
REC IN1
5
6
7
8
REC OUT1
4
VEE
3
BOOST1
2
GND
1
SPEED
VG
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–
E95127-ST
CXA1597M/P
Pin Description
Pin
No.
Symbol
(Ta = 25°C, VCC = 7.0V, VEE = –7.0V, DVCC = 5.0V)
Typical pin voltage
DC
AC
I/O
Z (in)
Equivalent circuit
Description
10k
1
SPEED
—
—
I
—
1
DGND
2
TAPE EQ
2.5V
—
I
—
50k
5k
2
5k
DGND
3
DGND
0.0V
—
I
—
Tape speed
switching pin.
∗ Normal/Double
speed
switching.
High = Double
speed
Low = Normal
speed
Tape equalizer
amplifier switching
∗ (NORM/CrO2/
METAL
switching) pin.
High = REC EQ
METAL
Medium = REC
EQ CrO2
Low = REC EQ
NORM
Connect to GND.
GND
50k
4
13
REC IN1
REC IN2
0.0V
–18dBv
I
Recording
equalizer amplifier
input pin.
4
50kΩ
13
30k
5
GND (VG)
0.0V
—
I
GND
5
15kΩ
30k
–2–
Connect to GND
for positive/
negative dual
power supplies.
Vcc/2 (center
potential) for a
single power
supply. (Connect
a capacitor of
10µF or more)
CXA1597M/P
Pin
No.
Symbol
Typical pin voltage
DC
AC
I/O
Z (in)
Equivalent circuit
280
6
11
BOOST1
BOOST2
4.8k 5.5k
0.0V
—
I
9.5kΩ
34k
11
GND
7
VEE
8
9
REC OUT1
REC OUT2
–7.0V
—
I
–3dBv
O
—
50kΩ
50k
8
9
10
VCC
7.0V
—
I
200
12
IREF
—
O
Recording
equalizer amplifier
output pin.
—
Positive power
supply connection
pin.
—
Reference current
setting pin for
monolithic filter.
∗ The reference
current can be
set by attaching
a resistor
between this pin
and the VEE pin.
200
VEE
+ 1.2V
280
Connection pin of
an external
capacitor for low
frequency boost.
∗ When low
frequency boost
is unnecessary,
connect to GND
for positive/
negative dual
power supplies;
connect a
capacitor (3.3µF
or more) for a
single power
supply.
Connect to the
negative power
supply for
positive/negative
dual power
supplies.
Connect to GND
for a single power
supply.
200
0.0V
35.5k
6
Description
12
6k
–3–
CXA1597M/P
Pin
No.
Symbol
Typical pin voltage
DC
AC
I/O
Z (in)
Equivalent circuit
Description
54k
14
REC CAL
2.5V
—
I
54k
2.5V
14
54k
DGND
30k
15
REC MUTE
—
—
I
—
2.5V
15
54k
DGND
16
Gp CAL
2.5V
—
I
54kΩ
2.5V
16
54k
54k
DGND
–4–
∗ Recording level
calibration pin.
High =
Recording level
gain increased
Low =
Recording level
gain reduced
∗ Leave this pin
open when not
using the
recording level
calibration
function.
Recording mute
ON/OFF selection
pin.
∗ Recording mute
is controlled
with DC
voltages of 0 to
5V.
High =
Recording mute
OFF
Low =
Recording mute
ON
∗ Soft mute and
fader can be
switched over
by changing the
time constant of
the external
time constant
circuit.
High frequency
calibration pin.
∗ Controlled with
DC voltages of
0 to 5V
High = High
frequency level
gain increased
Low = High
frequency level
gain reduced
∗ Leave this pin
open when not
using the high
frequency
calibration
function.
CXA1597M/P
Electrical Characteristics
Item
(Ta = 25°C, VCC = 7.0V, VEE = –7.0V)
Conditions
Min.
Typ.
Max. Unit
8.0
12.0
16.0
mA
Operating voltage range 1 (positive/
negative dual power supplies)
±5.0
±7.0
±8.0
V
Operating voltage range 2
(single power supply)
10.0
14.0
16.0
V
Recording equalizer amplifier
Entire LSI
Current consumption (ICC)
Recording equalizer amplifier
Recording reference output level
NORM-NORM mode
Recording equalizer amplifier reference output
level (315Hz) (This output level is the tape
reference 0dB which generates magnetic flux of
250nWb/m)
All of the recording equalizer amplifier blocks use
this level as their reference level.
Recording equalizer amplifier
Recording reference input level
NORM-NORM mode
Input level when the reference output level is
315Hz, –3.0dBv
(For measurement, input a 315Hz, –18.5dBv
signal to the REC IN pins (Pins 4 and 13) and
then measure the output level.)
NORM-NORM mode
REC-EQ frequency response 1
(3kHz, –20dB)
NORM-tape, NORM-speed mode
Input a 3kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
–1.9
–0.4
1.1
dB
NORM-NORM mode
REC-EQ frequency response 2
(8kHz, –20dB)
NORM-tape, NORM-speed mode
Input a 8kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
2.5
4.5
6.5
dB
NORM-NORM mode
REC-EQ frequency response 3
(12kHz, –20dB)
NORM-tape, NORM-speed mode
Input a 12kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
7.3
10.3
13.3
dB
CrO2-NORM mode
REC-EQ frequency response 1
(3kHz, –20dB)
CrO2-tape, NORM-speed mode
Input a 3kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
2.9
4.4
5.9
dB
CrO2-NORM mode
REC-EQ frequency response 2
(8kHz, –20dB)
CrO2-tape, NORM-speed mode
Input a 8kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
7.1
9.1
11.1
dB
CrO2-NORM mode
REC-EQ frequency response 3
(12kHz, –20dB)
CrO2-tape, NORM-speed mode
Input a 12kHz signal (–20dB level down) from the
reference to the REC IN pins and then measure the
relative deviation from NORM-NS, 315Hz mode.
11.3
14.3
17.3
dB
METAL-NORM mode
REC-EQ frequency response 1
(3kHz, –20dB)
METAL-tape, NORM-speed mode
Input a 3kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
3.9
5.4
6.9
dB
METAL-NORM mode
REC-EQ frequency response 2
(8kHz, –20dB)
METAL-tape, NORM-speed mode
Input a 8kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
7.1
9.1
11.1
dB
–5–
dBv
–3.0
–20.0 –18.5 –17.0 dBv
CXA1597M/P
Recording equalizer amplifier
Item
Conditions
Min.
Typ.
Max. Unit
METAL-NORM mode
REC-EQ frequency response 3
(12kHz, –20dB)
METAL-tape, NORM-speed mode
Input a 12kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
10.4
13.4
16.4
dB
NORM-HIGH mode
REC-EQ frequency response 1
(5kHz, –20dB)
NORM-tape, HIGH-speed mode
Input a 5kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
–1.3
0.2
1.7
dB
NORM-HIGH mode
REC-EQ frequency response 2
(15kHz, –20dB)
NORM-tape, HIGH-speed mode
Input a 15kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
4.0
6.5
9.0
dB
NORM-HIGH mode
REC-EQ frequency response 3
(20kHz, –20dB)
NORM-tape, HIGH-speed mode
Input a 20kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
7.4
10.9
14.4
dB
CrO2-HIGH mode
REC-EQ frequency response 1
(5kHz, –20dB)
CrO2-tape, HIGH-speed mode
Input a 5kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
3.9
5.4
6.9
dB
CrO2-HIGH mode
REC-EQ frequency response 2
(15kHz, –20dB)
CrO2-tape, HIGH-speed mode
Input a 15kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
8.6
11.1
13.6
dB
CrO2-HIGH mode
REC-EQ frequency response 3
(20kHz, –20dB)
CrO2-tape, HIGH-speed mode
Input a 20kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
11.4
14.9
18.4
dB
METAL-HIGH mode
REC-EQ frequency response 1
(5kHz, –20dB)
METAL-tape, HIGH-speed mode
Input a 5kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
5.9
7.4
8.9
dB
METAL-HIGH mode
REC-EQ frequency response 2
(15kHz, –20dB)
METAL-tape, HIGH-speed mode
Input a 15kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
9.5
12.0
14.5
dB
METAL-HIGH mode
REC-EQ frequency response 3
(20kHz, –20dB)
METAL-tape, HIGH-speed mode
Input a 20kHz signal (–20dB level down) to the
REC IN pins and then measure the relative
deviation from NORM-NS, 315Hz mode.
11.8
15.3
18.8
dB
NORM-NORM mode
REC-EQ signal handling
NORM-tape, NORM-speed mode, RL = 2.7kΩ
Input a 1kHz signal and set the output so that
THD (total harmonic distortion) is 1%. (Measure
the distortion of a +11dB level-up signal.)
11.0
12.0
—
dB
NORM-NORM mode
REC-EQ total harmonic distortion
(1kHz, 0.0dB, RL = 2.7kΩ)
NORM-tape, NORM-speed mode, RL = 2.7kΩ
Input a 1kHz, 0.0dB (reference input level)
signal and measure the distortion. (Measure the
distortion as THD + N.)
—
0.14
0.6
%
–6–
CXA1597M/P
Recording equalizer amplifier
Item
Conditions
Min.
Typ.
NORM-NORM mode
REC-EQ S/N ratio 1
("A"-WGT filter)
NORM-tape, NORM-speed mode, Rg = 5.1kΩ
With no signal, measure the noise using the "A"WGT filter. (The measured value is indicated as
the relative value compared to the reference
level.)
57
65
—
dB
NORM-NORM mode
Output DC offset voltage
(REC OUT pin)
NORM-tape, NORM-speed mode
With no signal, measure the DC offset voltage of
the REC OUT pin.
–500
0.0
500
mV
NORM-NORM mode
REC-EQ mute characteristics 1
(REC-MUTE = 0.5V)
NORM-tape, NORM-speed mode, REC-MUTE = 0.5V
Input a 1kHz signal (+12dB level up) and
measure the attenuation when REC MUTE is on.
(Use a 1kHz BPF.)
—
–91
–80
dB
NORM-NORM mode
REC-EQ mute characteristics 2
(REC-MUTE = 2.5V)
NORM-tape, NORM-speed mode, REC-MUTE = 2.5V
Input a 1kHz, 0.0dB (reference level) signal and
measure the attenuation characteristics curve of
the soft mute function. (when REC-MUTE = 2.5V)
–7.0
–5.5
–4.0
dB
4.1
6.1
8.1
dB
–8.9
–6.9
–4.9
dB
NORM-tape, NORM-speed mode, REC-CAL = 5.0V
NORM-NORM mode
Input a 315Hz signal (–20dB level down) and
REC-EQ REC-CAL characteristics 1 measure the amount of change compared to
(REC-CAL = 5.0V)
when the REC-CAL function is at the standard
setting.
NORM-tape, NORM-speed mode, Gp-CAL = 5.0V
Input a 8kHz signal (–20dB level down) and
measure the amount of change compared to
when the Gp-CAL function is at the standard
setting.
3.9
5.9
7.9
dB
NORM-NORM mode
REC-EQ Gp-CAL characteristics 2
(GP-CAL = 0.0V)
NORM-tape, NORM-speed mode, Gp-CAL = 0.0V
Input a 8kHz signal (–20dB level down) and
measure the amount of change compared to
when the Gp-CAL function is at the standard
setting.
–5.9
–3.9
–1.9
dB
Ternary
switching
NORM-NORM mode
REC-EQ Gp-CAL characteristics 1
(GP-CAL = 5.0V)
Binary
switching
Control circuit
NORM-tape, NORM-speed mode, REC-CAL = 0.0V
NORM-NORM mode
Input a 315Hz signal (–20dB level down) and
REC-EQ REC-CAL characteristics 2 measure the amount of change compared to
(REC-CAL = 0.0V)
when the REC-CAL function is at the standard
setting.
Max. Unit
Mode control
Control circuit high level
TAPE EQ control pin voltage
4.2
—
VCC
V
Mode control
Control circuit medium level
TAPE EQ control pin voltage
2.2
—
2.8
V
Mode control
Control circuit low level
TAPE EQ control pin voltage
0.0
—
0.5
V
Mode control
Control circuit high level
SPEED control pin voltage
3.5
—
VCC
V
Mode control
Control circuit low level
SPEED control pin voltage
0.0
—
0.5
V
–7–
GND
DC
Ammeter
Power
Supply
A
∗R1 2k
DC
Ammeter
Power
Supply
A
DC 5V
Supply
∗R6
2k
OFF
GP CAL
50k
METAL
120µs
SW3
SW4 METAL
NORM
METAL
SW2
SPEED
HIGH
ON
SW1
REC MUTE
4.0V
5.0V
70µs
∗R3 27k
0.5V
∗R5 18k
2.5V
∗R4
27k
C3
1µ
25V
SW5
R9
10k
16
∗R7
620
R10
10k
Audio SG
R8
10k
C2
1µ
25V
2
1
C4
10µ
15
OFF CAL ON/OFF
ON
C5
10µ
C6
10µ
14
3
SW7
SW6
13
12
4
SW9
∗R11
5.1k
C7
2.2µ
11
6
5
C9
10µ
∗R13
27k
CXA1597M/P
C8
2.2µ
∗R12
5.1k
SW8
GND (VG)
∗R2
18k
Gp CAL
SPEED
REC MUTE
TAPE EQ
REC IN2
REC IN1
REC CAL
DGND
IREF
∗C11 0.47µ
BOOST2
BOOST1
∗C10 0.47µ
–8–
C12
100µ
25V
8
7
C14
4.7µ
50V
9
10
VCC
C1
100µ
25V REC CAL
50k
VEE
C13 100µ
REC OUT1 REC OUT2
Electrical Characteristics Measurement Circuit
∗R16
2.7k
SW11
R14 10k
R18
100
R19 100
∗R17
2.7k
SW10
R15 10k
C15
4.7µ
50V
IN
Coupling Capacitor
2. Capacitor tolerance ∗:
∗:
DC Voltmeter
Oscilloscope
Distortion
Analyzer
AC Voltmeter
Noise Filter
Note 1. Resistor tolerance
1ch
SW13
2ch
OUT
SW14
Filter
1ch
SW12
2ch
1kHz BPF
DIN Audio
"A" WTG
±5%
±1%
±5%
±2%
±10%
SW17
SW16
SW15
CXA1597M/P
TAPE EQ
(METAL/CrO2/NORMAL)
Tape Speed
(NORM/HIGH)
Gp CAL
(DC control)
R5
5.6k
2
1
RV1
10k
C1
3.3µ
50V
R4
5.6k
GND
C3
0.47µ
35V
GND
6
5
4
7
C5
100µ
25V
8
C7
3.3µ
50V
C8
3.3µ
50V
GND
GND
C9
150p
R6
12k
R7
12k
C10
150p
GND
L1
27mH
C11
75p
C12
75p
L2
27mH
REC OUT1
(to HEAD)
REC OUT2
(to HEAD)
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.
GND R1
10k
3
REC IN1
CXA1597M/P
9
10
11
12
13
C6
100µ
25V
14
C4
0.47µ
35V
GND
15
R3
27k
VEE
16
C2
3.3µ
50V
RV2
10k
GND (VG)
REC Mute
(Soft Mute/Fader)
R2
10k
Gp CAL
SPEED
REC MUTE
TAPE EQ
REC CAL
DGND
REC IN2
BOOST1
REC CAL
(DC control)
LINE IN2
LINE IN1
IREF
VEE
BOOST2
VCC
VEE
VCC
REC OUT1
REC OUT2
VEE
–9–
GND
Application Circuit (Positive/Negative Dual Power Supplies)
CXA1597M/P
CXA1597M/P
Description of Operation
1. Recording equalizer amplifier
The primary features of the CXA1597 recording equalizer amplifier are that by taking full advantage of
monolithic filter technology, an LC resonance circuit consisting of a coil and capacitor normally required for
high frequency compensation is dispensed with and medium and low-frequency sensitivity compensation is
performed with its internal filter alone.
This IC has the circuit configuration shown in Fig. 1 to provide the optimum frequency response required for
recording equalizer amplifiers.
GND
C1
0.47µ
OP2
R3
35k
R7
34k
Bias
OSC
GND
IfM
C2
200p
Gm2
×1
R11
–7dBv 40k
VCC
VEE
GND (VG)
R1 27k
BIAS
IREF
R10
8k
–6dBv
DGND
GND
R6
20k
R2
5k
×1
If/Q
REC MUTE
SPEED
to Control IC
–6dBv
×1
C3
100p
CONTROL
GND
C6
150p
GND
IfQ
Gm4
GND
TAPE EQ
REC HEAD
C4
100p
GND
R5
20k
L1
27mH
GND
R13
50k
R9
24k
Gm3
OP3
R14
12k
C5
3.3µ
IGL
VGS
GND
IGH
VGS
GND VEE GND VEE VCC
VGS
REC OUT
–3dBv
OP4
Gm5
VGS
C7
75p
GND
+6dBv
R1
50k
BOOST
R8
4.8k
–7dBv
R4
0dBv 5.5k
VGS
REC IN
–18.5dBv
DVCC
IGP
REC CAL
CALIBRATION
Gp CAL
R15
50k
R16
50k
GND
Fig. 1. CXA1597 functional circuit block diagram
The symbols (Gm2, Gm3, Gm4, Gm5) shown in Fig. 1 denote "voltage → current converter circuits" and
"multiplier circuits."
The "voltage → current converter circuits" convert the voltage between the positive and negative input pins into
current by using the IC's internal resistance. The "multiplier circuits" multiply the current generated by the
"voltage → current converter circuits" with a coefficient.
The recording equalizer amplifier requires the six parameters shown in Fig. 2 (GL, GH, GP, fM, fP, and Q) to
implement its frequency response. These parameters are controlled by each control current shown in Fig. 1
(IGL, IGH, IGP, IfM, If/Q, and IfQ).
Therefore, the CXA1597 reduces fluctuations caused by the temperature characteristics and unevenness of its
internal resistance by using currents which are independent of the internal resistance (currents which depend
on external resistance) and those which are dependent on the internal resistance.
This IC uses currents dependent on the internal resistance where equalizer amplifier gain is determined and
currents dependent on external resistance where the filter time constant is determined. This is because the
generatrix of the coefficient for the "multiplier circuits" is generated in the IC so that it depends on the internal
resistance. Consequently, the gain relationship of GL, GH and GP is such that because the current obtained by
the "voltage → current converter circuits" is converted into voltage by the I-V amplifier in the final stage of Fig.
1, the control currents are controlled by currents dependent on the internal resistance. In this way, the
coefficients for conversion [voltage → current → voltage] all become ratios to the internal resistance, so that
the fluctuations of temperature characteristics and unevenness are reduced.
– 10 –
CXA1597M/P
Also, the relationship of time constants fM, fP and Q is configured by the product of the current obtained with
the "voltage → current converter circuits" and the IC's internal capacitance connected to the output of each
"multiplier circuit". By using the currents determined by the CXA1597 external resistance which are not
dependent on the internal resistance for control, the coefficients for voltage → current conversion become
certain ratios to the internal resistance; therefore, the frequency response does not depend on the internal
resistance.
GP
Low frequency boost
Gain [dB]
Q
GH
GL
fM
fP
Frequency [Hz]
Fig. 2. Conceptual diagram of CXA1597 frequency response
2. Low frequency boost
The CXA1597 implements low frequency boost simply by attaching an external capacitor. As shown in Fig. 1,
this IC contains a resistance-based attenuation circuit after the input amplifier, with one of the resistors
connected to the BOOST pins (Pins 6 and 11). When a capacitor is connected to these BOOST pins (Pins 6
and 11), the following transfer function is obtained.
GBOOST (s) =
s • C1 • R7 • R8 + R7
s • C1 • (R4 • R7 + R7 • R8 + R8 • R4) + (R4 + R7)
(s = jω)
From the above, items f1, f2, A1, and A2 in Fig. 3 are transformed into the following:
f1 =
R4 + R7
2π • C1 • (R4 • R7 + R7 • R8 + R8 • R4)
f2 =
1
2π • C1 • R8
A1 =
R7
R4 + R7
A2 =
R7 • R8
=
R4 • R7 + R7 • R8 + R8 • R4
1
=
2π • C1 •
R7 • R8
R7 + R8
R4 +
R7 • R8
R7 + R8
– 11 –
(
R4 • R7 + R8
R4 + R7
)
CXA1597M/P
Here, R4 = 5.5kΩ, R7 = 34kΩ, and R8 = 4.8kΩ. Therefore, A1 and A2 take on the following values.
A1 = 0.861 (times) = –1.30 (dB); A2 = 0.433 (times) = –7.26 (dB)
The difference between A1 and A2 is approximately 6 dB, so that 6 dB boost can be applied for low frequency
boost. The boost frequency response can be freely set with the value of the external C1 capacitor.
A1
Gain [dB]
6dB
A2
oct
f1
f2
Frequency [Hz]
Fig. 3. CXA1597 low frequency boost frequency response
3. Recording mute function
The CXA1597 recording mute function is implemented by using a built-in recording mute circuit which varies
the recording equalizer amplifier gain according to the magnitude of the DC voltage applied to the REC
MUTE pin (Pin 15) just like an electronic volume control. For this reason, any desired soft mute (gradual
signal attenuation without distortion) or fader (fade in/out) can be freely set depending on momentary
changes in the DC voltage applied to the REC MUTE pin (Pin 15).
The CXA1597 recording mute circuit operation is such that the reference voltage source used to generate the
control currents (IGL, IGH, and IGP) to control each gain (GL, GH, and GP) shown in Fig. 1 is varied by the
voltage input to the REC MUTE pin (Pin 15), so that the recording signal is attenuated while maintaining the
respective gain ratios. Eventually, when the recording signal is completely muted, only the I-V amplifier in the
final stage is connected to the output pin (REC OUT). Therefore, the noise of the monolithic filter consisting of
each "voltage → current converter circuit" and "multiplier circuit" is attenuated simultaneously with the
recording signal. At this point in time, the I-V amplifier in the final stage is functioning almost as a buffer,
providing a significant amount of mute. Fig. 4 illustrates the recording mute waveforms.
Fig. 4. Recording mute waveform
– 12 –
CXA1597M/P
4. Recording level calibration function
The CXA1597 allows the recording level to be finely adjusted with a DC voltage. The recording equalizer
amplifier gain can be varied by approximately ±6dB simply by applying DC voltage to the REC CAL pin (Pin
14). Circuit operation for this function is such that each gain (GL, GH, and GP) is varied relative to the
reference voltage source which controls currents (IGL, IGH, and IGP) by varying its voltage as in the case of
the recording mute circuit.
The input resistance of the REC CAL pin (Pin 14) is 54kΩ as described in the Pin Description, which is
equivalent to the internal resistance. This means the voltage converted into current by the internal resistance
is the difference between the DC voltage applied to the REC CAL pin (Pin 14) and the internal reference
voltage (2.5V), so that all coefficients become ratios to the internal resistance. Recording level can be finely
adjusted independent of the temperature characteristics and unevenness inherent in the IC.
This recording calibration function performs in all modes (NORM/CrO2/Metal tape, NORM/HIGH speeds, as
well as the recording mute mode).
When not using the recording level calibration function, simply leave the REC CAL pin (Pin 14) open, and the
voltage on the REC CAL pin (Pin 14) is matched to the internal reference voltage (2.5V), with the recording
level set for the standard output gain.
5. High frequency equalizer amplifier calibration function
In addition to the recording level calibration function, the CXA1597 allows high frequency equalizer amplifier
characteristics to be controlled with DC voltage. By simply applying DC voltage to the GP CAL pin (Pin 16) as
in the case of the recording level calibration function, the recording equalizer amplifier gain (only the GP gain)
can be varied by approximately ±4dB. This function also relatively varies the GP gain when the recording
level calibration function is activated. Circuit operation for this function is such that the voltage applied to the
pin is converted into current by the internal resistance as in the case of recording level calibration, and that
the "multiplier circuits" provide a coefficient to the control current according to the value of the GP gain
control current (IGP) for the mode currently set.
Therefore, the calibration of high frequency equalizer amplifier characteristics is independent of the
temperature characteristics and unevenness inherent in the IC, as in the case of recording level calibration.
This function, too, operates in all modes.
When not using the high frequency equalizer amplifier calibration function, simply leave the GP CAL pin (Pin
16) open, and the high frequency equalizer amplifier characteristics are set for standard output gain.
Fig. 5 schematically shows the recording level/high frequency equalizer amplifier calibration functions.
GP CAL
Gain [dB]
REC CAL
REC CAL
REC CAL
fM
fP
Frequency [Hz]
Fig. 5. Conceptual diagram of recording level/high frequency equalizer amplifier calibration functions
The noise level of the recording equalizer amplifier is relatively changed by varying its frequency characteristics.
– 13 –
CXA1597M/P
6. Temperature characteristics and accuracy of the recording equalizer amplifier
The temperature characteristics of the built-in monolithic filter and the filter cut-off frequency depend on the
27kΩ external resistance connected to the IREF pin (Pin 12). For low frequency boost, however, the cut-off
frequency becomes uneven depending on the temperature characteristics or unevenness of the internal
resistance since its time constant is configured by the product of an external capacitor and the internal
resistance.
Also, the recording equalizer frequency response depends on unevenness in the absolute, as well as relative
values of the internal capacitance. Furthermore, the high frequency response indicates a high element
sensitivity at the filter because the band-pass filter Q is high. Compared to low frequency, although the
unevenness inherent in the IC is more likely to occur, this occurs relatively, and not individually for channels 1
and 2.
– 14 –
CXA1597M/P
Notes on Operation
1. Power supply
The CXA1597 is designed basically for positive/negative dual power supplies, and can also operate with a
single power supply. Connect the power supplies for each case as shown below:
VCC (Pin 10)
VEE (Pin 7)
GND (Pin 5) DGND (Pin 3)
Positive/negative dual
power supplies
Positive power supply
Negative power supply
GND
GND
Single power supply
Power supply
GND
∗
GND
∗ For a single power supply, connect a decoupling capacitor (10µF or more) to the GND (VG) pin (Pin 5).
The ripple rejection ratio depends on the capacitance of this capacitor.
2. Operation mode control (NORM/CrO2/METAL tape, NORM/HIGH speed)
The CXA1597 incorporates an electronic switch and its operation is controlled by the DC voltage applied to
the two mode control pins - TAPE EQ pin (Pin 3) and SPEED pin (Pin 1).
The mode control voltages are as follows
3-state
2-state
Control voltage
Min.
Max.
High level
4.2
VCC
Medium level
2.2
2.8
Low level
0.0
0.5
High level
3.5
VCC
Low level
0.0
0.5
The voltages in the table to the left are the
values relative to DGND.
Operation mode control table
Pin voltage
Pin No.
Pin name
1
SPEED
HIGH SPEED
2
TAPE EQ
METAL TAPE
M
H
CrO2 TAPE
L
Remarks
NORMAL SPEED
2-state
NORMAL TAPE
3-state
Note: Pin voltage = Medium when the 3-state input pin is open.
If the switching click noise presents a problem, add time constant circuits of 0.1 to 1s to the mode control
pins. Since the mode control circuit has a linear region of approximately ±300mV, this time constant circuit
may effectively reduce the switching click noise.
– 15 –
CXA1597M/P
3. Recording mute function (soft mute, fade in/out)
As described in Description of Operation, the CXA1597 recording mute function is implemented by using a
built-in recording mute circuit which varies the recording equalizer amplifier gain according to the magnitude
of the DC voltage applied to the REC MUTE pin (Pin 15) just like an electronic volume control. Consequently,
the muting time can be varied according to momentary changes of the DC voltage applied to the REC MUTE
pin (Pin 15) and, furthermore, the recording signal can be gradually attenuated without causing distortion.
The table below shows the relationship between the DC voltage applied to the REC MUTE pin (Pin 15) and
the attenuation.
Control voltage
Recording mute ON
Attenuation –6.6dB
Recording mute OFF
Positive/negative dual power supplies
DGND to 0.5V
2.5V
4.0V to VCC
Single power supply
DGND to 0.5V
2.5V
4.0V to VCC
∗ Referenced to the DGND pin (Pin 3).
4. Low frequency boost (low frequency compensation)
The CXA1597 low frequency boost function can be implemented simply by connecting a capacitor to the
BOOST pins (Pins 6 and 11) as described in Description of Operation. Although the boost is fixed to 6dB, the
time constant which determines the cut-off frequency can be set to any desired value depending on the
capacitance of the external capacitor. The pole (f1) and zero (f2) shown in Fig. 3. Low frequency boost
frequency response can be expressed, with the external capacitor assumed to be CB, as follows:
f1 =
1
2π • CB • (9.53kΩ)
(Hz), f2 =
1
2π • CB • (4.8kΩ)
(Hz)
Based on the above equation, determine the best low frequency response.
However, the resistance which determines the time constant along with the external capacitor is the internal
resistance, so that the cut-off frequency tends to fluctuate depending on the unevenness and temperature
characteristics inherent in the IC. Note that the unevenness and the temperature characteristics of the
internal resistance that determines the low frequency boost frequency response are approximately ±20% and
+2500 ppm/°C, respectively.
When not using low frequency boost, follow the procedure described below.
a) For positive/negative dual power supplies
Connect the BOOST pins (Pins 6 and 11) to GND.
b) For single power supply
Connect a fairly large capacitor (3.3µF or more) to the BOOST pins (Pins 6 and 11) or simply leave the
BOOST pins open. If the BOOST pins are left open, note that the output level increases by 6dB, so the
input reference should be set 6dB down. The CXA1597 is basically designed for positive/negative dual
power supplies and the BOOST pins cannot be easily connected to GND as in the case of
positive/negative dual power supplies.
– 16 –
CXA1597M/P
5. Recording level calibration
The CXA1597 allows the recording level to be finely adjusted with a DC voltage as described in Description
of Operation. Therefore, the recording level can be varied by approximately ±6dB simply by applying DC
voltages of 0 to 5V (for positive/negative dual power supplies) to the REC CAL pin (Pin 14).
The table below shows the input range regulation of control voltages with the power supplies used.∗1, ∗2
Up
Typ.
Down
Positive/negative dual power supplies
2.5V to VCC
2.5V
DGND to 2.5V
Single power supply
2.5V to VCC
2.5V
DGND to 2.5V
∗1 Although the above range of voltages can be input to the control pin, the controllable input voltage range
is as follows:
2.5V < Vup ≤ 5.0V
DGND ≤ Vdown < 2.5V
∗2 Control voltages for this IC are referenced to the DGND pin (Pin 3).
Also note that when not using this recording calibration function, simply leave the REC CAL pin (Pin 14)
open, so that the voltage on the REC CAL pin is matched to the internal reference voltage (2.5V), with
the recording level set for the standard gain.
6. High frequency calibration
The CXA1597 allows the high frequency equalizer amplifier characteristics to be finely adjusted with a DC
voltage as described in Description of Operation. Therefore, the recording level in high frequencies (peak)
can be varied by approximately ±4dB simply by applying DC voltages of 0 to 5V (for positive/negative dual
power supplies) to the GP CAL pin (Pin 16).
The table below shows the input range regulation of control voltages with the power supplies used. ∗3, ∗4
Up
Typ.
Down
Positive/negative dual power supplies
2.5V to VCC
2.5V
DGND to 2.5V
Single power supply
2.5V to VCC
2.5V
DGND to 2.5V
∗3 Although the above range of voltages can be input to the control pin, the controllable input voltage range
is as follows:
2.5V < Vup ≤ 5.0V
DGND ≤ Vdown < 2.5V
∗4 Control voltages for this IC are referenced to the DGND pin (Pin 3).
Also note that when not using this high frequency calibration function, simply leave the GP CAL pin (Pin
16) open, so that the voltage on the GP CAL pin is matched to the internal reference voltage (2.5V), with
the high frequency equalizer amplifier characteristics set for the standard gain.
7. Monolithic filter (the resistance connected to the IREF pin)
To increase the accuracy of the frequency response of its internal monolithic filter, the CXA1597 entrusts the
control current that determines the filter time constant to an external resistance. Specifically, this resistance
is the 27kΩ external resistor connected to the IREF pin (Pin 12). This means that the accuracy of the
recording equalizer amplifier frequency response is determined by the resistance connected to the IREF pin.
Therefore, the resistor used for this purpose must be free of unevenness and have excellent temperature
characteristics (e.g., a metallic film resistor).
Also note that the recording equalizer amplifier frequency response can be shifted as desired by altering the
value of the resistance connected to the IREF pin. For example, when the resistance value is reduced, the
frequency response is shifted to the high-frequency side, and when the resistance value is increased, the
frequency response is shifted to the low-frequency side.
– 17 –
CXA1597M/P
Example of Representative Characteristics
Frequency response (NORMAL speed)
Output response [dB]
30.0
20.0
VCC, VEE = ±7.0V
0dB = NORM-NORM, 315H, –23dBv (–20dB)
(Tape) (Speed)
NORM -NORM
CrO2 -NORM
METAL-NORM
10.0
0.0
–10.0
10
100
1k
10k
100k
Frequency [Hz]
Frequency response (HIGH speed)
Output response [dB]
30.0
20.0
VCC, VEE = ±7.0V
0dB = NORM-NORM, 315H, –23dBv (–20dB)
(Tape) (Speed)
NORM -HIGH
CrO2 -HIGH
METAL-HIGH
10.0
0.0
–10.0
10
100
1k
10k
Frequency [Hz]
Load characteristics
14
Maximum output level [dB]
12
10
8
VCC, VEE = ±7.0V
MODE: NORM-NORM
(Tape) (Speed)
0dB = –3dBv (REC OUT pin)
THD + N = 1%
315Hz
1kHz
6
4
2
0
100
1k
RL – Load resistance [Ω]
– 18 –
10k
100k
CXA1597M/P
Output level vs. Mute voltage
Total harmonic distortion
1.0
100
VCC, VEE = ±7.0V
0dB = –3dBv, RL = 2.7k
MODE: NORM-NORM
(Tape) (Speed)
315Hz
1kHz
3kHz
6.3kHz
10kHz
15kHz
80
Output level [%]
T. H. D + N [%]
10
60
40
VCC, VEE = ±7.0V
MODE: NORM-NORM
(Tape) (Speed)
100% = 1kHz, + 12dB
(at 315Hz, –3dBv)
f = 1kHz
20
0.1
–10
0
10
20
0
Output level [dB]
–1.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
REC MUTE pin voltage [V]
Output level vs. Mute voltage
Output level vs. Mute voltage
0
0
–20
–40
Output level [dB]
Output level [dB]
–20
–60
VCC, VEE = ±7.0V
MODE: NORM-NORM
(Tape) (Speed)
0dB = 1kHz, + 12dB
(at 315Hz, –3dBv)
f = 1kHz
–80
–40
–60
VCC, VEE = ±7.0V
MODE: NORM-NORM
(Tape) (Speed)
0dB = 1kHz, + 12dB
(at 315Hz, –3dBv)
f = 1kHz
–100
0.0
1.0
2.0
3.0
4.0
5.0
6.0
REC MUTE pin voltage [V]
–80
0.5
1.0
5.0
REC MUTE pin voltage [V]
– 19 –
CXA1597M/P
Output level vs. REC CAL voltage
Output level [dB]
10
0
VCC, VEE = ±7.0V
MODE: NORM-NORM Gp CAL = Open
(Tape) (Speed)
0dB = REC CAL pin and Gp CAL pin Open
–20dB (at 315Hz, –3dBv)
315Hz
3kHz
8kHz
12kHz
–10
–2.0 –1.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
REC CAL pin voltage [V]
Output level vs. Gp CAL voltage
Output level [dB]
5
0
VCC, VEE = +7.0V
MODE: NORM-NORM REC CAL = Open
(Tape) (Speed)
0dB = Gp CAL pin and REC CAL pin Open
–20dB (at 315Hz, –3dBv)
315Hz
3kHz
8kHz
12kHz
–5
–2.0 –1.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
Gp CAL pin voltage [V]
REC CAL and Gp CAL frequency response
Output response [dB]
40.0
VCC, VEE = ±7.0V
0dB = NORM-NORM, 315Hz, –23dBv (–20dB)
REC CAL & Gp CAL Open
30.0
(Tape) (Speed)
Gp CAL = 5.0V
Gp CAL = 2.5V
Gp CAL = 0.0V
20.0
10.0
REC CAL = 5.0V
REC CAL = 2.5V
0.0
REC CAL = 0.0V
–10.0
10
100
1k
Frequency [Hz]
– 20 –
10k
100k
CXA1597M/P
Supply voltage vs. Current consumption
ICC – Current consumption [mA]
13
12
11
10
5
6
7
VCC – Supply voltage [V]
– 21 –
8
CXA1597M/P
Package Outline
Unit: mm
CXA1597M
16PIN SOP (PLASTIC) 300mil
+ 0.4
9.9 – 0.1
+ 0.4
1.85 – 0.15
16
9
6.9
8
+ 0.1
0.2 – 0.05
1.27
0.45 ± 0.1
0.5 ± 0.2
1
+ 0.2
0.1 – 0.05
7.9 ± 0.4
+ 0.3
5.3 – 0.1
0.15
± 0.12 M
PACKAGE STRUCTURE
PACKAGE MATERIAL
SONY CODE
SOP-16P-L01
EIAJ CODE
∗SOP016-P-0300-A
EPOXY RESIN
LEAD TREATMENT
SOLDER PLATING
LEAD MATERIAL
COPPER ALLOY
PACKAGE WEIGHT
0.2g
JEDEC CODE
CXA1597P
16
+ 0.3
6.4 – 0.1
+ 0.4
19.2 – 0.1
+ 0.1
0.05
0.25 –
16PIN DIP (PLASTIC) 300mil
7.62
9
1
0° to 15°
8
0.5 MIN
3.0 MIN
+ 0.4
3.7 – 0.1
2.54
0.5 ± 0.1
1.2 ± 0.15
PACKAGE STRUCTURE
PACKAGE MATERIAL
EPOXY RESIN
SONY CODE
DIP-16P-01
LEAD TREATMENT
SOLDER PLATING
EIAJ CODE
∗DIP016-P-0300-A
LEAD MATERIAL
COPPER
JEDEC CODE
Similar to MO-001-AE
PACKAGE WEIGHT
1.0 g
– 22 –