NJM2776
Headphone Amplifier for Portable Audio
s
GENERAL DESCRIPTION
The
NJM2776
is a low voltage headphone amplifier for
portable audio applications.
The
NJM2776
operates directly for one battery supply with
+
+
independent power supply terminals (V 1 and V 2).
Also it provides shock-noise less standby mode.
The
NJM2776
is suitable for portable MD, portable CD and
others.
s
PACKAGE OUTLINE
NJM2776RB2
s
FEATURES
q
Operating Voltage
V 1(from step-up converter) =1.8 to 4.5V (however, V 1 > V 2)
+
+
+
V 2(from battery)
=0.9 to 4.5V (however, V 1 > V 2)
+
+
+
q
Low Operating Current
I
CC4
(V 1 side)=200µA typ. (V 1=2.3V, V 2=1.2V, No signal)
+
+
+
I
CC3
(V 2 side)=350µA typ. (V 1=2.3V, V 2=1.2V, No signal)
+
+
+
q
Supply Current in Standby mode I
CC2
(V 1 side)=25µA typ. (V 1=2.3V, V 2=1.2V)
+
+
+
I
CC1
(V 2 side)= 6µA typ. (V 1=2.3V, V 2=1.2V)
q
Output Power Exceeds
P
O
=8.5mW typ. (R
L
=16Ω, THD=10%)
q
Shock-noise less Standby mode
q
Bipolar Technology
q
Package Outline
TVSP10
+
+
+
s
PIN CONFIGURATION AND BLOCK DIAGRAM
V
+
2
1
10
GND
OUT 1
2
9
OUT 2
+
-
-
+
IN 1
3
8
IN 2
STANDBY TC
4
BIAS
7
STANDBY
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
V2
OUT1
IN1
STADBY_TC
+
V1
VREF
STANDBY
IN2
OUT2
GND
+
REG
V
+
1
5
VREF AMP
6
VREF
-1-
NJM2776
s
ABSOLUTE MAXIMUM RATINGS
(Ta=25°C)
PARAMETER
SYMBOL
+
Supply Voltage
V
Power Dissipation
P
D
Operating Temperature range
T
opr
Storage Temperature Range
T
stg
RATINGS
5
(note)
320
-20 to +75
-40 to +125
UNIT
V
mW
°C
°C
s
RECOMMENDED OPERATING CONDITIONS
PARAMETER
SYMBOL
TEST CONDITION
+
V1
-
Operating Voltage Range
+
-
V2
+
+
MIN.
1.8
0.9
TYP.
2.3
1.2
MAX.
4.5
4.5
UNIT
V
s
ELECTRICAL CHARACTERISTICS
(Ta=25°C, V 1=2.3V, V 2=1.2V, V
IN
=-30dBV (31.6mVrms), f=1kHz,
R
L
=16Ω, Active mode, unless otherwise specified)
●Power
Supply
TEST CONDITION
PARAMETER
SYMBOL
MIN.
TYP.
MAX.
UNIT
pin
+
+
Operating Current
I
CC0
V 1=0V
V2
-
-
1.0
+
I
CC1
V2
-
6.0
10.0
Standby mode
+
µ
A
I
CC2
V1
-
25
35
+
I
CC3
V2
-
350
750
No signal
+
I
CC4
V1
-
200
400
+
I
CC5
V2
-
2.5
-
P
O
=0.1mW+0.1mW
mA
+
-
200
-
V1
I
CC6
Reference Voltage
No signal
0.50
0.60
0.65
V
V
R E F
●Amplifier
PARAMETER
Closed loop Gain
Output Power
Total Harmonic Distortion
Output Noise Voltage
Channel Separation
Mute Level
Supply Voltage
Rejection Ratio
SYMBOL
G
V
P
O
THD
V
NO
CS
MUTE
PSRR1
PSRR2
●Mode
Control
PARAMETER
High Level Input Voltage
Low Level Input Voltage
Standby mode
1kHz Band Pass
+
V 1=1.8V + 0.1Vrms
+
V 2=0.9V
+
V 1=1.8V
+
V 2=0.9V + 0.1Vrms
TEST CONDITION
V
IN
=High Level
V
IN
=Low Level
TEST CONDITION
THD=10%
P
O
=1mW
A-Weighted
MIN.
10.0
5.0
-
-
44
-
46
70
TYP.
11.5
8.5
0.20
-100
(10.0)
MAX.
12.5
-
0.50
-96
(15.8)
UNIT
dB
mW
%
dBV
(µV)
55
-100
52
77
-
-80
-
dB
dB
dB
-
SYMBOL
V
IH
V
IL
MIN.
1.2
0.0
TYP.
-
-
MAX.
+
V1
0.3
UNIT
V
s
MODE SWITHCH FUNCTION
●STANDBY
(7PIN)
PARAMETER
CONTROL SIGNAL
Standby
L, open
Active
H
STATUS
IC is non-active.
IC is active.
-2-
NJM2776
s
APPLICATION CIRCUIT
V
+
2
C1
22
µ
F
C2
330
µ
F
GND
C10
330
µ
F
OUT 1
OUT 2
C9
0.22
µ
F
IN 2
C8
0.47
µ
F
V
+
1
Active
STANDBY
Standby
R2
10
Ω
ＮＪＭ２７７６
ＮＪＭ２７７６
ＮＪＭ２７７６
ＮＪＭ２７７６
R1
C3
10
Ω
0.22
µ
F
IN 1
C4
0.47
µ
F
STANDBY TC
C5
0.33
µ
F
V
+
1
C6
22
µ
F
VREF
C7
22
µ
F
Note) Recommended the capacitors
C1, C3, C6 and C9
are featuring higher frequency efficiency
to prevent the oscillation.
-5-
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