NJM2761
-1-
Audio Limiter
■ GENERAL DESCRIPTION
The NJM2761 is an audio limiter for speaker protection.
The limit level is adjustable by external resistor.
It is suitable for PC, potable audio and others.
■ FEATURES
● Wide Operating Voltage +2.7V to +13.0V
● Variable Limit Level by external resistor 0.2 to1V
● Low Output Noise -90dBV max.
● Bipolar Technology
● Package Outline MSOP10 (TVSP10)*
SSOP14
*MEET JEDEC MO-187-DA / THIN TYPE
■ BLOCK DIAGRAM
■
PACKAGE OUTLINE
Vcc
INT SENSE
OUTb
OUTa
INb
INa
Vref
SW
NJM2761RB2
MSOP10 (TVSP10)
NJM2761
V
(SSOP14)
NJM2761
- 2 -
■ PIN CONFIGURATION
MSOP10 (TVSP10)
SSOP14
1. V+
2. OUTa
3. INa
4. INT
5. VREF
6. NC
7. NC
8. NC
9. NC
10. SENCE
11. SW
12. INb
13. OUTb
14. GND
1. V+
2. OUTa
3. INa
4. INT
5. VREF
6. SENCE
7. SW
8. INb
9. OUTb
10. GND
14
13
12
11
10
1
2
3
4
5
6
7
9
8
10
9
8
7
6
1
2
3
4
5
NJM2761
-3-
■ ABSOLUTE MAXIMUM RATING (Ta=25°C)
PARAMETER SYMBOL RATINGS UNIT
Supply Voltage V
+
14 V
Power Dissipation P
D
320(MSOP10 (TVSP10))
300(SSOP14) mW
Operating Temperature Range T
opr
-20 to +75 °C
Storage Temperature Range T
stg
-40 to +125 °C
■ ELECTRICAL CHARACTERISTICS
● POWER SUPPLY (Ta=25°C, V
+
=5V unless otherwise specified)
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Operating Voltage V
+
- 2.7 5.0 13.0 V
Operating Current I
CC
No Signal - 1.5 2.0 mA
Reference Voltage Vref No Signal 2.2 2.5 2.7 V
● AC CHARACTERISTICS
(Ta=25°C, V
+
=5V, V
IN
=1Vrms/f=1kHz, Rsense=20kΩ, BW=400-30kHz unless otherwise specified)
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Limit Level 1 G
LIM1
150 200 250 mVrms
Limit Level 2 G
LIM2
V
+
=13V,Rsense=4kΩ,V
IN
=2Vrms 0.7 1.0 1.3 Vrms
Limit Off G
OFF
SW=2V 0.9 1.0 1.1 Vrms
Output Noise V
NO
R
S
=0Ω, A-weighting,
- -100
(10)
-90
(31.6)
dBV
(µVrms)
Total Harmonic Distortion THD+N - - 1 %
Cross Talk CT - - -70 dB
Ripple Rejection RR V
ripple
=100mVrms, f=1kHz - - -70
(316)
dBV
(µVrms)
● CONTROL CHARACTERISTICS (Ta=25°C, V
+
=5V unless otherwise specified)
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Low Level Input Voltage V
IL
- - - 0.5 V
High Level Input Voltage V
IH
- 2.0 - - V
■ CONTROL TERMINAL EXPLANATION
SW(MSOP10 (TVSP10)):7pin, SSOP14:11pin)
MODE STATUS NOTE
Limiter ON L Limiter is active.
Limiter OFF H Limiter is not active.
NJM2761
- 4 -
■ TERMINAL DESCRIPTION
No
,
MSOP10(SSOP14)
SYMBOL FUNCTION EQUIVALENT CIRCUIT VOLTAGE
1 V+ Power Supply Terminal
-
2
9(13)
OUTa
OUTb
Ach Output Terminal
Bch Output Terminal
V+/2
3
8(12)
INa
INb
Ach Input Terminal
Bch Input Terminal
V+/2
4 INT
Smoothing Capacitor
Connection
Terminal
0.7V
5 VREFIN
Reference Voltage Stabilizing
Capacitor Connection Terminal
V+/2
OUTa
OUTb
100
INa
INb
48k
96k
1k
INT 400
VREFIN
300k
300k
300k
NJM2761
-5-
■ TERMINAL DESCRIPTION
No.
MSOP10(SSOP14)
SYMBOL FUNCTION EQUIVALENT CIRCUIT VOLTAGE
6(10) SENSE
Resister Connection Terminal
for Limit Level Setting
0V
7(11) SW Limiter ON/OFF Switch
-
10(14) GND Ground Terminal
-
SW
150k
270k
SENSE
12k
NJM2761
- 6 -
14
1414
14
13
1313
13
12
1212
12
11
1111
11
10
1010
10
OUTa
OUTaOUTa
OUTa
IN T
IN TIN T
IN T
IN a
IN aIN a
IN a
GND
GNDGND
GND
VREF
VREFVREF
VREF
SENSE
SENSESENSE
SENSE
SW
SWSW
SW
IN b
IN bIN b
IN b
OUTb
OUTbOUTb
OUTb
0.22uF
V
VV
V
+
++
+
0 .2 2 u F
1uF
0 .2 2 u F
0 .2 2 u F
1 u F
1
11
1
2
22
2
3
33
3
4
44
4
5
55
5
V+
V+V+
V+
R
RR
RSENSE
SENSESENSE
SENSE
0 .0 2 2 u F
6
66
6
7
77
7
9
99
9
8
88
8
NC
NCNC
NC
NC
NCNC
NC
■
APPLICATION CIRCUIT
MSOP10 (TVSP10)
SSOP14
* The limit level is twice as much as set point when a signal is input into a either one channel of Ach or
Bch.
* For the above reason, monaural signal should input both INa and INb.
R
SENSE
=4000/Vlim[Ohm]
Vlim: Limit level(Vrms)
Limit range: 200mVrms to 1Vrms (20k to 4kOhm)
10
9
8
7
6
OUTa
INT
INa
GN
D
VREF SENS
E
S
W
INb
OUTb
0.22µ
F
V+
0.22µF
1µF
0.22µF
0.22µF
1µF
1
2
3
4
5
V+
R
SENSE
0.022µF
NJM2761
-7-
■ TYPICAL CHARACTERISTICS
0
0.5
1
1.5
2
051015
V
+
- Icc
Vcc[V]
V
+
=5V,No-Signal,Limiter=ON,Rsense=20k Ω
Icc[mA]
0
0.5
1
1.5
2
-20 0 20 40 60 80
Icc-Temperature
Icc[mA]
Temperature [C
o
]
V
+
=5V,No-Signal,Limiter=ON,Rsense=20k Ω
0.01
0.1
1
0.01 0.1 1
Limit Response-V
+
Output[Vrms]
Input[Vrms]
Vin=0dBV,Limiter=ON,Rsense=20k Ω
V
+
=13.0V
V
+
=2.7V
V
+
=5.0V
0.01
0.1
1
10
0.0001 0.001 0.01 0.1 1
Vom
THD[%]
Input[Vrms]
f=1kHz,Limiter=OFF,Rsense=20k Ω
V
+
=2.7V
V
+
=5.0V
V
+
=13.0V
0.01
0.1
1
0.01 0.1 1
Limit Response-Rsense
Output [Vrms]
Input[Vrms]
V
+
=5V,f=1kHz,Limiter=ON
Rsense=4k
Rsense=8k
Rsense=20k
0.01
0.1
1
0.01 0.1 1
Limit Response-Temperature
Output [Vrms]
Input[Vrms]
-20C
o
25C
o
75C
o
V
+
=5V,Vin=0dBV,Limiter=ON,Rsense=20k
Ω
NJM2761
- 8 -
■ 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.
-100
-80
-60
-40
-20
0
100 1000 10000
Ripple Rejection
Ripple[dBV]
Frequency[Hz]
V
+
=5V,Vripple=100mVrms,Limiter=ON
-20C
o
25C
o
75C
o
0.01
0.1
1
10
0.001 0.01 0.1 1
THD-Vcc
THD[%]
Input[Vrms]
f=1kHz,Limiter=ON,Rsense=20k
Ω
V
+
=2.7V
V
+
=5.0V
V
+
=13.0V
0.01
0.1
1
10
0.001 0.01 0.1 1
THD-Temperature
THD[%]
Input[Vrms]
V
+
=5V,Vin=0dBV,Limiter=ON,Rsense=20k
Ω
-20C
o
25C
o
75C
o
-100
-95
-90
-85
-80
-75
-70
-65
-60
100 1000 10000
Cross Talk
Cross Talk[dB]
Frequency[Hz]
V
+
=5V,Vin=0dBV,Limiter=ON,Rsense=20k
Ω
-20C
o
25C
o
75C
o