Preamplifier + Power Amplifier
for 3V Headphone Stereos
Overview
The LA4581MB is an auto reverse-supported preamplifier +
power amplifier IC that is intended for use in 3V headphone
stereos.
Features
.
Preamplifier muting and preamplifier output on/off can be
implemented with one pin. This IC can easily be used to
construct a set with a radio.
.
The power amplifier needs no input/output coupling
capacitor.
.
A high-frequency cut capacitor is connected to the
preamplifier input pin and the power amplifier input pin.
(Anti-buzz provision)
.
Because V
ref
AMP (r
0
= 10
) is built in, the virtual
grounding impedance is about 10
. This eliminates the
need for a large capacitor.
.
8
speaker drivable.
Package Dimensions
unit : mm
3112-MFP24S
[LA4581MB]
SANYO : MFP24S
Specifications
Maximum Ratings
at Ta = 25 C
Parameter
Symbol
Conditions
Ratings
Unit
Maximum supply voltage
V
CC
max
4.5
V
Allowable power dissipation
Pd max
530
mW
Operating temperature
Topr
20 to +75
C
Storage temperature
Tstg
40 to +125
C
Operating Conditions
at Ta = 25 C
Parameter
Symbol
Conditions
Ratings
Unit
Recommended supply voltage
V
CC
3.0
V
Operating supply voltage range
V
CC
op
1.8 to 3.6
V
Operating Characteristics
at Ta = 25 C, V
CC
= 3.0 V, f = 1 kHz, 0.775 V = 0 dBm,
R
L
= 10 k
(preamplifier), R
L
= 16
(power amplifier)
Parameter
Symbol
Output
min
typ
max
Unit
[Pre + Power]
Quiescent current
I
CCO
Rg = 2.2 k
(preamplifer) V
IN
= 0 V
17
27
mA
Voltage gain (Closed)
VG
T
V
O
= 5 dBm
65
68
71
dB
Continued on next page.
Ordering number: EN3535A
Monolithic Linear IC
LA4581MB
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
22896HA(II) No.3535-1/8
Continued from preceding page.
Parameter
Symbol
Output
min
typ
max
Unit
[Preamplifier]
Voltage gain (Open)
VGo
V
O
= 5 dBm
70
80
dB
Voltage gain (Closed)
VG1
V
O
= 5 dBm
40
dB
Maximum output voltage
V
O
max
THD = 1 %, V
CC
= 1.8 V
0.1
0.2
V
Total harmonic distortion
THD1
V
O
= 0.2 V, VG = 40 dB/NAB
0.05
0.5
%
Equivalent input noise voltage
V
N
1
Rg = 2.2 k
, B.P.F = 20 to 20 kHz
1.3
2.0
V
Crosstalk
CT1
Rg = 2.2 k
, TUNE 1 kHz
60
80
dB
Ripple rejection ratio
R
r
1
Rg = 2.2 k
, V
CC
= 1.8 V, Vr = 20 dBm,
f = 100 Hz
40
50
dB
[Power Amplifer]
Output voltage
P
O
THD = 10%
23
32
mW
Voltage gain (Closed)
VG2
V
O
= 5 dBm
25
28
31
dB
Total harmonic distortion
THD2
P
O
= 1 mW
0.4
1.0
%
Interchannel crosstalk
CT
T
V
O
= 5 dBm, R
v
= 0
30
40
dB
Output noise voltage
V
NO
Rg = 0, B.P.F = 20 to 20 kHz
24
40
V
Ripple rejection ratio
R
r
2
Rg = 0, V
r
= 20 dB, f = 100 Hz, V
CC
= 1.8 V
45
60
dB
Input resistance
R
IN
22
30
38
k
DC offset voltage
V
ODC
off
Between 13-14 and 15
90
+90
mV
Note) Power amplifier voltage gain VG2 increases by about 1 dB for min/max respectively than specified above when R
L
= 32
.
Block Diagram
Test Circuit
Unit (resistance:
, capacitance: F)
1.8 to 3.0 V
LA4581MB
No.3535-2/8
Sample Application Circuit
Pin and external part functions (when the voltage is V
CC
= 3.0 V)
Pin No.
Pin Function
1
PRE GND
2
PRE IN1R 1.8 V
v
Turns ON when pin 17 is grounded.
v
A bias resistor (2.2 k
) must be connected between pin 2 and pin 24 (V
ref
) when no head is in use.
3
PRE IN1F 1.8 V
v
Turns ON when pin 17 is floating.
v
A bias resistor (2.2 k
) must be connected between pin 3 and pin 24 (V
ref
) when no head is in use.
4
PRE NF1 1.8 V
5
PRE OUT1 1.8 V
v
Like pin 6, 10 k
load drivable.
6
SW OUT1 1.8V
v
Provides PRE AMP1 output when pin 8 is floating (PRE MUTE OFF)(equivalent to pin 5).
v
Disconnects from PRE AMP1 and sets R
IN
^
500 k
when pin 8 is at V
CC
(PRE MUTE ON).
7
POWER IN1 1.8V
v
Input resistance R
IN
7
30 k
Continued on next page.
Allowable
power
dissipation,
Pd
max
-
m
W
Ambient temperature, Ta - C
Preamplifier input is applied to pins 2,23/
pins 3,22 when SW ON/OFF, respectively.
POWER MUTE ON when
connected to GND.
Note) Pre closed loop gain VG = 40 dB/1 kHz NAB
PRE MUTE ON when
connected to VCC
Unit (resistance:
, capacitance: F)
1.8 to 3.6 V
LA4581MB
No.3535-3/8
Continued from preceding page.
Pin No.
Pin Function
8
PRE MUTE
v
When V
CC
is applied, PRE MUTE ON.
v
MUTE ON conditions: V
8IN
^
V
CC
0.2 V, inflow current I
7
7
60 A (when V
CC
= 3 V)
9
Ripple Filter REF 2.7 V(C
7
= 2.2 F to 33 F)
v
Ripple Filter, V
ref
reference
v
The V
ref
ripple rejection ratio worsens when C
7
is made smaller.
v
R
r
is 55 dB for 22 F; 35 dB for 2.2 F.
10
Ripple Filter OUT 2.7 V
v
Ripple rejection ratio: R
r
is 38 dB when C
7
= 22 F; 30 dB when C
7
= 2.2 F.
v
Outflow current I
7
max = 1 mA
11
V
CC
3.0 V
12
POWER GND
13
COMMON 1.2 V
14
POWER OUT1 1.2 V
v
CH1 output.
15
POWER OUT2 1.2 V
v
CH2 output
16
POWER MUTE 0.7 V (C
10
= 1.0 F to 4.7 F)
v
When connected to GND: POWER MUTE ON.
v
MUTE ON conditions: V
16
%
0.3 V, outflow current I
16
7
2.5 A.
v
C
10
can be used to control MUTE TIME.
v
When C
10
= 2.2 F, V
CC
=3.0 V 0.7 sec.
17
FWD/REV SW (C11
%
0.47 F)
v
When connected to GND, PRE IN1R (pin 2) and IN2R (pin 23) turn on.
v
When floating, PRE IN1F (pin 3) and IN2F (pin 22) turn on.
v
C
11
and R
7
are intended for smoothing at the time of switching.
v
REV condition: V
17
%
0.2 V.
18
POWER IN2 1.8 V
v
Input resistance R
IN
7
30 k
19
SW OUT2 1.8 V
v
Provides PRE AMP2 when pin 8 is floating (PRE MUTE OFF) (equivalent to pin 20).
v
Disconnects from PRE AMP2 and R
IN
^
500 k
when pin 8 is V
CC
(PRE MUTE ON).
20
PRE OUT2 1.8 V
v
Like pin 19, 10 k
load drivable.
21
PRE NF2 1.8V
22
PRE IN2F 1.8 V
v
Turns on when pin 17 is floating.
v
A bias resistor (2.2 k
) must be connected between pin 22 and pin 24 (V
ref
) when no head is in use.
23
PRE IN2R 1.8 V
v
Turns on when pin 17 is connected to GND.
v
A bias resistor (2.2 k
) must be connected between pin 23 and pin 24(V
ref
) when no head is in use.
24
V
ref
1.8 V
v
The reference voltage is set to 3/5
V
CC
. Because Vref AMP (r
O
7
10
) is built in, C
17
can be made smaller (1 F).
v
Inflow/outflow current I
24
= 500 A available.
Sample Application:
Radio set application.
As shown above, Radio on and
Pre Mute can be implemented with one-circuit
switch.
LA4581MB
No.3535-4/8
IC Usage Notes
1.
The power amplifier outputs and the common amplifier output are connected through resistors of about 60
. The resistors
are for common amplifier oscillation blocking.
2.
The preamplifier muting function isolates the preamplifier outputs from SW OUT. The preamplifier is on even when the
preamplifier muting is on.
3.
If transient noise is noticeable when the power supply is turned off, add the external circuit described below. Transient noise
when the power is turned off can be improved by rapidly applying the power amplifier muting.
4.
Internal equivalent circuit for each SW pin.
.
Pre-mute
.
Power mute
.
F/R SW
However, the standby current I
ST
flows even when the
power switch is off
I
ST
= (V
CC
- V
BE
)/600 k
When V
CC
= 3.0 V
I
ST
= (3.0 - 0.6)/600 k
7 4 A
Unit (resistance:
, capacitance: F)
MUTE ON condition : V
8IN
^ V
CC
0.2 V
Inflow current : I
8
7 60 A (when V
CC
= 3.0 V)
Unit (resistance:
)
MUTE ON condition : V
16
% 0.3 V
Outflow current : I
16
7 2.5 A
Unit (resistance:
, capacitance: F)
REV condition : V
17
% 0.2 V
Unit (resistance:
, capacitance: F)
LA4581MB
No.3535-5/8
Pre + Power
Quiescent
current,
Icco
m
A
Supply voltage, V
CC
V
V
oltage
gain,
VG
d
B
Preamp
Frequency, f Hz
Unit (resistance:
, capacitance: F)
Preamp
Preamp
V
oltage
gain,
VGo
d
B
Supply voltage, V
CC
V
T
otal
harmonic
distortion,
THD
%
Output voltage, V
o
V
Preamp
[Interchannel]
Preamp
Maximum
output
voltage,
V
o
m
a
xV
The base correction turns off, causing output
DC to increase, and output is obtained.
Supply voltage, V
CC
V
Crosstalk,
CT
d
B
79 dB at tune 1 kHz
Frequency, f Hz
[Between F/R]
Frequency, f Hz
89 dB at tune 1 kHz
Preamp
Preamp
equivalent
Crosstalk,
CT
d
B
Output
noise
voltage,
V
NO
F
equivalent
ch1, ch2 equivalent
Supply voltage, V
CC
V
LA4581MB
No.3535-6/8
amp
Output
voltage,
V
o
dBm
Frequency, f Hz
Drops because of 1 F at
5 kH or more when
impedance is small.
Reference
voltage,
V
ref
V
amp
Virtual grounding inflow current is I = 500 A max.
Output current, I
o
mA
Unit (resistance:
, capacitance: F)
DC
voltage,
V
DC
V
Supply voltage, V
CC
V
Power amp
DC
voltage,
V
DC
V
(Vitrual
Grounding)
Supply voltage, V
CC
V
Maximum
output
voltage,
V
O
V
Power amp
When both channels output simultaneously
Power amp
V
oltage
gain,
VG
d
B
When both channels output simultaneously
Frequency, f Hz
Supply voltage, V
CC
V
Power amp
Power amp
V
oltage
gain,
VG
d
B
Supply voltage, V
CC
V
Crosstalk,
CT
d
B
equivalent
Frequency, f Hz
When both channels output
LA4581MB
No.3535-7/8
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 February, 1996. Specifications and information herein are subject to change without notice.
Power amp
Power amp
T
otal
harmonic
distortion,THD
%
T
otal
harmonic
distortion,
THD
%
When both channels output simultaneously
When both channels output simultaneously
Supply voltage, V
CC
V
Output voltage, P
O
mW
Power amp
Power amp
T
otal
harmonic
distortion,
THD
%
Output
noise
voltage,
V
NO
V
When both channels output simultaneously
Output power, P
O
mW
Supply voltage, V
CC
V
SVRR
d
B
Power amp
Preamp
Supply voltage, V
CC
V
Supply voltage, V
CC
V
ch1 and ch2 OUT are equivalent
SVRR
d
B
LA4581MB
No.3535-8/8
PDF 
ZIP