MITSUMI MM1376

IC for Headphone Stereos MM1376
MITSUMI
IC for Headphone Stereos
Monolithic IC MM1376
Outline
This IC was developed for use in 3V headphone stereos, and combines all the basic audio circuitry for
headphone stereos on a single chip.
Recently hearing impairment caused by the high volumes of headphone stereos has become a problem, and
there has been strong demand for functions for limiting loud volumes in the sets themselves. This IC
incorporates an ALC circuit and has functions to hold the output from the headphone to a fixed level; it also
eliminates the ordinary electronic governor circuit in order to accommodate trends toward thinner sets, as
seen in the adoption of BSL motors.
Package
1. Configuration: Pre-and power amps, ALC circuit
2. Internal tape selector: A selector switch allows the user to select between normal and metal tapes.
3. Internal OCL circuit: No need for large-capacitance output capacitor
4. Preamp off function: Preamp alone can be turned off for connection to radio etc.
5. MM1376CF amp gain takes Dolby noise reduction into account
Package
SOP-22
Pin Assignment
1
COM1
12
Power output
2
Preamp non-inverted input
13
VCC
3
Preamp inverted input
14
Ripple filter
4
Metal switching output
15
Preamp off
5
Preamp output
16
Tape selector
6
Power input
17
Power input
7
Rectifier pin
18
Preamp output
8
ALC control
19
Metal switching output
9
Power output
20
Preamp inverted input
10
COM2
21
Preamp non-inverted input
11
GND1
22
GND2
22 21 20 19 18 17 16 15 14 13 12
1 2 3 4 5 6 7 8 9 10 11
SOP-22
Absolute Maximum Ratings
Item
Symbol
Ratings
Units
Operating temperature
TOPR
-10~+65
°C
Storage temperature
TSTG
-40~+125
°C
Power supply current
VCC
-0.3~+7.5
V
Power consumption
Pd
350
mW
IC for Headphone Stereos MM1376
MITSUMI
Recommended Operating Conditions
Item
Symbol
Ratings
Units
Operating temperature
TOPR
-10~65
°C
Operating voltage
VOPR
2.0~5.0
V
Electrical Characteristics
(Except where noted otherwise, Ta=25°C, VCC=3V, f=1kHz, RL1=10kΩ, RL2=16Ω)
Item
Measurement conditions
Consumption current
VIN=0V
Min. Typ. Max. Units
6
14
22
mA
Preamp unit
72
Open-circuit gain
Closed-circuit gain I
Closed-circuit gain II
Normal
Metal
Normal
Metal
Vo=-10dBm, f=1kHz
Vo=-10dBm, f=5kHz
Maximum output voltage
THD=10%
Total harmonic distortion ratio
VOUT=-10dBm
Output noise voltage
Normal
Metal
Rg=2.2k, BPF (400~30kHz)
dB
31
33.5
36
29.5
32
34.5
28
30.5
33
23
25.5
28
0.30
0.45
dB
dB
Vrms
0.05
0.5
30
75
150
20
45
100
%
µVrms
Crosstalk between channels
Rg=2.2kΩ, VOUT=-10dBm
50
70
dB
Ripple rejection
VCC=3V, VR=-20dBm, fR=100Hz Rg=2.2kΩ
45
55
dB
Output voltage with preamp off
VIN=100mVrms, Pre off
-80
-60
dBm
ALC (off) + power amp
Voltage gain
POUT=5mW
CF
24
26
28
DF
30
32
34
-2
0
2
30
50
Voltage gain difference between channels
Maximum output current
THD=10%, RL=16Ω
Total harmonic distortion ratio
POUT=5mW
Crosstalk between channels
POUT=5mW
Output noise voltage
Ripple rejection
Rg=0Ω, BPF (400~30kHz)
0.5
35
dB
dB
mW
1.5
45
%
dB
CF
85
200
DF
135
250
µVrms
VCC=3V, VR=-20dBm
CF
35
45
fR=100Hz, Rg=0Ω
DF
35
40
19
24
29
kΩ
-34
-30
-26
dBm
Input resistance
dB
ALC (on) + power amp
Power amp output voltage
VIN=-40dBm
ALC initiation input voltage
CF
-56
DF
-62
ALC width
Input width for output from start of up to +4dB
ALC total harmonic distortion
VIN=-40dBm
Noise of preamp+power amp+ALC
Rg=2.2kΩ (Pre amp), Noise of preamp+power amp
30
dBm
40
dB
0.5
1.5
CF
1.5
6
DF
2.8
6
%
mVrms
IC for Headphone Stereos MM1376
MITSUMI
Application Circuits
Characteristics
Preamp Gain- Frequency
60.0
55.0
50.0
45.0
40.0
volt 35.0
dB 30.0
25.0
lin 20.0
15.0
10.0
5.0
0.
1.0
ALC + power amp (32 dB) VIN-VOUT RL=16ohm
10
ALC OFF
0
-10
VOUT
(dBV)
Normal
Metal
-20
ALC ON (ADJUST)
-30
-40
ALC ON (max.)
-50
-60
-80 -70 -60 -50 -40 -30 -20 -10
10.0 100.0 1.0k
10.0k 100.0k 1.0x
Frequency (log)
10.0x
VIN (dBV)
0