NJM2776
-1-
Headphone Amplifier for Portable Audio
■
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.
■
FEATURES
●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)
●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)
●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)
●Output Power Exceeds P
O
=8.5mW typ. (R
L
=16Ω, THD=10%)
●Shock-noise less Standby mode
●Bipolar Technology
●Package Outline MSOP10 (TVSP10)*
*MEET JEDEC MO-187-DA / THIN TYPE
■
PIN CONFIGURATION AND BLOCK DIAGRAM
■
PACKAGE OUTLINE
NJM2776RB2
MSOP10 (TVSP10)
STA NDBY TC
STANDBY
GND
IN 1
OUT 1
OUT 2
IN 2
V
+
2
VREF
V
+
1
VREF AMP
REG
BIAS
+
-
+
-
1
2
3
4
5 6
7
8
9
10
1. V
+
2
2. OUT1
3. IN1
4. STADBY_TC
5. V
+
1
6. VREF
7. STANDBY
8. IN2
9. OUT2
10. GND
NJM2776
- 2 -
■
ABSOLUTE MAXIMUM RATINGS
(Ta=25°C)
PARAMETER SYMBOL RATINGS UNIT
Supply Voltage V
+
5 V
Power Dissipation P
D
320
(note)
mW
Operating Temperature range T
opr
-20 to +75 °C
Storage Temperature Range T
stg
-40 to +125 °C
■
RECOMMENDED OPERATING CONDITIONS
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
V
+
1 - 1.8 2.3 4.5
Operating Voltage Range V
+
2 - 0.9 1.2 4.5
V
■ 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 pin
MIN. TYP. MAX. UNIT
I
CC0
V
+
1=0V V
+
2 - - 1.0
I
CC1
V
+
2 - 6.0 10.0
I
CC2
Standby mode V
+
1 - 25 35
I
CC3
V
+
2 - 350 750
I
CC4
No signal V
+
1 - 200 400
µ
A
I
CC5
V
+
2 - 2.5 -
Operating Current
I
CC6
P
O
=0.1mW+0.1mW V
+
1 - 200 - mA
Reference Voltage V
REF
No signal 0.50 0.60 0.65 V
●Amplifier
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Closed loop Gain G
V
10.0 11.5 12.5
dB
Output Power P
O
THD=10% 5.0 8.5 -
mW
Total Harmonic Distortion THD P
O
=1mW - 0.20 0.50
%
Output Noise Voltage V
NO
A-Weighted -
-100
(10.0)
-96
(15.8)
dBV
(µV)
Channel Separation CS 44 55 -
dB
Mute Level MUTE Standby mode
1kHz Band Pass - -100 -80
dB
PSRR1 V
+
1=1.8V + 0.1Vrms
V
+
2=0.9V 46 52 -
Supply Voltage
Rejection Ratio
PSRR2 V
+
1=1.8V
V
+
2=0.9V + 0.1Vrms 70 77 -
dB
●Mode Control
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
High Level Input Voltage V
IH
V
IN
=High Level 1.2 - V
+
1
Low Level Input Voltage V
IL
V
IN
=Low Level 0.0 - 0.3
V
■
MODE SWITHCH FUNCTION
●STANDBY (7PIN)
PARAMETER CONTROL SIGNAL STATUS
Standby L, open IC is non-active.
Active H IC is active.
NJM2776
-3-
■
TERMINAL DESCRIPTION
PIN No. SYMBOL EQUIVALENT CIRCUIT VOLTAGE NOTE
2,9 OUT1, OUT2
0.6V
3,8 IN1, IN2
0.6V
4 STANDBY_TC
1.2V
6 VREF
0.6V
V
+
1
GND
VREF
IN
20K
GND
V
+
2
OUT
VREF
5K
15K
GND
V
+
2
VREF
V
+
1
100
STANDBY_TC
V+1
88k
GND
680
400
NJM2776
- 4 -
PIN No. SYMBOL EQUIVALENT CIRCUIT VOLTAGE NOTE
7 STANDBY
-
V
+
1
GND
STANDBY
120k
300k
680
NJM2776
-5-
■
APPLICATION CIRCUIT
V
+
1
Active
Standby
STA NDBY TC
STA NDBY
GND
IN 1
OUT 1
OUT 2
IN 2
V
+
2
VREF
V
+
1
ＮＪＭ
ＮＪＭ
ＮＪＭ
ＮＪＭ２７７６
２７７６
２７７６
２７７６
22
µ
F
22
µ
F
22
µ
F
0.47
µ
F
330
µ
F
0.47
µ
F
330
µ
F
0.33
µ
F
0.22
µ
F
10
Ω
0.22
µ
F
10
Ω
C6
C1
C2
C3
R1
C4
C5
C8
C9
R2
C10
C7
Note) Recommended the capacitors C1, C3, C6 and C9 are featuring higher frequency efficienc
y
to prevent the oscillation.
NJM2776
- 6 -
■
APPLICATION NOTE
1. Procedure for Supplying Power
Supply the power to first V
+
2(Battery side) and then V
+
1(Step-up Converter side).
2. Input Dynamic Voltage Range
The reference voltage is fixed at 0.6V. Therefore input dynamic voltage range is not proportion to the power
supply voltage.
The input signal over dynamic range makes distortion. For prevent the distortion, adjust the maximum input
signal level.
3. Charge Sequence
Pop noise may not be happened with mode switch operation once output voltage becomes reference voltage.
The "Charge Sequence" may shorter the time for power up initialization.
Charge Sequence: To set mode switch from standby to active during power up initialization, activate rapid
charge circuit for stabilizing the output voltage.
NJM2776
-7-
■
TYPICAL CHARACTERISTICS
0
500
1000
1500
2000
0123456
Operating Current vs. Operating Voltage
Op erating Current [µA]
Operating Voltage(V
+
1) [V]
V
+
2=1.2V, Ta=25
o
C, Active
V
+
2
V
+
1
0
200
400
600
800
1000
0 0 .5 1 1.5 2 2.5
Operating Current vs. Operating Voltage
Operating Current [µA]
Oper ating Voltage (V+2) [V]
V+1=2.3V, Ta=25oC, Active
V+2
V+1
0
10
20
30
40
50
0123456
Operating Current vs. Operating Voltage
Op erating Current [µA]
Operating Voltage (V+1) [V]
V+2=1.2V, Ta=25oC, Standby
V+2
V+1
0
5
10
15
20
25
00.511.522.5
Operating Current vs. Operating Voltage
Op erating Current [µA]
Oper ating Voltage (V+2) [V]
V+1=2.3V, Ta=25oC, Standby
V+2
V+1
0
100
200
300
400
500
600
-50 0 50 100 150
Operating Current vs. Temperature
Op erating Current [µA]
Ta [oC]
V+1=2.3V, V+2=1.2V, Active
V+2
V+1
0
5
10
15
20
25
30
35
40
-50 0 50 100 150
Operating Current vs. Temperature
Operating Current [mA]
Ta [oC]
V+1=2.3V, V+2=1.2V, Standby
V
+
1
V
+
2
NJM2776
- 8 -
■
TYPICAL CHARACTERISTICS
0
0.2
0.4
0.6
0.8
1
0 0.5 1 1.5 2 2.5
Reference Voltage vs. Operating Voltage
Reference Voltage [V]
Operating Voltage (V
+
2) [V]
V
+
1=2.3V, Ta=25
o
C
0
100
200
300
400
500
600
700
-50 0 50 100 150
Reference Voltage vs. Temperature
Reference Voltage [mV]
Ta [
o
C]
V
+
1=2.3V, V
+
2=1.2V
0.01
0.1
1
10
0.001 0.01 0.1 1 10
Total Harmonic Distortion vs. Output Power
THD+N [%]
Output Power [mW]
Ta=-20
o
C
V
+
1=2.3V, V
+
2=1.2V, f=1KHz, RL=16Ω, BW=400Hz-30kHz
Ta=25
o
C
Ta=75
o
C
0
2
4
6
8
10
12
14
0.5 1 1.5 2 2.5 3
Output Power vs. Operating Voltage
Output Power [mW]
Operating Voltage (V
+
2) [V]
V
+
1=2.3V, f=1kHz, THD=10%, RL=16Ω, BW=400-30kHz
Ta=25
o
C
Ta=75
o
C
Ta=-20
o
C
0
10
20
30
40
50
0246810
Power Dissipation vs. Output Power
Op er ating Current [mW]
Output Power [mW/ch]
V+1=2.3V, V+2=1.2V, f=1kHz, RL=16Ω, BW=30kHz, Ta=25oC
THD=10%
0.01
0.1
1
10
0.001 0.01 0.1 1 10
Total Harmonic Distortion vs. Output Power
THD+N [%]
Output Power [mW]
f=10kHz
V
+
1=2.3V, V
+
2=1.2V, RL=16Ω, Ta=25
o
C
f=1kHz
f=100Hz
BW
f=10kHz:400-80kHz
f= 1kHz:400-80kHz
f=100Hz: 10-30kHz
NJM2776
-9-
■
TYPICAL CHARACTERISTICS
-110
-100
-90
-80
-70
-60
-50 0 50 100 150
Output Noise Voltage vs. Temperature
Output Noise Voltage [dBV]
Ta [oC]
V+1=2.3V, V+2=1.2V, RL=16Ω, Rg=600Ω, A-Weighted
0
20
40
60
80
100
0.01 0.1 1 10
Channel Separation vs. Frequency
Channel Separation [dB]
Freque ncy [kHz]
V
+
1=2.3V, V
+
2=1.2V, Vin=-30dBV, RL=16 Ω, Ta=25
o
C
-110
-100
-90
-80
-70
-60
-50
-40
-30
0.01 0.1 1 10 100
Mute Level vs. Frequency
Mute Level [dB]
Frequency [kHz]
V
+
1=2.3V, V
+
2=1.2V, Vin=-30dBV=0dB, RL=16 Ω, Ta=25
o
C
1kHz Band pass, STANDBY
-110
-100
-90
-80
-70
-60
-50
-40
-30
-50 0 50 100 150
Mute Level vs. Temperature
Mute Level [dB]
Ta [
o
C]
V
+
1=2.3V, V
+
2=1.2V, Vin=-30dBV=0dB, f=1KHz, RL=16 Ω
1kHz Band pass STANDBY
0
20
40
60
80
100
0.01 0.1 1 10 100
PSRR vs. frequency (V
+
1)
PSRR [dB]
Frequency [kHz]
V
+
1=1.8V+0.1Vrms, V
+
2=0.9V, R g=600Ω, RL=16Ω, Ta=25
o
C
0
20
40
60
80
100
0.01 0.1 1 10 100
PSRR vs. frequency (V
+
2)
PSRR [dB]
Frequency [kHz]
V
+
1=1.8V, V
+
2=0.9V+0.1Vrms, Rg=600Ω, R L=16Ω, Ta=25
o
C
NJM2776
- 10 -
■
TYPICAL CHARACTERISTICS
[CAUTION]
The specifications on this databook are only
given for information , without any guarantee
as regards either mistakes or omissions. The
application circuits in this databook are
described only to show representative usages
of the product and not intended for the
guarantee or permission of any right including
the industrial rights.
-120
-100
-80
-60
-40
-20
0
20
-0.5 0 0.5 1 1.5 2
Gain vs. STANDBY Control Voltage
Gain [dB]
STANDBY Control Voltage [V]
V+1=2.3V, V+2=1.2V, Vin=-30dBV, f=1kHz, RL=16 Ω
Ta=-20oC
Ta=25oC
Ta=75oC
