MITSUMI
IC for Headphone Stereos LAG673
IC for Headphone Stereos
Monolithic IC LAG673
Outline
This IC was developed for use in 3 V headphone stereos. It incorporates dual preamp, power amp, electronic
volume and motor control circuits; because it requires extremely few external components, it can be used in a
simple circuit configuration.
Features
1. Broad operating voltage range of 2.0 to 5.0 V
2. Few external components required
3. Well-balanced electronic VR, A-curve attenuation characteristic obtained with B-curve VR
4. Internal motor control circuit, with noise from motor driving unit suppressed
5. Fast forward possible using the forced-on pin
Package
SOP-28B (LAG673F)
SDIP-30A (LAG673D)
Absolute Maximum Ratings
Item
Symbol
Ratings
Units
Operating temperature
T
OPR
-20~+65
C
Storage temperature
T
STG
-40~+125
C
Power supply current
V
CC
-0.3~+7.5
V
Operating voltage
Vop
2.0~5.0
V
Power consumption
Pd
450 (SOP-28B)
mW
750 (SDIP-30A)
MITSUMI
IC for Headphone Stereos LAG673
Electrical Characteristics
(Except where noted otherwise, Ta=25
C)
Item
Symbol
Measurement conditions
Min. Typ. Max. Units
Consumption current
I
CC
V
IN
=0V, I
M
=0mA
18
25
mA
(excluding motor speed controller unit)
Preamp unit (Ta=25
C)
Open-circuit gain
Gvo
Vo=-10dBm, R
L
=
72
dB
Closed-circuit gain
Gvc
Vo=-10dBm
40
42
44
dB
Maximum output voltage
Vom
THD=10%
0.30
0.45
Vrms
Total harmonic distortion ratio
THD
V
OUT
=400mVrms
0.05
0.5
%
Output noise voltage
Vno
V
IN
=0V, Rg=2.2k
, BPF=30Hz~20kHz
150
300
Vrms
Input impedance
Zin
V
OUT
=-10dBm
18
22
k
Crosstalk between channels
C T
Rg=2.2k
, V
OUT
=-10dBm
30
dB
Output voltage with preamp off
Vooff
V
IN
=100mVrms
-50
dB
Output resistance with preamp off
Rooff
10
k
Input resistance with preamp off
Rioff
10
k
Attenuator unit (Ta=25
C)
Maximum input voltage
Vi max.
0.2
Vrms
Maximum attenuation
Va max.
Vcont=min.
66
dB
Attenuation error
Vaerr
Vcont=max.
0
dB
Input impedance
Zia
15
20
k
Control pin input resistance
Zicot
100
k
Power amp unit (Ta=25
C)
Voltage gain
Gv
P
OUT
=5mW
26
28
30
dB
Voltage gain difference between channels
Gv
Vcont=max.
0
3
dB
Maximum output power I
Pom
THD=10%, R
L
=32
20
28
mW
Maximum output power II
Pom
THD=10%, R
L
=16
30
mW
Total harmonic distortion ratio
THD
P
OUT
=5mW
0.2
2.0
%
Crosstalk between channels
C T
P
OUT
=5mW
45
55
dB
Output noise voltage
Vn
Rg=2.2k
, Vcont=min.
0.25
1.0
mVrms
Ripple rejection
RR
100Hz, 100mVp-p
42
50
dB
Noise of preamp + power amp
Vnto
V
IN
=0V, Rg=2.2k
, Vcont=max.
6
9
mVrms
Motor control unit (Ta=25
C)
Consumption current
IMC
3.0
5.0
mA
Startup current
IMS
500
mA
Reference voltage
Vref
Between RML-ADJ pins
0.72
0.80
0.87
V
Reference voltage fluctuation I
Vref1
V
CC
between 2.0 and 5.0V
*
0.05
%/V
Reference voltage fluctuation II
Vref2
I
M
between 25 and 250 mA
0.01
%/mA
Reference voltage fluctuation III
Vref3
Ta between -10 and 50
C
0.01
%/
C
Current coefficient
K
32
38
43
Current coefficient fluctuation I
K1
V
CC
between 2.0 and 6.5 V
0.5
%/V
Current coefficient fluctuation II
K2
I
M
between 25 and 250 mA
0.05
%/mA
Current coefficient fluctuation III
K3
Ta between -10 and 60
C
0.02
%/
C
Output voltage on forced on
VCEsa
T
M
=200mA
0.6
V
Input resistance on forced on
Rion
5.6
k
Leakage current on forced off
IML
200
A
Input resistance on forced off
Ricon
33
k
Conditions: V
CC
=3.0 V, I
M
= 100 mA Motor: M25E-7 (Mitsumi model)
*
Voltage drift between pins 17 and 13
V
RL
K=-------------
R
1
I
M
MITSUMI
IC for Headphone Stereos LAG673
Block Diagram
1: The motor speed potentiometer is 1.5 k
(assuming the motor used is Mitsumi M25E-7; if the optimal
adjustment range is not obtained using a different motor, add a fixed resistance).
2: RML = motor load correction resistance
3: Connecting the preamp off pin to +V
CC
turns the preamp circuits off.
4: Connecting the motor forced-on pin to +V
CC
turns the motor on (no control).
5: in circles are pin numbers for a DIP-30P package; numbers in parentheses ( ) are for an SOP-28B
package.
6: In the DIP-30P package, pins 15 and 16 are NC.
7: Ca is a 100,000 pF capacitor used to prevent oscillation of the 1/2 V
CC
amp circuit.
MITSUMI
IC for Headphone Stereos LAG673
Characteristics
100
60
50
40
30
20
10
80
70
10
100
1k
10k
100k
Frequency (Hz)
V
CC
=3.0V
When V
R
=max.
TOTAL GAIN
POWER AMP GAIN
Gain (dB)
-10
-20
-30
-40
-50
1.0
2.0
3.0
4.0
5.0
0
Ripple rejection (V)
PREAMP OFF
V
R
=max.
F
R
=100Hz
V
R
=100mVrms
R
L
=16
Ripple rejection rate-V
CC
Power supply voltage (dB)
-10
-20
-30
-40
-50
100
1k
10k
100k
Frequency (Hz)
V
CC
=3.0V
Crosstalk frequency
Crosstalk (dB)
40
50
60
70
30
20
10
Power supply voltage (V)
1.0
2.0
3.0
4.0
5.0
0
5
10
15
20
I
CC
-V
CC
R
L
=16
R
L
=32
I
OC
(R
L
=16
)
Power supply output
(THD=10%) P
OUT
max. (mW)
No-load consumption current (mA)
100
10
1
0.1
0.1
1
10
100
Power supply output (mW)
V
CC
=1.8V
V
CC
=2.0V
V
CC
=3.0V
THD-P
OUT
Total harmonic
distortion ratio (%)
THD-V
OUT
10.0
1.0
0.1
0.01
-30
-20
-10
0
Output voltage (dBm)
V
CC
=1.8V
V
CC
=2.0V
V
CC
=3.0V
Total harmonic distortion ratio (%)
0
-20
-40
-60
-80
0/6
1/6
2/6
3/6
4/6
5/6
6/6
(min.)
(max.)
Voltage controllability
(B curve mechanical volume knob)
V
CC
=3.0V
V
ATT
-V
CONT
Output voltage attenuation (dB)
Preamp
Power amp
P
OUT.
Power amp
Power amp
Voltage gain vs. Frequency
Attenuator
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