Preamplifier for Compact Cassette Recorder
Recording-only Use
Overview
The LA3242 is a preamp IC for compact cassette recorder
recording-only use. The distinctive feature of the LA3242 is
that it contains mechanical switches which have been so far
connected externally as peripheral parts.
Features
.
On-chip electronic select switches permitting selection of
normal/higher speed recording and metal(chrome)/normal
tape recording mode by using the dedicated control pins.
.
Two ALC output pins making it easy to make up a Dolby
recording system.
.
The control voltage from a microcomputer, etc. can be used
to turn ON/OFF the ALC and to set the ALC control voltage
to the initial value.
.
On-chip microphone amplifier making it easy to provide
microphone mixing.
.
Wide operating voltage range (V
CC
= 4.5 to 14.0 V).
.
Can be used in conjunction with playback-only preamp
LA3246 to make up a double-cassette dubbing system.
Functions
.
Recording preamplifier
2
.
Microphone amplifier
1
.
ALC output
2
.
Electronic switch
6
Package Dimensions
unit : mm
3067-DIP24S
[LA3242]
SANYO : DIP24S
Specifications
Maximum Ratings
at Ta = 25C
Parameter
Symbol
Conditions
Ratings
Unit
Maximum supply voltage
V
CC
max
16
V
Allowable power dissipation
Pd max
720
mW
Operating temperature
Topr
20 to +75
C
Storage temperature
Tstg
40 to +125
C
Operating Conditions
at Ta = 25C
Parameter
Symbol
Conditions
Ratings
Unit
Recommended supply voltage
V
CC
6
V
Operating voltage range
V
CC
op
4.5 to 14.0
V
Ordering number: EN 2620C
Monolithic Linear IC
LA3242
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
D3097HA(II)/N257TA/7027TA,TS No.2620-1/12
Operating Characteristics
at Ta = 25C, V
CC
= 6.0 V, R
L
= 10 k
, f = 1 kHz, 0 dB = 0.775 V
Parameter
Symbol
Conditions
min
typ
max
Unit
Quiescent current
I
CCO
Me/Nor, Nor/High SW OFF
5
7.5
12
mA
Quiescent current
I
CCS
Me/Nor, Nor/High SW ON
12
16
20
mA
[REC Amp]
Voltage gain (Open)
VG
O
1
75
85
dB
Voltage gain (Closed)
VG1
V
O
= 0 dBm
42.5
44.5
46.0
dB
Total harmonic distortion
THD 1
V
O
= 0.4 V
0.1
0.7
%
Maximum output voltage
V
O
max
THD = 1%
0.7
1.0
V
Equivalent input noise
voltage
V
NI
1
Rg = 2.2 k
, B.P.F = 20 Hz to 20 kHz
1.1
1.7
V
Input resistance
R
I
1
40
50
60
k
Crosstalk
CT1
Between REC amps
50
60
dB
CT2
REC amp
Microphone amp
50
75
dB
Channel balance
V
BL
V
IN
= 50 dBm
0
2
dB
[Microphone Amp]
Voltage gain (Open)
VG
O
2
60
70
dB
Voltage gain (Closed)
VG2
V
O
= 0 dBm
23
25
27
dB
Total harmonic distortion
THD2
V
O
= 0.4 V
0.05
0.5
V
Maximum output voltage
V
O
max
THD = 1%
0.8
1.1
V
Equivalent input noise
voltage
V
NI
2
Rg = 2.2 k
, B.P.F = 20 Hz to 20 kHz
1.1
1.7
V
Input resistance
R
I
2
40
50
60
k
Crosstalk
CT3
Microphone amp
REC amp
45
60
dB
[ALC]
ALC range
ALC
W
Input range when output distortion becomes 1%
after ALC begins to the applied.
40
45
dB
ALC balance
ALC
B
Output difference between CH1 and CH2
0
2
dB
ALC distortion
ALC
THD
V
IN
= 40 dBm
0.15
0.8
%
ALC output voltage
ALC
VO
V
IN
= 40 dBm
0.33
0.42
0.53
V
Crosstalk
CT4
Between REC amps
45
60
dB
Crosstalk
CT5
REC amp
Microphone amp
50
70
dB
ALC ON-state voltage
ALCon
Voltage on pin 17
1.0
V
ALC OFF-state voltage
ALCoff
Voltage on pin 17
1.5
V
[Switch]
ON-state resistance
R
ON
30
70
DC feedback resistance
R
F
1
40
50
60
k
Allowable
power
dissipation,
Pd
max
m
W
Ambient temperature, Ta C
Pd max Ta
LA3242
No.2620-2/12
Equivalent Circuit Block Diagram
Equivalent Circuit
Top view
LA3242
No.2620-3/12
Sample Application Circuit
Note:
1.
The electronic select switching level is approximately (V
CC
0.9)/2.
2.
REC amplifier NF parameters Z1 through Z3 should be selected to accommodate the recording level and frequency response
that will be required in metal/normal tape and normal/higher speed modes.
3.
Z1 through Z3 may be configured with coil ``L'', capacitor ``C'', and resistor ``R''.
4.
When electronic control pins 9 and 16 are at the GND level, each electronic switch is turned ON.
5.
When ALC ON/OFF control pin 17 is at 1 V or less/1.5 V or greater, the ALC is turned ON/OFF, respectively (Ta = 25C).
6.
The ALC width depends on external resistor R
A
.
LA3242
No.2620-4/12
Test Circuit
Sample Printed Circuit Pattern (Cu-foiled area)
130
130 mm
2
Unit (resistance:
, capacitance: F)
LA3242
No.2620-5/12
IC usage Notes
(1) The base of a PNP transistor is connected to input pins 2 and 23.
When a voltage is applied to input pins 2 and 23 externally, connect a
capacitor to the input pins. The recommended value of capacitor C is
0.1 F to 10 F. DC voltage V
INDC
with input pins 2 and 23 open is
50 mV max (V
INDC
= 20 mV typ).
(2) Output waveform starting time (Refer to Data t
s
C
r
.)
When supply voltage V
CC
is switched ON, the amplifier output (pins 7 and 18) will rise. Output waveform ON time ts can be
varied by capacitor Cr connected to pin 12. The minimum value of Cr is 33 F. If the value of Cr is made less than 33 F, more
pop noise will occur and the ripple rejection will worsen at the time supply voltage V
CC
is switched ON. (ts = 0.7 s. typ at
Cr = 100 F)
(3) Electronic switch control circuit
The control circuit for control pins 9 and 16 is configured as
shown left.
Control level V
CONT
of the control circuit is given by:
V
CONT
= 1/2
(V
CC
0.9) [V]
(4) Relation between control voltage to turn ON/OFF electronic switch and supply voltage (Refer to Data V
CONT
V
CC
.)
The control level at electronic switch CONT pin 9 and 16 is fixed
by supply voltage V
CC
. The threshold region has a range of
approximately 1 V. The middle point of threshold region at a
given value of supply voltage V
CC
is represented by approximately
1/2
(V
CC
0.9) V.
The electronic switch can be turned ON/OFF by applying a
voltage of the middle point voltage
0.5 V or more/less,
respectively, to electronic switch CONT pins 9 and 16.
For the relation between supply voltage V
CC
and V
INDC
, refer to the V
CC
V
INDC
characteristic.
Rise waveform at pin 7 or 18
Control
pin
.
4 Amin
Electronic
SW ON
signal
Electronic SW OFF
Electronic SW ON
Threshold region (
.
1 V)
LA3242
No.2620-6/12
(5) ALC control pin and ON/OFF level
The ALC ON/OFF control circuit is configured as shown left.
When a voltage of (V
BE
1+V
BE
2) = 1.5 V or greater is applied to the
ALC CONT17, the potential on the ALC IN (pin 8) drops to GND
level. The ALC is turned OFF (ALC function release).
Threshold
region
REC amplifier output V
OAC
is controlled by the ALC CONT
voltage and the threshold region has a range of approximately 0.5 V.
The ALC CONT voltage is set to 1.0 V or less/1.5 V or greater to
turn ON/OFF the ALC, respectively.
(Refer to Data V
OAC
, V8, I
1
V
ALC CONT
.)
V
oltage
gain
(Open),
VG
O
d
B
V
oltage
gain
(Closed),
VG
d
B
Either Me/Nor or Nor/High On
Input frequency, f
IN
Hz
V
oltage
gain
(Open),
VG
O
d
B
V
oltage
gain
(Closed),
VG
d
B
Input frequency, f
IN
Hz
VG
O
, VG f
IN
VG
O
, VG f
IN
Quiescent
current,
I
CCO
m
A
Quiescent
current,
I
CCS
(Electronic
SW
ON)
m
A
Supply voltage, V
CC
V
V
oltage
gain,
VG
d
B
Supply voltage, V
CC
V
I
CCO
, I
CCS
V
CC
VG V
CC
LA3242
No.2620-7/12
Output
voltage,
V
O
V
T
otal
harmonic
distortion,
THD
%
Input voltage, V
IN
dBm
Crosstalk,
CT
d
B
Supply voltage, V
CC
V
V
O
, THD V
IN
CT V
CC
Maximum
output
voltage,
V
O
m
a
xV
Supply voltage, V
CC
V
Output
voltage,
V
O
V
T
otal
harmonic
distortion,
THD
%
Input voltage, V
IN
dBm
V
O
max V
CC
V
O
, THD V
IN
Output
voltage,
V
O
V
T
otal
harmonic
distortion,
THD
%
Output
voltage,
V
O
V
T
otal
harmonic
distortion,
THD
%
Pin 17
Input voltage, V
IN
dBm
V
O
, THD V
IN
V
O
, THD V
IN
Input voltage, V
IN
dBm
Output
voltage,
V
O
V
T
otal
harmonic
distortion,
THD
%
Input voltage, V
IN
dBm
ALC
output
voltage,
V
O
A
L
Cd
B
Supply voltage, V
CC
V
V
O
, THD V
IN
V
O
ALC V
CC
LA3242
No.2620-8/12
Equivalent
input
noise
voltage,
V
NI
V
Supply voltage, V
CC
V
Output
noise
voltage,
V
NO
V
Supply voltage, V
CC
V
V
NI
V
CC
V
NO
V
CC
(V
CC
= 6 V)
Output
noise
voltage,
V
NO
V
Input signal source resistance, Rg
Equivalent
input
noise
voltage,
V
NI
V
Input signal source resistance, Rg
V
NO
Rg
V
NI
Rg
Maximum
output
voltage,
V
O
m
a
xV
Load resistance, R
L
Maximum
output
voltage,
V
O
m
a
xV
Supply voltage, V
CC
V
V
O
max R
L
V
O
max V
CC
Output
voltage,
V
O
V
T
otal
harmonic
distortion,
THD
%
Input voltage, V
IN
dBm
V
oltage
gain,
VG
d
B
Supply voltage, V
CC
V
V
O
, THD V
IN
VG V
CC
LA3242
No.2620-9/12
Output
noise
voltage,
V
NO
V
Supply voltage, V
CC
V
Equivalent
input
noise
voltage,
V
NI
V
Supply voltage, V
CC
V
V
NO
V
CC
V
NI
V
CC
Equivalent
input
noise
voltage,
V
NI
V
Input signal source resistance, Rg
Crosstalk,
CT
d
B
Input frequency, f
IN
Hz
V
NI
Rg
CT f
IN
Crosstalk,
CT
d
B
Input frequency, f
IN
Hz
Crosstalk,
CT
d
B
Input frequency, f
IN
Hz
CT f
IN
CT f
IN
Crosstalk,
CT
d
B
Input frequency, f
IN
Hz
Crosstalk,
CT
d
B
Input frequency, f
IN
Hz
CT f
IN
CT f
IN
LA3242
No.2620-10/12
Ripple
rejection
ratio,
R
r
d
B
Supply voltage, V
CC
V
Ripple
rejection
ratio,
R
r
d
B
Ripple frequency, f
R
Hz
R
r
V
CC
R
r
f
R
Ripple
rejection
ratio,
R
r
d
B
Value of capacitor for ripple filter, C
r
F
Quiescent
current,
I
CCO
m
A
Ambient temperature, Ta C
R
r
C
r
I
CCO
Ta
V
oltage
gain,
VG
d
B
Ambient temperature, Ta C
Maximum
output
voltage,
V
O
m
a
xV
Ambient temperature, Ta C
VG Ta
V
O
max Ta
From the top:
Maximum
output
voltage,
V
O
m
a
xV
Ambient temperature, Ta C
Maximum
output
voltage,
V
O
m
a
xV
Ambient temperature, Ta C
V
O
max Ta
V
O
max Ta
LA3242
No.2620-11/12
No products described or contained herein are intended for use in surgical implants, life-support systems,
aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like,
the failure of which may directly or indirectly cause injury, death or property loss.
Anyone purchasing any products described or contained herein for an above-mentioned use shall:
1
Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and
distributors and all their officers and employees, jointly and severally, against any and all claims and litigation
and all damages, cost and expenses associated with such use:
2
Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on
SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees
jointly or severally.
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for
volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or
implied regarding its use or any infringements of intellectual property rights or other rights of third parties.
This catalog provides information as of December, 1997. Specifications and information herein are subject to change without notice.
DC
voltage,
V
DAC
,V
17
V
Ambient temperature, Ta C
Control
voltage
(Pin
9),
V
CONT
V
Control voltage V
CONT
on pin 9 and pin
9-controlled electronic SW ON/OFF
characteristic
Supply voltage, V
CC
V
V
DAC
, V
17
Ta
V
CONT
V
CC
Electronic SW
OFF (Break)
Electronic SW
ON (Make)
Thrshold region
Control voltage V
CONT
on pin 16 and pin
16-controlled electronic SW ON/OFF
characteristic
Electronic SW OFF
Electronic SW ON
Threshold region
Supply voltage, V
CC
V
Control
voltage(pin
16),
V
CONT
V
Output
voltage,
V
OAC
V
Residual
voltage(Pin
8),
V
8
V
Bias
current
,I
A
ALC control voltage, V
ALC CONT
V
V
CONT
V
CC
V
OAC
, V
8
, I V
ALC CONT
Starting
time,
t
s
s
Value of capacitor for ripple filter (Pin 14), C
r
F
Input
DC
voltage,
V
IN
DC
m
V
Supply voltage, V
CC
V
t
s
C
r
V
IN DC
V
CC
LA3242
No.2620-12/12
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