NJM2794
– 1 –
Ground Noise Isolation Amplifier
■ GENERAL DESCRIPTION
The NJM2794 is a ground noise isolation amplifier
designed for car audio system. It contains dual channel
differential amplifier.
It is developed for those car audio applications where long
connections between head unit and other components are
necessary and ground noise has to be eliminated.
■ FEATURES
● Dual Channel Differential Amplifier
● Operating Voltage 4.3 to 13V
● Operating Current 14mA typ.
● Common mode rejection ratio CMRR=60dB typ.
● Maximum Output Voltage 2Vrms min., @ THD=0.1%
● Supply Voltage Rejection Ratio 60dB typ.
● Total Harmonic Distortion 0.002% typ.
● Noise Output Voltage 1.3µVrms typ.
● Bipolar Technology
● Package Outline MSOP10 (TVSP10)*
SSOP14
*MEET JEDEC MO-187-DA / THIN TYPE
■ BLOCK DIAGRAM
■PACKAGE OUTLINE
NJM2794V
(SSOP14)
NJM2794RB2
MSOP10 (TVSP10)
OUT2
OUT1
IN1-
IN1+
IN2+
IN2-
Vref
GND
V+
NJM2794
– 2 –
■ PIN CONFIGURATION
MSOP10(TVSP10)
SSOP14
110
65
No. Symbol Function
1 OUT1 Output1
2 GND Ground
3 Vref Reference Voltage
4 V+ Power Supply
5 OUT2 Output2
6 IN2+ +Input2
7 IN2- -Input2
8 NC No Connect
9 IN1- -Input1
10 IN1+ +Input1
114
87
No. Symbol Function
1 OUT1 Output1
2 NC No Connect
3 GND Ground
4 Vref Reference Voltage
5 V+ Power Supply
6 NC No Connect
7 OUT2 Output2
8 IN2+ +Input2
9 NC No Connect
10 IN2- -Input2
11 NC No Connect
12 IN1- -Input1
13 NC No Connect
14 IN1+ +Input1
NJM2794
– 3 –
■ ABSOLUTE MAXIMUM RANGES (Ta=25°C)
PARAMETER SYMBOL RANGE UNIT
Supply Voltage V
+
+15 V
Maximum Input Voltage V
IM
0 to V
+
(✴)
V
Power Dissipation P
D
MSOP10(TVSP10) : 530*
SSOP14 : 550*
NOTE: EIA/JEDEC STANDARD Test board (76.2x114.3x1.6mm, 2layer, FR-4) mounting
mW
Operating Temperature Topr -40 to +85 °C
Storage Temperature Tstg -40 to +150 °C
(✴) For the maximum input voltage less than 0 toV
+
■ ELECTRICAL CHARACTERRISTIC (V
+
=9V,Ta=25°C)
PARAMETER
SYMBOL
TEST CONDITION MIN. TYP. MAX. UNIT
DC CHARACTERRISTIC
Operating Voltage
V
+
4.3 9 13 V
Operating Current
I
CC
No Signal - 14 20 mA
Reference Voltage
V
REF
3.8 4.3 4.8 V
AC CHARACTERRISTIC (Non-inverting circuit, f=1kHz, Vin=1Vrms, R
g
=0Ω, R
L
=10kΩ unless otherwise specified
)
Voltage Gain
Gv
-1.0 0.0 +1.0 dB
Channel Separation
CS f=1kHz
90 110 - dB
Channel Balance
BAL
- - 0.5 dB
Roll-off High Frequency
f
RH
-1dB 100 - - kHz
Input Resistance
R
IN
85 105 125 kΩ
Output Resistance
R
OUT
- 90 - Ω
Maximum Output Voltage 1
V
OM1
THD=0.1%, f = 1kHz 2 2.5 - Vrms
Maximum Output Voltage 2
V
OM2
THD=0.1%, f = 1kHz, V
+
=8V 1.7 2.1 - Vrms
Maximum Output Voltage 3
V
OM3
Inverting,
THD=0.1%, f = 1kHz - 2.5 - Vrms
Maximum Output Voltage 4
V
OM4
Inverting,
THD=0.1%, f = 1kHz, V
+
=8V - 2.1 - Vrms
Noise Output Voltage
V
NO
Rg=600Ω, A-weighted - 1.3 2.5 µVrms
Total Harmonic Distortion
THD
f=1kHz , V
O
=1Vrms,
BW=400Hz to 30kHz - 0.002 0.01 %
Common Mode
Rejection Ratio
CMRR
50 60 - dB
Common Mode
Input Voltage
Vicm
CMRR=50dB - 2 - Vrms
Supply Voltage
Rejection Ratio
SVR
f=100Hz , V
ripple
=100mVrms 55 65 - dB
NJM2794
– 4 –
■
TERMINAL DESCRIPTION
PIN NO.
TVSP
10
SSOP
14
SYMBOL FUNCTION EQUIVALENT CIRCUIT
TERMINAL
DC
VOLTAGE
1
5
1
7
OUT1
OUT2
Output1
Output2
V
+
x0.48 [V]
6
7
9
10
8
10
12
14
IN2+
IN2-
IN1-
IN1+
+Input2
-Input2
-Input1
+Input1
V
+
x0.48 [V]
3 4 Vref Reference Voltage
V
+
x0.48 [V]
100Ω
FB
V+V+
100Ω
240kΩ
260kΩ
V+ V+ V+
50Ω
105kΩ
Vre f
NJM2794
– 5 –
■ APPLICATION CIRCUIT
● MSOP10(TVSP10) : NJM2794RB2
● SSOP14 : NJM2794V
OUT1
OUT2
IN1+
IN2+
1
2
3
4
5
10
8
7
6
+
+
+
+
+
+
10μF
3.3μF
3.3μF0.33μF
0.33μF
OUT1IN1+
IN2+
OUT2
V+
V+
22μF
Vref
GND IN1-
9
+
0.33μF
IN1-
IN2-
+
0.33μF
IN2-
NC
NC
2
3
4
5
6
13
11
10
9
+
+
10μF
NC NC
NC
V+
V+
22μF
Vref
GND IN1-
12
+
0.33μF
IN1-
IN2-
+
0.33μF
IN2-
NC
OUT1
1
+
3.3μF
OUT1IN1+
14
+
0.33μF
IN1+
OUT2 IN2+
7 8
+
+
3.3μF0.33μF
IN2+
OUT2
NJM2794
– 6 –
■ APPLICATION BLOCK DIAGRAM
(1) Non-inverting line input
IC GND
IN+
IN-
NJM2794
OUT
Vref
V
N
IC GND
IN+
IN-
NJM2794
OUT
Vref
V
N
IC GND
IN-
IN+
NJM2794
OUT
Vref
V
N
IC GND
IN-
IN+
NJM2794
OUT
Vref
V
N
(2) Inverting line input
(3) Non-inverting line output
(4) Inverting line output
NJM2794
– 7 –
■ TYPICAL CHARACTERISTICS
Operating Current vs. Ambient Temperature
V+=9V
0
5
10
15
20
25
30
-50 -25 0 25 50 75 100 125 150
Ambient Temperature [oC]
Operationg Current [mA]
Reference Voltage vs. Ambient Temperature
V+=9V
0
3
6
9
12
15
-50 -25 0 25 50 75 100 125 150
Ambient Temparature [oC]
Reference Voltage [V]
Operating Current vs. Operating Voltage
0
5
10
15
20
25
30
03691215
Operating Voltage [V]
Operating Current [mA]
25oCTa=85oC
-40oC
Reference Voltage vs. Operating Voltage
0
3
6
9
12
15
03691215
Operating Voltage [V]
Reference Voltage [V]
Ta=85,25,-40oC
Noise Output Voltage vs. Ambient Temperature
V+=9V, Rg=600Ω, A-Weighted
-140
-120
-100
-80
-60
-40
-20
0
-50 -25 0 25 50 75 100 125 150
Ambient Temperature [
o
C]
Noise Output Voltage [dBV]
Noise Output Voltage vs. Signal Source Resistance
V+=9V, Ta=25
o
C, A-Weighted
-120
-100
-80
-60
-40
-20
0
0.01 0.1 1 10 100
Signal Source Resistance [kΩ]
Noise Output Voltage [dBV]
NJM2794
– 8 –
■ TYPICAL CHARACTERISTICS
Channel Separation vs. Ambient Temperature
V+=9V, Rg=600Ω, Vin=1Vrms, BW=400Hz-30kHz
-120
-100
-80
-60
-40
-20
0
-50 -25 0 25 50 75 100 125 150
Ambient Temperature [
o
C]
Channel Separation [dB]
IN1+ -> OUT2
THD+N vs. Output Voltage
V+=9V, f=1kHz, Non-Inverting Circuit
0.001
0.01
0.1
1
0.01 0.1 1 10
Output Voltage [Vrms]
THD+N [%]
Ta=25,85
o
C
Ta=-40
o
C
THD+N vs. Output Voltage
V+=9V, f=1kHz, Inverting Circuit
0.001
0.01
0.1
1
0.01 0.1 1 10
Output Voltage [Vrms]
THD+N [%]
Ta=-40,25,85
o
C
Channel Separation vs. Frequency
V+=9V, Rg=600Ω, Vin=1Vrms, BW=10Hz-30kHz
-120
-100
-80
-60
-40
-20
0
10 100 1000 10000 100000
Frequency [Hz]
Channel Separation [dB]
IN2+ -> OUT1
IN1+ -> OUT2
THD+N vs. Output Voltage
V+=8V, f=1kHz, Non-Inverting Circuit
0.001
0.01
0.1
1
0.01 0.1 1 10
Output Voltage [Vrms]
THD+N [%]
Ta=25,85
o
C
Ta=-40
o
C
THD+N vs. Output Voltage
V+=8V, f=1kHz, Inverting Circuit
0.001
0.01
0.1
1
0.01 0.1 1 10
Output Voltage [Vrms]
THD+N [%]
Ta=-40,25,85
o
C
NJM2794
– 9 –
■ TYPICAL CHARACTERISTICS
THD+N vs. Output Voltage
V+=9V, Ta=25
o
C, Inverting Circuit
0.001
0.01
0.1
1
0.01 0.1 1 10
Output Voltage [Vrms]
THD+N [%]
f=100Hz, 1kHz,10kHz
THD+N vs. Output Voltage
V+=9V, Ta=25
o
C, Non-Inverting Circuit
0.001
0.01
0.1
1
0.01 0.1 1 10
Output Voltage [Vrms]
THD+N [%]
f=100Hz, 10kHz
f=1kHz
THD+N vs. Output Voltage
V+=9V, Vin=1Vrms, BW=22Hz-80kHz,
Non-Inverting Circuit
0.001
0.01
0.1
1
10 100 1000 10000 100000
Frequency [Hz]
THD+N [%]
Ta=-40,25,85
o
C
THD+N vs. Output Voltage
V+=9V, Vin=1Vrms, BW=22Hz-80kHz,
Inverting Circuit
0.001
0.01
0.1
1
10 100 1000 10000 100000
Frequency [Hz]
THD+N [%]
Ta=-40,25,85
o
C
Maximum Output Voltage vs. Operating Voltage
f=1kHz, THD=0.1%, Non-Inverting Circuit
0
1
2
3
4
03691215
Operating Voltage [V]
Maximum Output Voltage [Vrms]
Ta=-40,25,85
o
C
Maximum Output Voltage vs. Operating Voltage
f=1kHz, THD=0.1%, Inverting Circuit
0
1
2
3
4
03691215
Operating Voltage [V]
Maximum Output Voltage [Vrms]
Ta=-40,25,85
o
C
NJM2794
– 10 –
■ TYPICAL CHARACTERISTICS
Voltage Gain vs. Frequency
V+=9V, Vin =1 Vrm s , Ta =25
o
C
-10
-8
-6
-4
-2
0
2
4
6
8
10
10 100 1000 10000 100000
Frequency [Hz]
Voltage Gain [dB]
Non-Inverting Circuit, Inverting Circuit
Maximum Output Voltage vs. Load Resistance
V+=9V, f=1kHz, Ta=25
o
C, BW=400 - 30kHz
0
1
2
3
4
5
0.1 1 10 100
Load Resistance [kΩ]
Maximum Output Voltage [Vrms]
V+=13V
9V
4.3V
THD=0.1%
Supply Voltage Rejection Ratio
vs. Frequency
V+=9V, Vripple=100mV, Rg=600Ω, Ta=25℃
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10 100 1000 10000 100000
Frequency [Hz]
Supply Voltage Rejection Ratio [dB]
C
ref
=4.7µF
C
ref
=22µF
C
ref
=10µF
Reference Voltage Turn-on behaviour
V+=9V, Ta=25℃
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
012345678910
tim e [s ec]
Reference Voltage [V]
C
ref
=4.7µF
C
ref
=22µF
C
ref
=10µF
Supply Voltage Rejection Ratio
vs. Operating Voltage
Vripple=100mV, f=100Hz, Rg=600Ω, Ta=25
o
C
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
03691215
Operating Voltage [V]
Supply Voltage Rejection Ratio
[dB]
Supply Voltage Rejection Ratio
vs. Signal Source Resistance
V+=9V, Vrippple=100mV, f=100Hz, Ta=25
o
C
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
0.1 1 10 100
Signal Source Resistance [kΩ]
Supply Voltage Rejection Ratio [dB]
NJM2794
– 11 –
■ 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.
Common Mode Rejection Ratio vs. Input Voltage
V+=9V, f=1kHz, Ta=25
o
C, BW=400 - 30kHz
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
0.001 0.01 0.1 1 10
Input Voltage [Vrms]
Common Mode Rejection Ratio [dB]
Ta=-40
o
C
85
o
C
25
o
C
Common Mode Rejection Ratio vs. Frequency
V+=9V, Vin =1 Vrm s
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10 100 1000 10000 100000
Frequency [Hz]
Common Mode Rejection Ratio [dB]
Ta=-40
o
C
25
o
C
Ta=85
o
C
