NJM2768B
-1-
HEADPHONE AMPLIFIER for CD-ROM
GENERAL DESCRIPTIO N
PACKAGE OUTLINE
The NJM2768B is a headphone am plifier des igned f or CD-
ROM.
It includes 0dB closed loop gain and mute circuit, requires
few external component.
The NJM2768B realizes very low turn-noise at mute mode.
It is suitable for CD-ROM, and other general audio
headphone amplifier application.
FEATURES
Operating Voltage 2.8 to 5.5V
Operating Current 2mA typ. at V
+
=5V
Fixed Gain 0dB typ.
Stereo Headphone Output
Internal Mute Circuit
Bipolar Technology
Package Outline DMP8
MSOP8(TVSP8)*
*MEET JEDEC MO-187-DA / THIN TYPE
PIN CONFIGURA TION
1
2
3
4
8
7
6
5
BLOCK DIAGRAM
1 2 3 4
8 7 6 5
BIAS
MUTE
PIN FUNCTION
1.OUT1
2.MUTE
3.IN1
4.GND
5.IN2
6.BIAS
7.OUT2
8.V
+
NJM2768BRB1
MSOP8(TVSP8)
NJM2768BM
(DMP8)
NJM2768B
-2-
ABSOL UTE MAXIMUM RATINGS
(Ta=25°C)
PARAMETER SYMBOL RATINGS UNIT
Supply Voltage V
+
+7 V
Power Dissipation P
D
(DMP8) 375
750 (note)
(MSOP8(TVSP8))320 mW
Operating Temperature Range Topr -40 to +85 °C
Storage Temperature Range Tstg -50 to +150 °C
(note) At on PC board
ELECTRICAL CHARACTERI STICS
(V
+
=5.0V,Vin=0dBV,f=1kHz,R
L
=32Ω,Ta=25°C unless otherwise specified)
PARAMETER SYMBOL TEST CONDITIONS MIN. TYP. MAX. UNIT
Operating Voltage V
+
2.8 5.0 5.5 V
Operating Current I
CC
No Signal - 2.0 4.0 mA
Reference Voltage Vref No Signal - 2.1 - V
Closed Loop Gain G
V
-1 0 1 dB
Channel Balance ∆G
V
-0.5 0 +0.5 dB
Output Power P
O
1 R
L
=32Ω, THD=0.1% 30 50 - mW
P
O
2 R
L
=16Ω, THD=0.1% 40 100 - mW
Total Harmonic Distortion THD - 0.02 0.1 %
Output Noise Voltage Vno Rg=0Ω, A-Weighted - -104
(6.3) -94
(20) dBV
(µVrms)
Mute Attenuation ATT Vo/Vin - -80 -70 dB
Channel Separation CS
90 110 - dB
Ripple Rejection Ratio RR
Vripple=-20dBV, Rg=0Ω - 70 - dB
Input Voltage H-level V
IH
2.0 - V
+
V
Input Voltage L-level V
IL
0.0 - 0.3 V
CONTROL PI N INFORMATI O N
PARAMETER CONTROL SIGNAL OPERATING CONDITION
MUTE ON L NON-SIGNAL
MUTE OFF H OUTPUT SIGNAL
NJM2768B
-3-
TERMINAL DESCRIPTION
PIN
NO. SYMBOL FUNCTION EQUIVALENT CIRCUIT
TERMINAL
VOLTAGE
1
7 OUT1
OUT2 OUTPUT1
OUTPUT2
(V
+
-1V
BE
)/2
2 MUTE MUTE CONTROL
-
3
5 IN1
IN2 INPUT1
INPUT2
(V
+
-1V
BE
)/2
6 BIAS REFERENCE VOLTAGE
STABILIIZED CAPACITOR
CONNECT TERMINAL
(V
+
-1V
BE
)/2
350k
10uA
50k
50k
BIAS
50k
50k
FB
NJM2768B
-4-
TYPICAL APPLICATION
16
Ω
/32
Ω
GND
IN1
MUTEOUT1
OUT2
mute
BIAS
1
2
8765
1 2 34
BIAS IN2
V
+
1 F
16
Ω
/32
Ω
SPEAKER
H: SPEAKER Active
L: SPEAKER Mute
MUTE
100
µ
F
+
V
47
µ
F
1
µ
F
100k
Ω
100
µ
F
SPEAKER
NJM2768B
-5-
TYPI CAL CHARA CTERISTICS
0
0.5
1
1.5
2
2.5
3
3.5
4
0123456
Oprating Current vs. Operating Voltage
Op erati ng Curren t (mA )
Op erating Voltage (V)
(MUTE=V+)
0
0.5
1
1.5
2
2.5
3
3.5
4
-40-200 20406080100120
O perating Cur rent v s. A mbi ent T emperature
Op erati ng Curren t (mA )
Ambient Temperature (
o
C)
V
+
=5V
V
+
=2.8V
0
0.5
1
1.5
2
2.5
3
0123456
Reference Voltage vs. Operating Voltage
Reference Voltage (V)
Op erating Voltage (V)
0
0.5
1
1.5
2
2.5
3
-40-200 20406080100120
Refe re nce Voltage vs. Ambient Temper ature
Reference Voltage (V)
Ambient Temperature (
o
C)
V
+
=5V
V
+
=2.8V
0
50
100
150
200
250
300
350
400
0 20406080100120
Po w er Dis s ip ation vs.Output P ower
Power Dissipation (m W)
Output Power (mW)
THD=10%
(V+=5V,f=1KHz)
RL=32Ω
RL=16Ω
0
20
40
60
80
100
120
0 5 10 15 20 25
Pow er Dissipation vs.Output Power
Power Dissipation (m W)
Output Power (mW )
THD=10%
(V+=2.8V,f=1KHz)
RL=32Ω
RL=16Ω
0
50
100
150
200
250
300
350
400
0 20406080100120
Power Dissipation vs. Output Power
Power Dis sipation (mW)
Output Power (m W)
THD=10%
(V+=5V,f=1KHz)
RL=16
RL=32
0
20
40
60
80
100
120
0 5 10 15 20 25
Power Dissipation vs. Output Power
Power Dis sipation (mW)
Output Power (m W)
THD=10%
(V+=2.8V,f=1KHz)
RL=16
RL=32
NJM2768B
-6-
-100
-90
-80
-70
-60
-50
10 100 1K 10K
Mute Level vs . Frequency
Mute Level (dB)
Frequency (Hz)
(V+=5V,Vin=-6dBV,RL=32Ω)
Ta=-40
o
C
Ta=25
o
C
Ta=85
o
C
0.01
0.1
1
10
0.001 0.01 0.1
THD+N vs. Output Power
THD+N (%)
Output Power (mW)
(V+=5V,f=1KHz,RL=32Ω)
Ta=-40
o
C
Ta=25
o
C
Ta=85
o
C
0.01
0.1
1
10
0.001 0.01 0.1
THD+ N v s. Output Power
THD+N (%)
Output Power (mW)
(V+=5V,f=1KHz,RL=16Ω)
Ta=85
o
C
Ta=-40
o
C
Ta=25
o
C
0.01
0.1
1
10
110100
THD+N vs. Output Power
THD+N (%)
Output Power (mW)
(V+=2.8V,f=1KHz,RL=32Ω)
Ta=-40
o
C
Ta=25
o
C
Ta=85
o
C
0.01
0.1
1
10
110100
THD+ N v s. Output Power
THD+N (%)
Output Power (mW)
(V+=2.8V,f=1KHz,RL=16Ω)
Ta=85
o
C
Ta=-40
o
C
Ta=25
o
C
-110
-105
-100
-95
-90
-40 -20 0 20 40 60 80 100 120
O ut put Noise Voltage vs. Am bient Tem perature
Outp ut Noise Voltage (dBV)
Ambient Temperature (
o
C)
(RL=32Ω,A-Weigthed)
V
+
=5V
V
+
=2.8V
NJM2768B
-7-
[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.
40
50
60
70
80
90
100
110
120
10 100 1000 10
4
Channel Separation vs. Frequency
Channel Separation (dB)
Frequency (Hz)
(V+=5V,f=1KHz,RL=32Ω)
0
20
40
60
80
100
0.01 0.1 1 10
Ripple Rejection Ratio vs. Frequen cy
Ripple Rejection Rati o (dB)
Frequency (Hz)
(Vripple=-20dBV,RL=32Ω)
V
+
=5V
V
+
=2.8V
-100
-80
-60
-40
-20
0
20
00.511.5
Volt age G ain v s Mute Contr ol Vol tage
Volta ge G ain (dB)
MUTE Covtrol Voltage (V)
(V+=5V,f=1KHz,Vin=-6dBV)
Ta=-40
o
C
Ta=25
o
C
Ta=85
o
C
