NJRC NJW1124V

NJW1124
Voice Switched Speakerphone circuit
! GENERAL DESCRIPTION
! PACKAGE OUTLINE
The NJW1124 is a Voice Switched Speakerphone Circuit.
NJW1124 includes all of functions processing a high quality hands–free
speakerphone system, such as the necessary amplifiers ( Microphone ,
Receive ,Line), attenuators, level detectors functions.
All external capacitors are sufficient small so that ceramic capacitors are
applied.
NJW1124V
! APPLICATION
•Video Door Phone
•Conference System
•Wireless Application
•Security System
! FEATURES
• Operating voltage range
• Force to Receive, Transmit, or Idle modes
• Mode –watching monitor
• Attenuator gain range between Transmit and Receive
• Microphone amplifier with mute function
• Background noise monitor for each path
• Volume control range
• 4-point signal sensing
• Microphone and Receive Amplifiers pinned out for flexibility
• Package Outline
2.9 to 4.5V
52dB
40dB
SSOP32
! BLOCK DIAGRAM
C6 R2
100n 5.1k
R3
51k
C8
100n
C7
100n
C9
R6
100n 5.1k
R7
51k
Microphone
R4
51k
MCO
MCI
R5
10k
TLI2
TLI1
Line Out
C10
TXO
LII
LiO-
LiO+
V+
V
+
R1
300k
C1
1µ
µ
C3
470n
C4
470n
C2
1u
-1
Tx Attenuator
Mic
Amplifier
VREF
Line Amplifier
Monitor
MUT
TLO2
C5
1µ
µ
CT
Level
Detector
+
V
RLO2
RTSW
Background
NoiseMonitor
CPT
Attenuator
Control
Background
NoiseMonitor
CPR
Level
Detector
TLO1
RLO1
C23
1µ
µ
C11
1µ
µ
V+
VREF
VREF
BIAS
Rx Attenuator
RXO RLI2
R10
15k
5.0V
+
C16
10µ
µ
C15
1µ
µ
C21
470n
GND
VREF
1.2µ
µA
V+
C20
470n
Receive
Amplifier
IC1
NJW1124
VREF2
C22
1µ
µ
C17
100n
C13
R11
10k
VLC
R12
51k
RVLC
RLI1 FO
C18
100n
R13
5.1k
FI
R14
5.1k
C19
100n
Recive In
1µ
Speaker
IC2
NJU7084
Power Amplifier
C14 1 µ
R9
22k
R8
11k
C12
100n
–1–
NJW1124
!PIN CONFIGURATION
32
2
31
3
30
NJW1124
1
4
5
6
7
8
9
10
11
12
13
–2–
29
28
27
26
25
24
23
22
21
20
14
19
15
18
16
17
1
2
3
4
5
6
7
8
9
10
11
12
13
14
VREF2
15
16
LIO+
MUT
NC
CPT
TLO2
RLO2
CT
MCI
MCO
TLI2
TLI1
TXO
LII
LIOGND
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
MON
RTSW
VREF
CPR
RLO1
TLO1
VLC
FI
FO
RLI1
RLI2
RXO
NC
NC
NC
V+
NJW1124
! ABSOLUTE MAXIMUM RATING (Ta=25°C)
PARAMETER
SYMBOL
RATING
UNIT
Power Supply Voltage
V+
5.5
V
Power Dissipation
PD
800 (Note1)
mW
Operating Temperature Range
Topr
-40 ~ +85
°C
Storage Temperature Range
Tstg
-40 ~ +125
°C
Maximum Input Voltage
+
VIMAX
0~V
V
(Note1) EIA/JEDEC STANDARD Test board (76.2x114.3x1.6mm, 2layer, FR-4) mounting
(Note2) Don’t apply the input voltage that exceeds supply voltage.
! OPERATING VOLTAGE
PARAMETER
Operating Voltage
SYMBOL
V
+
TEST CONDITION
-
MIN.
TYP.
MAX.
UNIT
2.9
4.0
4.5
V
! ELECTRICAL CHARACTERISTICS (Ta=25°C,V+=4V,MUT=ACTIVE,RTSW=OPEN,RVLC=0Ω,GVM=0dB,ReceiveAmplifierGV=0dB)
PARAMETER
SYMBOL
TEST CONDITION
MIN.
TYP.
MAX.
UNIT
Operating Current 1
ICC1
RX-mode (Receive)
0.7
2.0
4.0
mA
Operating Current 2
ICC2
TX-mode (Transmit)
0.7
2.0
4.0
mA
Operating Current 3
ICC3
Idle-mode
0.7
2.0
4.0
mA
Reference Voltage
VREF
Idle-mode
1.7
2.0
2.3
V
MIN.
TYP.
MAX.
UNIT
3.0
6.0
9.0
dB
-43
-46
-50
dB
●Receive Attenuator (RxIN=100Vrms,Receive Amplifier Gv=0dB)
PARAMETER
SYMBOL
TEST CONDITION
Receive Attenuator Gain 1
GR1
RX-mode (Receive)
Receive Attenuator Gain 2
GR2
TX-mode (Transmit)
Receive Attenuator Gain 3
GR3
Idle-mode (Standby),CPT=CPR=V
-17
-20
-23
dB
Range R to T mode
∆GR
RX-mode – TX-mode
47
52
57
dB
Dynamic DC offset
GRDC
RX-mode – TX-mode (DC)
-50
-
50
mV
Volume control range
GRVR
RX-mode,RVLC=0Ω-100kΩ
30
40
50
dB
-
-
200
µA
MIN.
TYP.
MAX.
UNIT
3.0
6.0
9.0
dB
-43
-46
-50
dB
Maximum DetecterSink Current
IRSINKMAX
+
RLI1,TLI1,Maximum Sink Current
●Transmit Attenuator (TxIN=100Vrms,Mic.amplifier Gv=0dB)
PARAMETER
SYMBOL
TEST CONDITION
Transmit Attenuator Gain 1
GT1
TX-mode (Transmit)
Transmit Attenuator Gain 2
GT2
RX-mode (Receive)
+
Transmit Attenuator Gain 3
GT3
Idle-mode CPT=CPR=V
-17
-20
-23
dB
Range R to T mode
∆GT
TX-mode – RX-mode
47
52
57
dB
Dynamic DC offset
GTDC
TX-mode – RX-mode (DC)
-50
-
50
mV
Volume control range
GTVR
RX-mode,RVLC=0Ω-100kΩ
31
40
46
dB
-
-
200
µA
Maximum DetecterSink Current
IRSINKMAX
RLI1,TLI1,Maximum Sink Current
–3–
NJW1124
●MIC Amplifier (TxIN=1mVrms,Gv=40dB,RL=5.1kΩ)
PARAMETER
SYMBOL
TEST CONDITION
R5=300kΩ,VMOS=VMCI -VMCO
MIN.
TYP.
MAX.
UNIT
-30
0.0
30
mV
-
0.0
-
nA
Output Offset Voltage
VMOS
Input Bias Current
IMBIAS
Voltage Gain 1
GVM1
f=1kHz
-
40
-
dB
Voltage Gain 2
GVM2
f=20kHz
-
38
-
dB
Maximum Output Voltage
VMMAX
THD=1%
0.9
-
-
Vrms
Maximum Output Current
IMOMAX
-
1.5
-
mA
Maximum Attenuation
GMMUTE
70
73
-
dB
MIN.
TYP.
MAX.
UNIT
-30
0.0
30
mV
-
30
-
nA
-
R5=300kΩ
●Receive Amplifier(RxIN=1mVrms,Gv=40dB,RL=5.1kΩ)
PARAMETER
SYMBOL
TEST CONDITION
Output Offset Voltage
VROS
RF=300kΩ,VFOS=VFI -VFO
Input Bias Current
IRBIAS
Voltage Gain 1
GVR1
f=1kHz
-
40
-
dB
Voltage Gain 2
GVR2
f=20kHz
-
38
-
dB
Maximum Output Voltage
VRMAX
THD=1%
0.9
-
-
mVrms
Maximum Output Current
IROMAX
-
-
1.5
-
mA
TEST CONDITION
MIN.
TYP.
MAX.
UNIT
20
0.0
20
mV
-
0.0
-
nA
-
●Line Amplifier (LINEIN=50mVrms, GV=26dB,RL=1.2kΩ)
PARAMETER
SYMBOL
Output Offset Voltage
VLOS
R9=51kΩ
Input Bias Current
ILBIAS
Voltage Gain 1
GVL1
f=1kHz
-
26
-
dB
Voltage Gain 2
GVL2
f=20kHz
-
25
-
dB
Closed Loop Gain
GLC
LIO- to LIO+
-0.5
0
0.5
dB
1.5
-
-
Vrms
-
-
0.5
%
-
-
4.0
-
mA
TEST CONDITION
MIN.
TYP.
MAX.
UNIT
-
-
V
-
Maximum Output Voltage
VLMAX
THD=1%
Total Harmonic Distortion
THDLN
f=1kHz
Maximum Output Current
ILOMAX
●Monitor Terminal (32Pin) Output Voltage
PARAMETER
SYMBOL
+
RX-mode
Rx
-
V -0.3
TX-mode
Tx
-
-
-
0.3
V
+
Idle-mode
Idle
No Signal
-
V /2
-
V
Maximum Output Current
IMON
Rx-mode / Tx-mode
-
1.0
-
mA
–4–
NJW1124
! CONTROL CHARACTERISTICS (MUT)
PARAMETER
SYMBOL
TEST CONDITION
MIN.
TYP.
MAX.
UNIT
Low Level Input Voltage
VIL1
-
-
-
0.3
V
High Level Input Voltage
VIH1
-
1.5
-
-
V
SYMBOL
TEST CONDITION
MIN.
TYP.
MAX.
UNIT
VIL2
-
-
-
0.3
V
V -0.3
-
-
V
! CONTROL CHARACTERISTICS (RTSW)
PARAMETER
Low Level Input Voltage
High Level Input Voltage
VIH2
-
+
! FUNCTION
●MUT (2pin)
INPUT VOLTAGE
STATUS
VIH
MUTE
VIL
ACTIVE
OPERATION
The microphone input is made a mute.
The microphone input is active.
●RTSW (31pin)
INPUT VOLTAGE
VIH
OPEN
STATUS
OPERATION
Receive
Transmit
Force to Receive mode.
Receive mode and Transmit mode are automatically
switched.
Force to Transmit mode.
STATUS
OPERATION
AUTO
VIL
●RVLC (26pin)
IMPEDANCE
0
VolMAM
The Receive attenuator Volume is maximum.
100kΩ
VolMIN
The Receive attenuator Volume is minimum.
–5–
NJW1124
! MEASUREMENT CIRCUIT
S12
R LMH
1
MON
VREF2
S13
V+
OPEN
OPEN
4.7k
R LML
4.7k
MONOUT
32
S6
S2
100
VIH
2
VIL
RTSW
MUT
VIH
100
31
OPEN
VIL
1u
S4
4
1k
V+
CPT
OPEN
100n
100n
1u
300k
TxIN
5
TLO2
6
RLO2
7
CT
S5
0dB 1u
8
3k
40dB
9
100n
MCI
300k
MCOUT
MCO
5.1k
10
TLI2
11
TLI1
5.1k
100n
TxOUT
1u
51k
LINEOUT
30
Vref
CPR
S7
1k
V+
OPEN
RLO1
28
TLO1
27
VLC
26
100n
100n
S8
0ohm
100k
100k
300k
1u 0dB
FI
25
3k
FO
RxIN
40dB
300k
S9
24
FilterOUT
5.1k
RLI1
23
RLI2
22
100n
5.1k
100n
RXO
21
NC
20
TXO
13
LII
14
LIO-
NC
19
15
LIO+
NC
18
16
GND
V+
17
47p
1u
29
12
5.1k
LINEIN
VREF
NC
NJW1124
3
1u
RxOUT
1.2k(R LL)
Icc
V+
1u
–6–
NJW1124
! APPLICATION CIRCUIT
TR1
2.2k
Rx-Mode :V+
Tx-Mode :GND
Idle
:HI-Z
V+
LED1
56k 0.47µ
µ
1
VREF2
2
MUT
3
NC
MON
32
RTSW
31
VREF
30
CPR
29
RLO1
28
TLO1
27
VLC
26
FI
25
1µ
µ
Monitor Out
1µ
µ
4
470n
470n
1u
100n
5.1k
5
TLO2
6
RLO2
7
CT
8
Mic In
CPT
MCI
51k
9
100n
MCO
51k
10
TLI2
10k
TX
OUT
11
100n
100n
12
TLI1
TXO
5.1k
51k
+
13
LII
14
V+
:Recive
GND :Trensmit
Open :Auto
1µ
µ
1µ
µ
470n
470n
100k
5.1k 100n
FO
1µ
µ
15k
V+
24
51k
RLI1
100n
1µ
µ
23
10k
RLI2
1µ
µ
22
100n
RXO
V+
:ACTIVE
GND :Shut Down
Receive In
5.1k
0.1u
21
1
SD
2
SDTC
3
+ IN
OUTB
8
GND
7
V+
6
V+ (2)
10u
20
LIO-
NC
19
4
-IN
OUTA
5
-
15
LIO+
NC
18
16
GND
V+
17
22k
LINE
OUT
-
+
Speaker Out
11k
Receive Out
NC
47p
V+
NJU7084
300k
V+
NJW1124
V+
:MUTE
GND :ACTIVE
V+ (1)
1µ
µ
–7–
NJW1124
! TYPICAL CHARACTERISTICS
Volume control range vs ambient temperature
( VLC=0Ω/100kΩ)
Detector Max Sink Current vs ambient temperature
(TLI1,TLI2,RLI1,RLI2 Max Sink Current)
50.0
700
600
V+=4.0V
500
40.0
Max Sink Current [ ∪A]
Volume Control range [dB]
45.0
V+=4.0V
V+=3.3V
35.0
V+=3.3V
400
300
200
30.0
100
25.0
0
-50
-30
-10
10
30
50
70
90
110
-50
-30
-10
Ambient temperature [℃]
50
70
90
110
70
90
110
10.0
10.0
Tx-Mode
0.0
Tx-Mode
0.0
-10.0
Tx ATT Gain [dB]
-10.0
Tx ATT Gain [dB]
30
Tx ATT Gain vs ambient temperature
(V+=4.0V , Receive Amp Gain = 0dB , VLC=0Ω)
Tx ATT Gain vs ambient temperature
(V+=3.3V , Receive Amp Gain = 0dB , VLC=0Ω)
-20.0
Idle-Mode
-20.0
Idle-Mode
-30.0
-30.0
-40.0
-40.0
Rx-Mode
Rx-Mode
-50.0
-50.0
-50
-30
-10
10
30
50
70
90
-50
110
-30
-10
10
30
50
Ambient temperature [℃]
Ambient temperature [℃]
Monitor Out vs ambient temperature
(V+=4.0V , RLMH=RLML=4.7kΩ)
note : The MONITOR OUT(@Idole-mode) is Hi-Z when there are neither RLMH and RLML.
Monitor Out vs ambient temperature
(V+=3.3V , RLMH=RLML=4.7kΩ)
note : The MONITOR OUT(@Idole-mode) is Hi-Z when there are neither RLMH and RLML.
4.0
4.0
3.5
Rx-Mode
3.5
Rx-Mode
3.0
Monitor output Voltage [V]
3.0
Monitor output Voltage [V]
10
Ambient temperature [℃]
2.5
2.0
Idle-Mode
1.5
2.5
Idle-Mode
2.0
1.5
1.0
1.0
0.5
0.5
Tx-Mode
Tx-Mode
0.0
0.0
-50
-30
-10
10
30
50
Ambient temperature [℃]
–8–
70
90
110
-50
-30
-10
10
30
50
Ambient temperature [℃]
70
90
110
NJW1124
! TYPICAL CHARACTERISTICS
MUTE Pin Voltage vs MUTE ATT Ratio
(V+=4.0V , MICAMP GAIN=40dB, Rf=300kΩ, Ri=3kΩ, A-weighted)
MUTE Pin Voltage vs MUTE ATT Ratio
(V+=3.3V , MICAMP GAIN=40dB, Rf=300kΩ, Ri=3kΩ, A-weighted)
10
10
0
0
-40℃
25℃
-30
85℃
-40
-50
-60
-30
85℃
-40
-50
-60
-70
-70
-80
-80
-90
-90
-100
-100
0
0.5
1
25℃
-20
MUTE ATT Ratio [dB]
-20
MUTE ATT Ratio [dB]
-40℃
-10
-10
1.5
2
0
2.5
0.5
1
MUTE Pin Voltage vs MUTE ATT Ratio
(V+=3.3V , MICAMP GAIN=0dB, Rf=3kΩ, Ri=3kΩ, A-weighted)
2.5
10
-40℃
0
-40℃
0
25℃
85℃
-20
-30
-20
-30
-40
-40
-50
-50
-60
25℃
85℃
-10
MUTE ATT Ratio [dB]
-10
MUTE ATT Ratio [dB]
2
MUTE Pin Voltage vs MUTE ATT Ratio
(V+=4.0V , MICAMP GAIN=0dB, Rf=3kΩ, Ri=3kΩ, A-weighted)
10
-60
0
0.5
1
1.5
2
2.5
0
0.5
1
MUT PIN Voltage [V]
1.5
2
2.5
MUT PIN Voltage [V]
MICAMP Gain vs Frequency
(V+=3.3V , RL=5.1kΩ, Cin=1µF, Rin=3kΩ)
MICAMP Gain vs Frequency
(V+=4.0V , RL=5.1kΩ, Cin=1µF, Rin=3kΩ)
50
50
Gv=40dB, Rf=300kΩ, Vin=1mV
Gv=40dB, Rf=300kΩ, Vin=1mV
40
40
-40℃
25℃
85℃
-40℃
25℃
85℃
30
Gain [dB]
30
Gain [dB]
1.5
MUT PIN Voltage [V]
MUT PIN Voltage [V]
20
10
20
10
Gv=0dB, Rf=3kΩ, Vin=100mV
Gv=0dB, Rf=3kΩ, Vin=100mV
0
0
-40℃
25℃
85℃
-10
-40℃
25℃
85℃
-10
10
100
1000
Frequency [Hz]
10000
100000
10
100
1000
10000
100000
Frequency [Hz]
–9–
NJW1124
! TYPICAL CHARACTERISTICS
Receive AMP. Gain vs Frequency
(V+=4.0V , RL=5.1kΩ, Cin=1µF, Rin=3kΩ
Receive AMP Gain vs Frequency
(V+=3.3V , RL=5.1kΩ, Cin=1µF, Rin=3kΩ)
50
50
Gv=40dB, Rf=300kΩ,Vin=1mV
40
30
30
Gain [dB]
Gain [dB]
Gv=40dB, Rf=300kΩ, Vin=1mV
40
20
20
10
10
Gv=0dB, Rf=3kΩ, Vin=100mV
0
Gv=0dB, Rf=3kΩ, Vin=100mV
0
-10
-10
10
100
1000
10000
10
100000
100
30
100000
30
28
28
Gv=26dB, Vin=50mV
Gv=26dB, Vin=50mV
26
24
24
22
22
Gain [dB]
26
20
20
18
18
16
16
14
14
12
12
10
10
10
100
1000
10000
10
100000
100
1000
10000
100000
Frequency [Hz]
Frequency [Hz]
Receive AMP THD+N vs Input Voltage
(V+=4.0V, RL=5.1kΩ , Gain=40dB , Rf=300kΩ , Ri=3kΩ , BW:400Hz-30kHz)
Receive AMP THD+N vs Input Voltage
(V+=3.3V, RL=5.1kΩ , Gain=40dB , Rf=300kΩ , Ri=3kΩ , BW:400Hz-30kHz)
10
THD+N [%]
10
THD+N [%]
10000
LINE AMP Gain vs Frequency
(V+=4.0V , RL=1.2kΩ, Cin=1µF, Rf=51kΩ, Rin=5.1kΩ, Cf=47pF)
LINEAMP Gain vs Frequency
(V+=3.3V , RL=1.2kΩ, Cin=1µF, Rf=51kΩ, Rin=5.1kΩ, Cf=47pF)
Gain [dB]
1000
Frequency [Hz]
Frequency [Hz]
1
1
85℃
85℃
25℃
25℃
-40℃
-40℃
0.1
0.0001
0.001
0.01
Input Voltage [Vrms]
– 10 –
0.1
0.1
0.0001
0.001
0.01
Input Voltage [Vrms]
0.1
NJW1124
! TYPICAL CHARACTERISTICS
Receive AMP THD+N vs Input Voltage
(V+=4.0V, RL=5.1kΩ , Gain=0dB , Rf=3kΩ, Ri=3kΩ, BW:400Hz-30kHz)
Receive AMP THD+N vs Input Voltage
(V+=3.3V, RL=5.1kΩ , Gain=0dB , Rf=3kΩ , Ri=3kΩ , BW:400Hz-30kHz)
10
10
1
THD+N [%]
THD+N [%]
1
0.1
-40℃
0.1
85℃
0.01
25℃
85℃
-40℃
0.01
0.01
25℃
0.1
1
0.001
0.01
10
0.1
Mic AMP THD+N vs Input Voltage
(V+=3.3V,MUT=0.3V, RL=5.1kΩ , Gain=40dB , Rf=300kΩ, Ri=3kΩ, BW:400Hz-30kHz)
10
85℃
(MUT=0.3V)
THD+N [%]
THD+N [%]
10
Mic AMP THD+N vs Input Voltage
(V+=4.0V,MUT=0.3V, RL=5.1kΩ , Gain=40dB , Rf=300kΩ, Ri=3kΩ, BW:400Hz-30kHz)
10
1
1
Input Voltage [Vrms]
Input Voltage [Vrms]
1
85℃
(MUT=0.3V)
85℃
(MUT=0V)
85℃
(MUT=0V)
25℃
25℃
-40℃
0.1
0.0001
0.001
-40℃
0.01
0.1
0.0001
0.1
0.001
Input Voltage [Vrms]
0.01
0.1
Input Voltage [Vrms]
Mic AMP THD+N vs Input Voltage
(V+=3.3V,MUT=0.3V, RL=5.1kΩ , Gain=40dB , Rf=300kΩ, Ri=3kΩ, BW:400Hz-30kHz)
Mic AMP THD+N vs Input Voltage
(V+=4.0V,MUT=0.3V, RL=5.1kΩ , Gain=40dB , Rf=300kΩ, Ri=3kΩ, BW:400Hz-30kHz)
10
10
1
THD+N [%]
THD+N [%]
1
0.1
85℃
(MUT=0.3V)
85℃
(MUT=0V)
-40℃
0.1
25℃
85℃
(MUT=0V)
0.01
85℃
(MUT=0.3V)
25℃
0.01
0.01
-40℃
0.1
1
Input Voltage [Vrms]
10
0.001
0.01
0.1
1
10
Input Voltage [Vrms]
– 11 –
NJW1124
! TYPICAL CHARACTERISTICS
LINE AMP THD+N vs Input Voltage
(V+=3.3V, RL=1.2kΩ , Gain=26dB , Rf=51kΩ, Ri=5.1kΩ, BW:400Hz-30kHz)
LINE AMP THD+N vs Input Voltage
(V+=4.0V, RL=1.2kΩ , Gain=26dB , Rf=51kΩ, Ri=5.1kΩ, BW:400Hz-30kHz)
10
THD+N [%]
THD+N [%]
10
1
1
85℃
85℃
25℃
-40℃
-40℃
25℃
0.1
0.001
0.01
0.1
0.1
0.001
1
0.01
0.1
Input Voltage [Vrms]
RTSW PIN Voltage vs Rx&Tx ATT. Gain
(V+=3.3V)
RTSW PIN Voltage vs Rx&Tx ATT. Gain
(V+=4.0V)
10
10
0
0
Tx 25℃
-10
Tx -40℃
-10
Rx -40℃
Tx 85℃
Rx 85℃
Rx 25℃
Rx -40℃
Rx 25℃
Tx 25℃
Rx 25℃
-20
-30
Rx 85℃
Tx 85℃
Rx 85℃
Rx & Tx ATT. Gain
Tx 85℃
Rx & Tx ATT. Gain
1
Input Voltage [Vrms]
-20
Tx 85℃
Rx 85℃
-30
Tx 25℃
Rx -40℃
Tx -40℃
Tx 25℃
Rx 25℃
Tx -40℃
Tx -40℃
Rx -40℃
-40
-40
-50
-50
0
0.5
1
1.5
2
RTSW PIN Voltage [V]
– 12 –
2.5
3
3.5
0
0.5
1
1.5
2
2.5
RTSW PIN Voltage [V]
3
3.5
4
NJW1124
■APPLICATION NOTES
■GENERAL DESCRIPTION
The NJW1124 is a Voice Switched Speakerphone Circuit. The NJW1124 includes all of functions
processing a high quality hands–free speakerphone system, such as the necessary amplifiers
( Microphone amplifier , Receive amplifier, Line amplifier), attenuators, level detectors .
All external capacitors are sufficient small so that ceramic capacitors are applied.
The NJW1124 detects a signal to judges which path is talking. After that, the one side path is
active, another path is attenuated. This is half-duplex system. Appropriate operating keeps closed loop
gain less than 0dB, and that prevents acoustic coupling.
The resister and capacitor values in Fig.1 below are references. For correct operating, check in
actual condition as possible as you can. And adjust the levels input each detectors.
On this application notes, Base unit is defined as the unit included the NJW1124.
C6 R2
100n 5.1k
R3
51k
C8
100n
C7
100n
C9
R6
100n 5.1k
R7
51k
Microphone
MCI
MUT
V+
GND
R4
51k
MCO
R5
10k
TLI2
TLI1
Line Out
C10
TXO
LII
LiO-
LiO+
V+
:MUTE
:ACTIVE
V+
R1
300k
C1
1µ
µ
C3
470n
C4
470n
C2
1u
-1
Tx Attenuator
Mic
Amplifier
VREF
Line Amplifier
Monitor
MUT
+
V
RLO2
CPT
Attenuator
Control
VREF
BIAS
Background
NoiseMonitor
CPR
TLO1
Rx Attenuator
RXO RLI2
R10
15k
5.0V
+
C16
10µ
µ
C15
1µ
µ
C20
470n
C21
470n
GND
VREF
1.2µ
µA
V+
C22
1µ
µ
Receive
Amplifier
IC1
NJW1124
VREF2
: Active
: Disable
V+
:Recive
GND :Trensmit
Open :idle
RTSW
Background
NoiseMonitor
RLO1
MUT
V+
GND
C5
1µ
µ
CT
Level
Detector
TLO2
Level
Detector
C23
1µ
µ
C11
1µ
µ
V+
VREF
C17
100n
C13
R11
10k
VLC
R12
51k
RVLC
RLI1 FO
C18
100n
R13
5.1k
FI
R14
5.1k
C19
100n
Recive In
1µ
Speaker
IC2
NJU7084
Power Amplifier
C14 1 µ
R9
22k
R8
11k
C12
100n
Fig.1 NJW1124 Block Diagram
The resistance and capacitor value above is just one example.
Certain Half-duplex operation are not guaranteed.
Best value depends on your microphone, speaker, and chassis.
Especially, select capacitor value connected to V+(17pin) to be power
supply ripple enough small (less than 5mVp-p).
when 1µF is not enough, select larger value capacitor.
– 13 –
NJW1124
1.Receive Attenuator
Receive Attenuator has 3 modes depending on base and satellite unit condition.
PARAMETER
SYMBOL
TEST CONDITION
MIN.
TYP.
MAX.
UNIT
Receive Attenuator Gain 1
GR1
RX-mode (Receive)
3.0
6.0
9.0
dB
Receive Attenuator Gain 2
GR2
-43
-46
-50
dB
Receive Attenuator Gain 3
GR3
TX-mode (Transmit)
Idle-mode
(Standby),CPT=CPR=V+
-17
-20
-23
dB
1.Receive Attenuator Gain 1 , (Receive mode :Gain=+6dB)
Condition: Receive signal from satellite unit, and no transmit signal to base unit.
2. Receive Attenuator Gain 2 , (Transmit mode :Gain=-46dB)
Condition: Transmit signal to base unit, and no receive signal from satellite unit.
3. Receive Attenuator Gain 3 , (Idle mode :Gain=-20dB)
Condition: Transmit signal to base unit, and no receive signal from satellite unit.
0
Volume Control
-10
Volume [dB]
Receive Attenuator includes Volume Control.
Volume is controlled by resister value connected
to VCL pin.
Fig.2 shows Volume attenuate vs. Resister value.
Volume max.(0dB) : 0Ω,
Volume min. (-40dB): 100kΩ .
-20
-30
Transmit Attenuator doesn’t equip Volume Control.
-40
0
20
40
60
VLC Resistor [kΩ]
80
Fig.2 Volume vs. VCR Resister
– 14 –
100
NJW1124
2.Transmit Attenuator
Transmit Attenuator has 3 modes depending on base and satellite unit condition.
PARAMETER
SYMBOL
TEST CONDITION
MIN.
TYP.
MAX.
UNIT
Transmit Attenuator Gain 1
GT1
RX-mode (Receive)
3.0
6.0
9.0
dB
Transmit Attenuator Gain 2
GT2
-43
-46
-50
dB
Transmit Attenuator Gain 3
GT3
TX-mode (Transmit)
Idle-mode
(Standby),CPT=CPR=V+
-17
-20
-23
dB
1.Transmit Attenuator Gain 1 , (Transmit mode :Gain=+6dB)
Condition: Receive signal from satellite unit, and no transmit signal to base unit.
2. Transmit Attenuator Gain 2 , (Transmit mode :Gain=-46dB)
Condition: Transmit signal to base unit, and no receive signal from satellite unit.
3. Transmit Attenuator Gain 3 , (Idle mode :Gain=-20dB)
Condition: Transmit signal to base unit, and no receive signal from satellite unit.
3.Microphone Amplifier
Microphone Amplifier is an operational Amplifier amplifying the signal from microphone to line level.
Fig.3 shows Block Diagram of Mic.Amp..
Non-inverting input keeps reference voltage inside. Mic.Amp is used as inverting amplifier. The Gain should be
40dB or less.
Mic.amp equips Mute function.
C6 R2
100n 5.1k
R3
51k
Microphone
MCI
MUT
V+
GND
:MUTE
:ACTIVE
V+
MCO
R1
300k
Tx Attenuator
VREF
C1
1µ
µ
Mic
Amplifier
Fig.3 Mic.Amp Block.(20dB Application)
Outside parts
C6
R2
R3
R1
C1
Function
DC decoupling
recommend value
100nF～10µF
Gain Setting
3kΩ～300kΩ
Pop noise
reduction
100Ω～300kΩ
100n～10µF
MUT(2pin) Input Voltage
VIH
>1.5V
VIL
<0.3V
Detail
Gv=R3/R2
Input impedance＝R2
The control voltage is made
gradual with RC filter.
Memo
Shape HPF : fc=1/(2π×C6×R2)
Recommend gain less than :40dB
Large resistance value may cause oscillating.
-
Operation
MICAMP MUTE
MICAMP ACTIVE
– 15 –
NJW1124
4.Receive Amplifier
Receive Amplifier is an operational Amplifier receiving the signal from satellite unit.
Fig.4 shows Block Diagram of Mic.Amp Block Non-inverting input keeps reference voltage inside.
Receive Amp is used as inverting amplifier. The Gain should be 40dB or less.
Receive Amplifier doesn’t equip Mute function.
Receive
Amplifier
Rx Attenuator
VREF
FO
R13
5.1k
FI
R14
5.1k
C19
100n
Recive In
Fig.4 Receive.Amp Block.(0dB Application)
Outside parts
C19
R１4
R１3
– 16 –
Function
DC decoupling
recommend value
100nF～10µF
Gain Setting
3kΩ～300kΩ
Detail
Gv=R13/R14
Input impedance＝R14
Memo
Shape HPF : fc=1/(2π×C19×R14)
Recommend gain less than :40dB
Large resistance value may cause oscillating.
NJW1124
5.Line Amplifier
Line Amplifier transmits the signal from Tx attenuator to satellite unit. Line Amplifier consists of two operational
Amplifiers.
First Amplifier non-inverting input keeps reference voltage inside. First Amplifier is used as inverting amplifier.
Second Amplifier includes –1 fixed Gain.
These two amplifiers enable to differential output from single-ended signal.
C9
R6
100n 5.1k
R7
51k
Line Out
C10
TXO
LII
LiO-
LiO+
-1
VREF
Line Amplifier
Fig.5 Line Amplifier Block(26dB Application)
Outside parts
Function
DC decoupling
C9
R6
Gain Setting
R7
C10
oscillation prevention
recommend value
100nF～10µF
Detail
Gv=R7/R6
Input impedance＝R6
3kΩ～300kΩ
10p～100pF
Memo
Shape HPF : fc=1/(2π×C9×R6)
Recommend gain less than :26dB
Large resistance value may cause oscillating.
Shape LPF : fc=1/(2π×C10×R7)
Line Amplifier may oscillates, long transmission path becoming large capacitive load. In this case, add ceramic
capacitor (47p to 100p) between LII and LIO-.
Add it as close as possible to the terminal. The frequency should be cut more than you need.
LIO+,LIO- should not be short to GND. LIO+,LIO- terminal are biased to V+/2).
C11 R8
100n 5.1k
R9
51k
LINE Cable
CfL
TXO
LII
LiO-
LiO+
-1
VREF
Line Amplifier
Fig.6 Forbidden Circuit.
– 17 –
NJW1124
6.Monitor Terminal
Monitor Terminal switches Voltage mode depending NJW1124 condition.
NJW1124 condition : Monitor Terminal Voltage
Receive mode
V+
Transmit mode
GND
Idle mode
Hi-Z or (V+/2)
7.Level Detector Block
The NJW1124 includes Level Detector Block and Background Noise Monitor on transmit block and receive block.
Level Detector Block consists of two same detectors.
Fig.7 shows Level Detector block.
The signal(S1 to S4) output each detector transmits to attenuator controller to change the mode.
Next 7.1 and 7.2 explain about each detector and Background Noise Monitor operation details.
About S1 to S4 signals, refer to 8 part.,
Tx : TLO2
Rx : RLO1
Tx : TLI2
Rx : RLI1
Level
Detector
Circuit
Tx : RLI2
Rx : TLI1
Level
Detector
Circuit
Background
Noise
Monitor
Tx : S1
Rx : S2
Tx:RLO2
Rx:TLO1
Fig.7 Level Detector Block
– 18 –
Tx : S3
Rx : S4
NJW1124
7.1 Level Detector Circuit
Fig.8 shows level detector circuit.
Level detector circuit includes logarithmic amplifier using diodes (D1,D2) to keep dynamic range.
The signals input to each level detector through external coupling capacitor Ci , are converted to current by input
resistance Rin and input logarithmic amplifier through TLI2,1 and RLI1,2.
The current input changes diode(D1) current .
When the current more than 0.54µA(Current Source circuit ) inputs ,diode D1 is off, and A point voltage drops.
In case of sinking current, the current increase D1 current, that increase A point voltage rises.
The point voltage is defined as follows.
.
-6
-6
∆VA=0.026 x Ln [ { Iin + (0.54x10 ) } / (0.54x10 ) ]
Iin=Vin/Rin.( Actually, Ci effects)
The voltage A point goes through buffer Amplifier AMP2, charge the capacitor connected to TLO1.2,RLO1.2.
The charging completes immediately.
Response Example1 shows TLO2(Co=C5=0.1µF) signal waveform outputting 200mVrms/1kHz from
MICOUT(MCO pin).
without input signal from TL1,TL2,RL1,and RL2,Co releases current.
The Voltage Gradient is defined as follows:
δVc=-0.3µA/Co
Response Example 2 shows the signal response finishing input the signal.
Actual application being influenced on leak current and equivalent resistance in series,
δVc does not accords with the formula completely. Check on the operation using actual capacitor
(Use high input impedance probe like FET Measuring instrument)
Small capacitor shortens the time to detect, and deteriorate the low frequency rectification characteristics.
That influences on Noise Detector on next page.
Large capacitor improves rectification characteristics, and noise detector function.
However, extends the time to detect, it may judges the signal on noise.
Appropriate capacitor value depends on a application.
The input current TLI1,TLI2,RLI1,and RLI2 should be less than 100µΑ
µΑ for normal operating .
Especially, gain mode has 9dB gain max, care of excessive input.
Voice switch circuit may malfunctions with Excessive input current
Fig.9 shows Rin(input impedance) vs. minimum input sensitivity of noise detector and maximum permissible
voltage.
Ci
(C7,C8
C18,C17)
Rin
(R4,R5
TLI2,1
R12,R11)
RLI1,2
D1
Vin
D2
Iin
TLO2,1
RLO1,2
AMP2
AMP1
A
IO
Ref
I2
0.54uA
I1
0.54uA
I3
0.3uA
Co
(C3,C20
C21,C4)
Fig.8 Level Detector Circuit Diagram
Outside parts
Cin
Rin
Function
DC decoupling
V/I Convert
recommend value
100nF～1µF
5kΩ～100kΩ
Detail
Iin＝Vin/Rin
Co
Detection level keeping
0.05µF～1.0mF
δVC ＝ -0.3uA / CO
Memo
Shape HPF : fc=1/(2π×Cin×Rin)
Use " Iin " by 100mA or less.
Use the capacitor leaking a little. Small capacitor
deteriorate the low frequency rectification
characteristics .
– 19 –
NJW1124
1040
400
1040
MCO
TLO2
MCO
TLO2
200
1000
200
1000
100
980
100
980
0
960
-100
-200
MCO [mV]
300
TLO2 [mV]
1020
MCO [mV]
300
1020
0
960
δVc
940
-100
940
920
-200
920
900
-300
900
880
-400
TLO2 [mV]
400
⊿VA
-300
-400
0
1
2
3
4
5
880
0
6
5
10
15
20
25
30
35
40
time [m sec]
time [m sec]
Response example.2
MCO vs. TLO2signal (finishing input)
MCO = 200mVrms/1kHz C5 = 0.1µF
Response example.1
MCO vs. TLO2signal (starting input)
MCO = 200mVrms/1kHz C5 = 0.1µF
10000
Minumum Sensitivity Voltage
Maximum Input Voltage(Vin(Fig.8)),which equal
to MCO or FO Maximum Output Voltage
MCO or FO Pin AC Voltage[mVrms]
Maximum Input Voltage
1000
Minimum Input Voltage(sensitivity),which is the Voltage
shifting mode(idle to receive, idle to transmit).
100
Note: Maximum Voltage is defined by the smaller resister,
35% value of R5, R11 or R4, R11 value.
10
1
10
Input Resistance[kΩ]
100
Fig.9 Minimum Input Voltage vs. Input Resistance
(R4 or R12 Theoretical Value resistance
R4=R5,R12=R11 condition)
– 20 –
NJW1124
7.2 Background Noise Monitor
Background Noise Monitor judges whether the input signal is noise or sound or voice by TLO2 and RLO2 voltage,
and change the mode.
The NJW1124 includes the Background noise monitor on transmit side and receive side.
Fig.10 shows Block diagram of Background noise monitor.
The voltage difference between TLO2 or RLO1 and Ref is amplified 8.6dB on AMP1.
nd
The signal from AMP1 inputs 2 stage AMP2 and comparator (COMP).
The COMP non-inverting input voltage becoming 36mV higher than inverting, COMP output 1,which shows the
NJW1124 is transmit or receive mode.
At the same time, external capacitor charged from 0.8µA internal current source, until the CCP voltage becomes
46mV higher than AMP2 input voltage.
The equivalent below shows CCP voltage charging.
∆VCCP= 0.8µA/CCP
For example, CCP=1µF, δVCP=0.8V/sec.
Without the input signal, C CP discharged and finally reset the Background noise monitor.
Response example is ex.3.
The signal like continued sign wave inputting, COMP output ‘0’ which is noise-monitoring mode (idle-mode).
The signal like conversation sound inputting, CCP continues to charge and discharge. COMP output continued
to ‘1’, which is transmit or receive mode.
Small Ccp shortens the time shifting to ‘0’ condition. Too small CCP attenuates even the conversation signal.
Large CCP keeps ‘1’ condition long, which lengthen attenuating time.
Capacitor should be adjusted appropriately on actual application.
(Use high input impedance like FET probe measuring voltage of CPT, CPR pin.)
CCP
(C2,C22)
Tx : TLO2
Rx : RLO1
Tx : CPT
Rx : CPR
19kΩ
32kΩ
AMP2
AMP1
Level
Detector
0.8µ
µA
46mV
COMP
Ref
Tx : S3
Rx : S4
36mV
Fig.8 Background Noise Monitor Block Diagram
Function
Noise Detection
recommendation value
100nF～1µF
Detail
-
1300
1300
TLO2
CPT
1250
TLO2
CPT
1250
1200
1200
1150
1150
TLO2 , CPT [mV]
TLO2 , CPT [mV]
Memo
The time for noise detection depends on this.
1100
1050
1000
1100
1050
1000
950
950
900
900
850
850
800
800
0
100
200
300
400
time [m sec]
Response example.3
TLO2 vs. CPT signal (input start)
MCO = 200mVrms/1kHz
C5 = 0.1µF, C4=1µF
500
0
10
20
30
40
50
time [m sec]
Response example.4
TLO2 vs. CPT signal (input finish)
MCO = 200mVrms/1kHz
C5 = 0.1µF, C4=1µF
– 21 –
NJW1124
8.Attenuator Controller
Attenuator Controller controls each mode(Transmit or Receive or idle) by the signal(S1 to S4) from level detector
according as table.1 below
Table.1 shows truth table (On RTSW=Open).
Internal 12µA current source circuit charges and discharges C7, connected with CT pin
On the mode changing condition, δVC5 shows voltage change according as the formula below. .
δVC7 = ±12uA/C5 (11.1)
(C7 is C5 capacitance connected to CT pin.)
on initial state, CT pin voltage equals to Vref voltage. Shifting to transmit mode, C7 discharges and become lower
voltage than Vref voltage. Example 5 and 6 shows behaviors. VCT voltage is CT voltage minus Vref voltage.
On receive mode, internal current source charging C5 raises CT voltage.
CT pin voltage shows operating condition(Transmit or Receive or idle).
( more than 100MΩ impedance probe should be monitoring the voltage.
‘FAST idle mode’ enables to shift promptly charging C7 rapidly.
On ‘SLOW idle mode’, mode shifts gently.
Both time constants τ are below:
τ=RAXC5
(RAX is RA1 RA2 resistance. After τ sec, The voltage is attenuated to 1/e default value)
For example, C7=1µF, τ =600m sec.
attenuator gain GAT estimate as below:
GAT(TX) = 0.1 x exp { -VCT / 0.026 } on transmit mode
GAT(RX) =0.1 x exp { VCT / 0.026 }
on receive mode
(11.3)
(11.4)
C5 = 1µF, attenuator time constant on SLOW idle mode is about 225m sec.
Table.6 as below shows response of transmit signal wave:
Fig.11 shows VCT vs. GAT.
Adjust this order for appropriate operating:
1.Resistance connecting to TLI1.2 and RLI1.2
2.Capacitor connecting to TLO1.2 and RLO1.2
3.Capacitor connecting CPT, CPR.
When adjusting above doesn’t enable to appropriate operating(attenuating too fast or shifting too slow etc.),
adjust C5 value connecting to CT pin . Typical value is 1µF.
Table.1 Truth Table
S1
Tx
Tx
Rx
Rx
Tx
Tx
Rx
RX
– 22 –
S2
Tx
Rx
Tx
Rx
Tx
Rx
Tx
Rx
S3
1
y
y
X
0
0
0
X
S4
X
y
y
1
X
0
0
0
Mode
Tx Mode
FAST Idle Mode
FAST Idle Mode
Rx Mode
SLOW Idle Mode
SLOW Idle Mode
SLOW Idle Mode
SLOW Idle Mode
S1 ：Result comparing RLO2 and TLO2
(RLI2 and TLI2 •••Detecting Base Unit side)
RLO2>TLO2 [Rx]
TLO2>RLO2 [Tx]
S2 ：Result comparing RLO1and TLO1
(RLI1 and TLI1•••Detecting Satellite Unit side)
RLO1>TLO1 [Rx]
TLO1>RLO1 [Tx]
S3＆S4 ：Output Background Noise Monitor
[1]:Detecting signal
[0]:Judging noise
[x]：Don’t Care
[y]：Both C3 and C4 is not 0.
NJW1124
10
VCT
MCO
0
400
800
300
600
200
400
100
200
TXO
MCO
-10
-50
-100
MCO , TCO [mV]
0
-40
0
-200
-60
-200
-400
-300
-600
-400
-800
-70
-80
-90
0
2
4
6
8
10
12
14
0
2
4
6
time [m sec]
10
8
10
12
14
time [m sec]
Response example.5
MCO vs. CT-VREF signal (input start)
MCO = 200mVrms/1kHz
C7=1µF
Response example.6
MCO vs. TXO(AC) signal (input start)
MCO = 200mVrms/1kHz C7=1µF
2.5
800
0
TXO
GATTx
600
2.0
1.5
-10
400
1.0
-20
200
-40
-50
0.5
0.0
0
-0.5
-200
-60
GAT(Tx)
TXO [mV]
VCT [mV]
-30
-1.0
360m sec
-400
-70
-1.5
-600
-80
-2.0
-800
-90
0
250
500
750
1000
1250
1500
1750
2000
0
250
500
750
1000
1250
1500
1750
-2.5
2000
time [m sec]
time [m sec]
Response example.7
CT-VREF signal (input continue)
MCO = 200mVrms/1kHz C7=1µF
SLOW idle mode
Response example.8
GAT vs. TCO signal (input start)
MCO = 200mVrms/1kHz C7=1µF
SLOW idle mode
10
GAT(TX)
GAT(RX)
0
-10
GAT [dB]
VCT [mV]
-30
MCO[mV]
-20
-20
-30
-40
-50
-100
-75
-50
-25
0
25
50
75
100
VCT [mV]
Fig.11 GAT vs. VCT Calculated Spectrum
– 23 –
NJW1124
RTSW shifts the mode forcibly. RTSW changes the CTpin voltage forcibly to shift the mode.
Ex.9 shows the response to RTSW.
100
80
Rx Mode Level
60
40
VCT [mV]
20
0
RTSW State :
Rx -> Tx
-20
-40
-60
-80
Tx Mode Level
-100
0
2
4
6
8
10
12
14
16
18
20
time [m sec]
Response example.9
RTSW shifting (Receive mode to Transmit mode)
C7=1µF
– 24 –
NJW1124
10.Acoustic Coupling Reduction
To reduce Acoustic Coupling, isolating speaker and microphone is effective.
Adjusting resistance value connected to TLI1, TLI2, (R4, R5, R11) and RLI1 is also effective,
For example, configure R12,R4 value is 2 to 6 times than R5,R11.
Reducing sensitivity to echo enables to operate normally.
C6 R2
100n 5.1k
R3
51k
C9
R6
100n 5.1k
C8
100n
C7
100n
R7
51k
Microphone
R4
51k
MCO
MCI
TLI1
Line Out
C10
R5
10k
TLI2
TXO
LII
LiO-
LiO+
V+
V
+
R1
300k
Sensitivity:Low
VREF
C1
1µ
µ
Receive Voice
Acoustic coupling
C3
470n
C4
470n
C2
1u
-1
Tx Attenuator
Mic
Amplifier
C11
1µ
µ
V+
VREF
Line Amplifier
Monitor
MUT
Level
Detector
TLO2
V
Setting TLI2 resistance (R4) twice to
RTSW
6times than RLI2
resistance
(R11),
Background
C22
NoiseMonitor
reduces the level
detector sensitivity
1µ
µ
CPR
to reduce acoustic coupling.
C20
+
RLO2
Background
NoiseMonitor
CPT
C5
1µ
µ
CT
Attenuator
Control
Sensitivity:High
Level
Detector
TLO1
RLO1
C23
1µ
µ
VREF
BIAS
C21
470n
Receive
Amplifier
IC1
NJW1124
VREF2
470n
Rx Attenuator
GND
VREF
1.2µ
µA
RXO RLI2
V+
R10
15k
+
C16
10µ
µ
C15
1µ
µ
VLC
C17
100n
C13
R11
10k
RLI1 FO
R12
51k
5.0V
RVLC
C18
R13
FI
R14
100n
5.1k
Receive
Sound5.1k
C19
100n
Recive In
1µ
Speaker
IC2
NJU7084
Power Amplifier
C14 1 µ
R9
22k
R8
11k
C12
100n
Fig.12 Acoustic Coupling Reduction
Reducing the sensitivity of R4,R12 reduces the time shifting to noise mode.
In case of too fast shifting, enlarge capacitor connected to CPT,CPR.
– 25 –
NJW1124
Notes:1
To reduce Pop-Noise of power-on and off.
Appropriate power supply sequence reduces pop-noise.
Initial condition: No power supply.
CD switch of Speaker Amplifier should be standby condition.
The circuit connected to Line out and Receive In is off.
Power-on sequence
1.Power-on NJW1124. Concurrently The circuit connected to Receive In power on.
2.After 1 sec later, the circuit connected to Line OUT and Speaker Amplifier IC power on.
3.After 1 sec later, Speaker Amplifier IC shifts active mode.
Power-off sequence
1.Speaker Amplifier shift standby mode.
2.After 1 sec later, the circuit connected to Line OUT and Speaker Amplifier power off.
3.After 1 sec later, NJW1124 power off. Concurrently, the circuit connected to Receive In power off.
– 26 –
NJW1124
Notes:2:
Filter circuit using Receive amplifier, Mic. Amplifier, Line amplifier.
st
Receive amplifier, Mic. Amplifier, Line amplifier enable to form active filter circuit which is 1 order or 2
HPF or LPF or BPF.
nd
order,
st
1.1 order HPF,LPF circuit example
st
Fig.13 shows 1 order (-6dB/oct) HPF, LPF circuit.
Combining HPF formed by Co and R1, and LPF formed by C1 and R2, forms BPF.
(Co should be also used typical application as DC decoupling.)
R2
C0
f C ( LPF )
R1
FI
Receive In
1
2πC0 R1
1
=
2πC1 R2
f C ( HPF ) =
C1
Response
FO
+6dB/oc
-6dB/oct
Ref
st
Fig.13 1 order HPF,LPF circuit example
Frequency
fc(HPF)
fc(LPF)
nd
2.2 order LPF circuit example
st
Fig.14 shows 1 order (-12dB/oct) LPF circuit.
Same as 1st order filter, Co should be used as DC decoupling. C2 selecting arbitrarily, Butterworth filter forming
coefficient is as below.
R2
C0
FI
Receive In
FO
C1
Ref
Fig.14 2
nd
1
2 2Gπf C ( LPF )C2
R2 =
1
C2
R3
R1
R1 =
order LPF circuit example
Response
R3 =
2 2πf C ( LPF )C2
1
2 2 (G + 1)πfC ( LPF )C2
C3 = 2(G + 1)C2
G = Gain
+6dB/oc
-12dB/oct
Frequency
fc(HPF)
fc(LPF)
st
fC(HPF) is same as 1 order type above.
– 27 –
NJW1124
Fig.15 shows 2
nd
order LPF(Gain=20dB, fc(LPF) = 4kHz) circuit example.
C0
nd
510p
FI
Receive In
Fig.15 2
5.6k
56k
5.1k
FO
12n
Ref
order LPF(Gain=20dB, fc(LPF) = 4kHz, Butterworth filter)
circuit example.
nd
3.2 order HPF circuit example
st
Fig.16 shows 2 order (-12dB/oct) HPF circuit.
Co=C2, Butterworth filter forming coefficient is as below.
C1
C0
R2
R1 =
C2
FI
Receive In
R2 =
FO
R1
nd
2G + 1
2πf C ( HPF )C0
C0
G
* C0 = C 2
C1 =
Ref
Fig.16 2
2
2πf C ( HPF )C0 (2 + 1 / G )
order HPF circuit example.
Fig.17 shows HPF(Gain=20dB,Fc(HPF)=200Hz) circuit example.
100n
10n
100n
160k
FI
Receive In
FO
5.6k
Ref
nd
Fig.17 2 order HPF circuit example.
Gain=20dB,Fc(HPF)=200Hz, Butterworth filter
– 28 –
NJW1124
Notes:3 list of Parts of Attenuator controller
Terminal
Cin
Parts
Recommend Value
C7,C8,C17,C1 100nF～1µF
Rin
R4,R5,R11,R125.1k～51kΩ
Co
C4,C5,C20,C2 0.05µF～1µF
Ccp
C2,C22
100nF～1µF
Cct
C5
1µF
Notes
The input capacitor forms HPF with Rin.
V-I converter,which depends on sensitivity of each level detectors and noise
detector. Smaller value lower detection level. Larger value raise detection level.
Input voltage should be less than 100mA(200µΑ @25oC).
The capacitor keeps voltage level.Larger value extends swicthing time.Smaller
value shortens swicthing time, and deteriorate rectification property that adverse
affects back ground noise monitor on low frequency signal.
The capacitor judges whether the signal is noise.Larger value extends the judging
time.Smaller value shortens the judging time.
The capacitor generates the voltage controlling attenuater. Larger value extends
attenuating time on switching and idle mode.Smaller value shortens the
attenuating time.Please be careful of conduction caused by condensation due to
this terminal is high impedance.Attenuater gain may be fluctuant .
[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.
– 29 –