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 Vref AMP (r0=10Ω) is built in, the virtual
grounding impedance is about 10 Ω. This eliminates the
need for a large capacitor.
.8Ωspeaker drivable.
Package Dimensions
unit : mm
3112-MFP24S
[LA4581MB]
SANYO : MFP24S
Specifications
Maximum Ratings atTa=25°
C
Parameter Symbol Conditions Ratings Unit
Maximum supply voltage VCC 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 atTa=25°
C
Parameter Symbol Conditions Ratings Unit
Recommended supply voltage VCC 3.0 V
Operating supply voltage range VCC op 1.8 to 3.6 V
Ordering number: EN3535A
Monolithic Linear IC
LA4581MB
Any and all SANYO products described or contained herein do not have specifications that can handle
applications that require extremely high levels of reliability, such as life-support systems, aircraft’s
control systems, or other applications whose failure can be reasonably expected to result in serious
physical and/or material damage. Consult with your SANYO representative nearest you before using
any SANYO products described or contained herein in such applications.
SANYO assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other
parameters) listed in products specifications of any and all SANYO products described or contained
herein.
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
22896HA(II) No.3535-1/10
Operating Characteristics atTa=25°
C, VCC =3.0V,f=1kHz, 0.775 V = 0 dBm,
RL=10kΩ(preamplifier), RL=16Ω(power amplifier)
Parameter Symbol
Output
min typ max Unit
[Pre + Power]
Quiescent current ICCO Rg = 2.2 kΩ(preamplifer) VIN = 0 V 17 27 mA
Voltage gain (Closed) VGTVO= –5 dBm 65 68 71 dB
[Preamplifier]
Voltage gain (Open) VGo VO= –5 dBm 70 80 dB
Voltage gain (Closed) VG1 VO= –5 dBm 40 dB
Maximum output voltage VOmax THD=1%,V
CC = 1.8 V 0.1 0.2 V
Total harmonic distortion THD1 VO= 0.2 V, VG = 40 dB/NAB 0.05 0.5 %
Equivalent input noise voltage VN1 Rg = 2.2 kΩ, B.P.F = 20 to 20 kHz 1.3 2.0 µV
Crosstalk CT1 Rg = 2.2 kΩ, TUNE 1 kHz 60 80 dB
Ripple rejection ratio Rr1Rg = 2.2 kΩ,V
CC = 1.8 V, Vr = –20 dBm,
f = 100 Hz 40 50 dB
[Power Amplifer]
Output voltage POTHD = 10% 23 32 mW
Voltage gain (Closed) VG2 VO= –5 dBm 25 28 31 dB
Total harmonic distortion THD2 PO= 1 mW 0.4 1.0 %
Interchannel crosstalk CTTVO= –5 dBm, Rv=0Ω30 40 dB
Output noise voltage VNO Rg = 0, B.P.F = 20 to 20 kHz 24 40 µV
Ripple rejection ratio Rr2 Rg=0,V
r= –20 dB, f = 100 Hz, VCC = 1.8 V 45 60 dB
Input resistance RIN 22 30 38 kΩ
DC offset voltage VODCoff 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=32Ω.
LA4581MB
No.3535-2/10
Block Diagram
Test Circuit
Unit (resistance: Ω, capacitance: F)
1.8 to 3.0 V
LA4581MB
No.3535-3/10
Sample Application Circuit
Pin and external part functions (when the voltage is VCC = 3.0 V)
Pin No. Pin Function
1 PRE GND
2PRE IN1R 1.8 V
vTurns ON when pin 17 is grounded.
vA bias resistor (2.2 kΩ) must be connected between pin 2 and pin 24 (Vref) when no head is in use.
3PRE IN1F 1.8 V
vTurns ON when pin 17 is floating.
vA bias resistor (2.2 kΩ) must be connected between pin 3 and pin 24 (Vref) when no head is in use.
4 PRE NF1 1.8 V
5PRE OUT1 1.8 V
vLike pin 6, 10 kΩload drivable.
6SW OUT1 1.8V
vProvides PRE AMP1 output when pin 8 is floating (PRE MUTE OFF)(equivalent to pin 5).
vDisconnects from PRE AMP1 and sets RIN ^500 kΩwhen pin 8 is at VCC (PRE MUTE ON).
7POWER IN1 1.8V
vInput resistance RIN 730 kΩContinued on next page.
Allowable power dissipation, Pd max – mW
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: Ω, capacitance: F)
1.8 to 3.6 V
LA4581MB
No.3535-4/10
Continued from preceding page.
Pin No. Pin Function
8PRE MUTE
vWhen VCC is applied, PRE MUTE ON.
vMUTE ON conditions: V8IN ^VCC – 0.2 V, inflow current I7760 µA (when VCC =3V)
9Ripple Filter REF 2.7 V(C7= 2.2 µF to 33 µF)
vRipple Filter, Vref reference
vThe Vref ripple rejection ratio worsens when C7is made smaller.
vRris 55 dB for 22 µF; 35 dB for 2.2 µF.
10 Ripple Filter OUT 2.7 V
vRipple rejection ratio: Rris 38 dB when C7= 22 µF; 30 dB when C7= 2.2 µF.
vOutflow current I7max=1mA
11 VCC 3.0 V
12 POWER GND
13 COMMON 1.2 V
14 POWER OUT1 1.2 V
vCH1 output.
15 POWER OUT2 1.2 V
vCH2 output
16
POWER MUTE 0.7 V (C10 = 1.0 µF to 4.7 µF)
vWhen connected to GND: POWER MUTE ON.
vMUTE ON conditions: V16 %0.3 V, outflow current I16 72.5 µA.
vC10 can be used to control MUTE TIME.
vWhen C10 = 2.2 µF, VCC =3.0 V 0.7 sec.
17
FWD/REV SW (C11 %0.47 µF)
vWhen connected to GND, PRE IN1R (pin 2) and IN2R (pin 23) turn on.
vWhen floating, PRE IN1F (pin 3) and IN2F (pin 22) turn on.
vC11 and R7are intended for smoothing at the time of switching.
vREV condition: V17 %0.2 V.
18 POWER IN2 1.8 V
vInput resistance RIN 730 kΩ
19 SW OUT2 1.8 V
vProvides PRE AMP2 when pin 8 is floating (PRE MUTE OFF) (equivalent to pin 20).
vDisconnects from PRE AMP2 and RIN ^500 kΩwhen pin 8 is VCC (PRE MUTE ON).
20 PRE OUT2 1.8 V
vLike pin 19, 10 kΩload drivable.
21 PRE NF2 1.8V
22 PRE IN2F 1.8 V
vTurns on when pin 17 is floating.
vA bias resistor (2.2 kΩ) must be connected between pin 22 and pin 24 (Vref) when no head is in use.
23 PRE IN2R 1.8 V
vTurns on when pin 17 is connected to GND.
vA bias resistor (2.2 kΩ) must be connected between pin 23 and pin 24(Vref) when no head is in use.
24 Vref 1.8 V
vThe reference voltage is set to 3/5 ×VCC. Because Vref AMP (rO710 Ω) is built in, C17 can be made smaller (1 µF).
vInflow/outflow current I24 = ± 500 µA available.
Sample Application:
Radio set application.
As shown above, Radio on and
Pre Mute can be implemented with one-circuit
switch.
LA4581MB
No.3535-5/10
IC Usage Notes
1. The power amplifier outputs and the common amplifier output are connected through resistors of about 60 Ω. 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
Ω
Ω
However, the standby current IST flows even when the
power switch is off
IST =(V
CC –V
BE)/600 kΩ
When VCC = 3.0 V
IST = (3.0 – 0.6)/600 kΩ74µA
Unit (resistance: Ω, capacitance: F)
MUTE ON condition : V8IN ^VCC – 0.2 V
Inflow current : I8760 µA (when VCC = 3.0 V)
Unit (resistance: Ω)
MUTE ON condition : V16 %0.3 V
Outflow current : I16 72.5 µA
Unit (resistance: Ω, capacitance: F)
REV condition : V17 %0.2 V
Unit (resistance: Ω, capacitance: F)
LA4581MB
No.3535-6/10
Pre + Power
Quiescent current, Icco – mA
Supply voltage, VCC –V
Voltage gain, VG – dB
Preamp
Frequency,f–Hz
Unit (resistance: Ω, capacitance: F)
Preamp Preamp
Voltage gain, VGo – dB
Supply voltage, VCC –V
Total harmonic distortion, THD – %
Output voltage, Vo–V
Preamp [Interchannel]
Preamp
Maximum output voltage, Vomax–V
The base correction turns off, causing output
DC to increase, and output is obtained.
Supply voltage, VCC –V
Crosstalk, CT – dB
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 – dB
Output noise voltage, VNO –µF
equivalent
ch1, ch2 equivalent
Supply voltage, VCC –V
LA4581MB
No.3535-7/10
amp
Output voltage, Vo– dBm
Frequency,f–Hz
Drops because of 1 µF at
5 kH or more when
impedance is small.
Reference voltage, Vref – V
amp
Virtual grounding inflow current is I = 500 µA max.
Output current, Io–mA
Unit (resistance: Ω, capacitance: F)
DC voltage, VDC –V
Supply voltage, VCC –V
Power amp
DC voltage, VDC –V
(Vitrual
Grounding)
Supply voltage, VCC –V
Maximum output voltage, VO–V
Power amp
When both channels output simultaneously
Power amp
Voltage gain, VG – dB
When both channels output simultaneously
Frequency,f–Hz
Supply voltage, VCC –V
Power amp
Power amp
Voltage gain, VG – dB
Supply voltage, VCC –V
Crosstalk, CT – dB
equivalent
Frequency,f–Hz
When both channels output
LA4581MB
No.3535-8/10
Power amp Power amp
Total harmonic distortion,THD – %
Total harmonic distortion, THD – %
When both channels output simultaneously
When both channels output simultaneously
Supply voltage, VCC –V Output voltage, PO–mW
Power amp Power amp
Total harmonic distortion, THD – %
Output noise voltage, VNO –µV
When both channels output simultaneously
Output power, PO–mW Supply voltage, VCC –V
SVRR – dB
Power amp Preamp
Supply voltage, VCC –V Supply voltage, VCC –V
ch1 and ch2 OUT are equivalent
SVRR – dB
LA4581MB
No.3535-9/10
LA4581MB
PS No.3535-10/10
Specifications of any and all SANYO products described or contained herein stipulate the performance,
characteristics, and functions of the described products in the independent state, and are not guarantees
of the performance, characteristics, and functions of the described products as mounted in the customer’s
products or equipment. To verify symptoms and states that cannot be evaluated in an independent device,
the customer should always evaluate and test devices mounted in the customer’s products or equipment.
SANYO Electric Co., Ltd. strives to supply high-quality high-reliability products. However, any and all
semiconductor products fail with some probability. It is possible that these probabilistic failures could
give rise to accidents or events that could endanger human lives, that could give rise to smoke or fire,
or that could cause damage to other property. When designing equipment, adopt safety measures so
that these kinds of accidents or events cannot occur. Such measures include but are not limited to protective
circuits and error prevention circuits for safe design, redundant design, and structural design.
In the event that any or all SANYO products(including technical data,services) described or
contained herein are controlled under any of applicable local export control laws and regulations,
such products must not be exported without obtaining the export license from the authorities
concerned in accordance with the above law.
No part of this publication may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying and recording, or any information storage or retrieval system,
or otherwise, without the prior written permission of SANYO Electric Co. , Ltd.
Any and all information described or contained herein are subject to change without notice due to
product/technology improvement, etc. When designing equipment, refer to the “Delivery Specification”
for the SANYO product that you intend to use.
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.
