NJM2760
Band Pass Filter for Spectrum Analyzer Display
s
GENERAL DESCRIPTION
The
NJM2760
is a band pass filter for spectrum analyzer display.
It includes 4-band BPF amplifier, 4-band detector and recording
level indicator output.
It is suitable for mini-components, CD radio cassette and other
audio components.
s
PACKAGE OUTLINE
NJM2760V
s
FEATURES
q
Operating Voltage
+2.7V to +9V
q
4 Band Pass Filters & Detector
q
Recording Level Indicator Output
q
Low Offset Voltage
5mV typ.
q
Adjustable Input Sensitivity
q
Bipolar Technology
q
Package Outline
SSOP20
s
PIN CONFIGURATION
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
IN1
IN2
BUF1OUT
BPF2IN1
BPF2IN2
BPF3IN1
BPF3IN2
BPF4IN1
BPF4IN2
GND
20. BUF2OUT
19. BPF1IN2
18. BPF1IN1
17. RECOUT
16. BPF1OUT
15. BPF2OUT
14. BPF3OUT
13. BPF4OUT
12. N.C.
11. V+
s
BLOCK DIAGRAM
5.6kΩ
10kΩ
6.8kΩ
22nF
47nF
4.7nF
V+
1µF
BPF
DET
1µF
BPF4 out
BPF
200kΩ
DET
1µF
BPF3 out
L in
R in
200kΩ
BPF
1µF
DET
1µF
BPF2 out
BPF
200kΩ
200kΩ
1µF
DET
1µF
BPF1 out
DET
1µF
REC out
GND
470pF
–1–
NJM2760
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ABSOLUTE MAXIMUM RATING
(Ta=25°C)
PARAMETER
Supply Voltage
Power Dissipation
Operating Temperature Range
Storage Temperature Range
SYMBOL
V
+
RATINGS
14
300
-20 to +75
-40 to +125
UNIT
V
mW
°C
°C
P
D
Topr
Tstg
s
ELECTRICAL CHARACTERISTICS
(Ta=25°C, V+=3.3V, V
IN
=1V
PEAK
unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITION
MIN.
TYP.
MAX.
UNIT
x
Power Supply
Operating Voltage
Operating Current
V
+
-
No Signal
Vin=1V
peak
,
f=Center Frequency of BPF
Vin=3V
peak
,
f=Center Frequency of BPF
f=8kHz
f=1.2kHz
f=300Hz
f=80Hz
No Signal
2.7
-
3.3
1.4
9.0
3.0
V
mA
Icc
x
AC CHARACTERISTICS
Typical Output Voltage
Maximum Output Voltage
BPF1 Center Frequency Level
BPF2 Center Frequency Level
BPF3 Center Frequency Level
BPF4 Center Frequency Level
DC Offset Voltage
V
OT
V
OM
G
VBPF1
G
VBPF2
G
VBPF3
G
VBPF4
V
OS
0.7
2.1
-3
-3
-3
-3
-
1.0
3.0
0
0
0
0
5
1.42
-
+3
+3
+3
+3
30
V
V
dB
dB
dB
dB
mV
x
TEST CIRCUIT
R1 100kΩ
IN1
R2 100kΩ
IN2
C2 1
µ
F
2
3
C3 4.7nF
R3 6.8kΩ
C4 4.7nF
5
C5 22nF
R4 5.6kΩ
C6 22nF
7
C7 47nF
R5 10kΩ
C8 47nF
9
10
BPF4IN2
GND
8
BPF4IN1
BPF3IN2
6
BPF3IN1
BPF2IN2
4
BPF2IN1
IN2
BUF1OUT
C1 1
µ
F
1
IN1
BUF2OUT
20
C16 470pF
BPF1IN2
BPF1IN1
RECOUT
BPF1OUT
BPF2OUT
BPF3OUT
BPF4OUT
NC
V+
19
C15 470pF
18
17
16
15
14
13
12
11
RECOUT
BPF1OUT
BPF2OUT
BPF3OUT
BPF4OUT
NJM2760
C14 1
µ
F
C13 1
µ
F
C12 1
µ
F
C11 1
µ
F
C10 1
µ
F
+
C9
1
µ
F
V+
–2–
NJM2760
s
TERMINAL DESCRIPTION
No.
SYMBOL
FUNCTION
EQUIVALENT CIRCUIT
VOLTAGE
1
2
5
7
9
19
IN1
IN2
BPF2IN2
BPF3IN2
BPF4IN2
BPF1IN2
Input for BPF1-4
Input for recording level detector
Capacitor terminal for BPF2
Capacitor terminal for BPF3
Capacitor terminal for BPF4
Capacitor terminal for BPF1
680Ω
1.4V
3
20
BUF1OUT
BUF2OUT
Buffer output
Buffer output
FB
680Ω
1.4V
4
6
8
18
BPF2IN1
BPF3IN1
BPF4IN1
BPF1IN1
Capacitor terminal for BPF2
Capacitor terminal for BPF3
Capacitor terminal for BPF4
Capacitor terminal for BPF1
680Ω
1.4V
13
14
15
16
17
BPF4OUT
BPF3OUT
BPF2OUT
BPF1OUT
RECOUT
BPF4 output
BPF3 output
BPF2 output
BPF1 output
Recording level detector output
0V
90kΩ
FB
30kΩ
10
GND
Ground terminal
-
11
V+
Power supply terminal
-
–3–
NJM2760
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APPLICATION CIRCUIT
LIN
RIN
R11 200kΩ
R12 200kΩ
R21 200kΩ
R22 200kΩ
C1 1
µ
F
1
C2 1
µ
F
2
3
C3 4.7nF
IN2
BUF1OUT
BPF2IN1
BPF2IN2
BPF3IN1
BPF3IN2
BPF4IN1
BPF4IN2
GND
IN1
BUF2OUT
20
C16 470pF
BPF1IN2
BPF1IN1
RECOUT
BPF1OUT
BPF2OUT
BPF3OUT
BPF4OUT
NC
V+
19
C15 470pF
18
17
16
15
14
13
12
11
RECOUT
BPF1OUT
BPF2OUT
BPF3OUT
BPF4OUT
NJM2760
R3 6.8kΩ
C4 4.7nF
4
5
C5 22nF
C14 1
µ
F
C13 1
µ
F
C12 1
µ
F
C11 1
µ
F
C10 1
µ
F
R4 5.6kΩ
C6 22nF
6
7
C7 47nF
R5 10kΩ
C8 47nF
8
9
10
+
C9
1
µ
F
V+
–4–
NJM2760
s
APPLICATION NOTE
1. Center Frequency Setting for Band Pass Filters
Band pass filters equivalent circuits as follows.
External Circuit
Internal Circuit
External Circuit
Internal Circuit
C
Rb
C
to Detector
C
Rb
Ra
C
to Detector
Ra
from Input Buffer
from Input Buffer
Fig.1-a. BPF1's Equivalent Circuit
Fig.1-b. BPF2-4 's Equivalent Circuit
Center Frequency (fo) can be formulated as follows.
Table 1. Center frequency setting example
f
0
=
2Q
2
π
CR
b
[Hz],
Q=2
BPF1 (8kHz)
BPF2 (1.2kHz)
BPF3 (300Hz)
BPF4 (80Hz)
Ra
)
10 kΩ*
6.8 kΩ
5.6 kΩ
10 kΩ
Rb
)
169 kΩ*
)
113 kΩ*
)
96.5 kΩ*
)
169 kΩ*
C
470pF
4.7nF
22nF
47nF
*
) As regards the BPF1, the values of Ra and Rb are fixed. Also as regards the BPF2-4, the values of Rb is fixed.
2. Output Gain Setting for RECout.
Output Voltage of RECout is adjustable by external resistor: R2
Voltage Gain (Gv) is defined as follows.
R [k
Ω
]
Vout[ Vdc ]
=
G
v
=
2
100[k
Ω
]
Vin[ Vpeak ]
–5–
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