Ordering number: EN 2651B
Monolithic Linear IC
LA3246
Stereo Preamplifier for Compact Double Cassette
Playback-only Use
Overview
The LA3246 is a stereo preamplifier IC for double cassette tape playback-only use. The LA3246 is intended for use in portable radio-cassette tape recorders and tape decks.
Applications
. Stereo compact cassette player for playback-only use
. Stereo cassette deck player
Functions
. Preamplifier × 2, Mixing amplifier × 1, Electronic switch × 6
Features
Package Dimensions
unit : mm
3021B-DIP20
[LA3246]
SANYO : DIP20 (300 mil)
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On-chip electronic switch for input select (auto reverse or A deck/B deck select)
On-chip electronic switch for normal/higher dubbing select and electronic switch for metal/normal tape select
Wide operating voltage range (VCC op = 3.5 to 14 V) With output MIX pin (for music select control)
Low noise voltage range (VNI = 0.9 µV typ, Rg = 2.2 k Ω NAB)
Can be used in conjunction with the LA3240, 3241, 3242 to easily make up a doublecassette dubbing system.
Specifications
Maximum Ratings at Ta = 25°C
Parameter |
Symbol |
Conditions |
Ratings |
Unit |
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Maximum supply voltage |
VCC max |
|
16 |
V |
Allowable power dissipation |
Pd max |
|
500 |
mW |
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Operating temperature |
Topr |
|
±20 to +75 |
°C |
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Storage temperature |
Tstg |
|
±40 to +125 |
°C |
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Maxiumum Ratings at Ta = 25°C |
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Parameter |
Symbol |
Conditions |
Ratings |
Unit |
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|
|
|
Recommended supply voltage |
VCC |
|
6 |
V |
Operating voltage range |
VCC op |
|
3.5 to 14 |
V |
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
D3097HA(II)/41594HK/N107TA, TS No.2651-1/13
LA3246
Operating Characteristics at Ta = 25°C, V CC = 6.0 V, RL = 10 kΩ, f = 1 kHz, 0 dB = 0.775 V
Parameter |
Symbol |
Conditions |
min |
typ |
max |
Unit |
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Quiescent current |
Icco |
Nor/Nor speed forward |
5 |
7 |
12 |
mA |
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Iccs |
Metal/High speed forward |
7 |
10 |
17 |
mA |
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Voltage gain (Open) |
VGo |
|
75 |
85 |
|
dB |
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Voltage gain (Closed) |
VG |
Nor/Nor speed, NAB |
39.5 |
40.5 |
41.5 |
dB |
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Total harmonic distortion |
THD |
VO = 0.65 V, Nor/Nor speed |
|
0.03 |
0.2 |
% |
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Maximum output voltage |
VO max |
THD = 1%, Nor/Nor speed |
0.7 |
1.2 |
|
V |
|
Crosstalk (between channels) |
CT1 |
VO = ±5 dBm, Rg = 2.2 kΩ, Nor/Nor speed |
50 |
65 |
|
dB |
|
Crosstalk (between F/R) |
CT2 |
VO = ±5 dBm, Rg = 2.2 kΩ, Nor/Nor speed |
50 |
65 |
|
dB |
|
Channel balance |
VBL |
VIN = ±50 dBm |
|
0 |
2 |
dB |
|
Equivalent input noise voltage |
VNI |
Rg = 2.2 kΩ, B.P.F 20 Hz to 20 kHz, Nor/Nor speed |
|
0.9 |
1.7 |
µV |
|
MIX output voltage |
VOMIX |
VO1, VO2 = 0 dBm |
±3 |
0 |
+3 |
dB |
|
Ripple filter output current |
IF OUT |
|
|
10 |
15 |
mA |
|
Electronic switch ON-state |
Ron |
Between P1 to P4 and 5, between pin 16 and 17 |
|
100 |
250 |
Ω |
|
resistance |
Between P1 to P7 and 10, between pin 10 and 14 |
|
30 |
70 |
Ω |
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DC feedback resistance |
RF |
|
240 |
300 |
360 |
Ω |
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Input bias current |
IF |
|
|
0.5 |
3.0 |
µA |
Allowable power dissipation, Pd max ± mW
Pd max ± Ta
Ambient temperature, Ta ± °C
Equivalent Circuit Block Diagram
Top view
No.2651-2/13
LA3246
Unit (resistance: Ω, capacitance: F)
Note 1. The output frequency characteristic for Nor Tape/High speed mode (pin 6: High, pin 15: Low) and that for Metal Tape/Nor speed mode (pin 6: Low, pin 15: Low) are set to be the same.
2.Since the input bias current flows out of pins 1, 2 and pins 19, 20, a resistor (recommended value: 30 kΩ to 350 kΩ, maximum value: 500 kΩ) must be connected a coupling capacitor in series with these pins.
3.*: A capacitor must be connected to the input to absorb a surge.
4.The electronic select switching level is approximately 1/2 × (VCC±0.9).
5.The value of the capacitor connected to pin 12 can be increased/decreased to adjust starting time ts at the time of application of VCC. (C = 100 µF, t s = 0.4 s.) If the capacitor value is made less than 47 µF, the ripple rejection will get worse.
6.No capacitor is connected to pin 13. (Even if connected, the ripple can not be rejected.)
7.Extreme caution should be exercised when handling the IC as it is subject to dielectric breakdown.
No.2651-3/13
LA3246
Sample Printed Circuit Pattern (Cu-foiled area)
Unit (resistance: Ω, capacitance: F)
IC Usage Notes
(1)It is recommended to connect a surge absorbing capacitor across input pins 1, 2 and GND and across input pins 19, 20 and GND.
(2)The base of a PNP transistor is connected to input pins 1, 2 and 19, 20. If an electrolytic capacitor is connected in series with the input pins, connect input resistor RIN must not exceed 500 kΩ. (Reason: To minimize the variation in output DC voltage at the time of input switching)
Ω
If a resistor of more than 500 kΩ is connected across input pin and GND, the noise (output) caused by amp 1 and amp 2 select is liable to increase at the time of F/R switching.
No.2651-4/13
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