PASS FILTER. NJU7505A Datasheet

NJU7505A FILTER. Datasheet pdf. Equivalent

NJU7505A Datasheet
Recommendation NJU7505A Datasheet
Part NJU7505A
Description BAND PASS FILTER
Feature NJU7505A; NJU7505A BAND PASS FILTER FOR AUDIO SPECTRUM ANALYZER DISPLAY GENERAL DESCRIPTION The NJU7505A is .
Manufacture New Japan Radio
Datasheet
Download NJU7505A Datasheet




New Japan Radio NJU7505A
NJU7505A
BAND PASS FILTER
FOR AUDIO SPECTRUM ANALYZER DISPLAY
GENERAL DESCRIPTION
The NJU7505A is a band pass filter for audio spectrum
analyzer display.
It consists of high and low band pass filters, CR oscillation
circuit, control circuit and DC transfer circuit.
Each band pass filter using the switched capacitor filter
technology operates at the shared time by 5 bands which
filter constant is switched by the internal clock.
Therefore, the audio signal shared of 5 bands is output
from a serial output terminal.
The 10 bands version using the double by the cascade
connection is prepared.
PACKAGE OUTLINE
NJU7505AD NJU7505AM
FEATURES
BPF for the audio spectrum analyzer display of the 5 bands
10 bands extension is available by the cascade connection
BPF using the switched capacitor filter technology
CR oscillation circuit on chip
(External clock input is available)
Power-on initialization circuit on chip
(External reset input is available)
C-MOS Technology
Package Outline
DIP8, DMP8
PIN CONFIGURATION
OSC1 1
OSC2 2
RSTb/CLKO
RD
3
4
5
6
7
8
VDD
AIN
AOUT
VSS
BLOCK DIAGRAM
RSTb/CLKO
RD
Audio Signal
Control Signal
Clock Signal
OSC1
OSC2
OSC
Control Circuit
fOSC fOSC/16 fOSC/4 iH
iL RL
RH
ΦH ΦL
Power-on
Initialize
AIN
Input BUF
LPF
VDD
VSS
VDD
-
+
AGND
VSS
BPF
High Band
High Band
Peak Detector
BPF
Low Band
Low Band
Peak Detector
Level Shifter
&
Output BUF
AOUT
Ver.2008-07-30
-1-



New Japan Radio NJU7505A
NJU7505A
TERMINAL DESCRIPTION
NO. SYMBOL
1 OSC1
2 OSC2
3 RSTb/CLKO
4 RD
5 VSS
6 AOUT
7 AIN
8 VDD
FUNCTION
External Resistor connecting terminal.
External Resistor connecting terminal or External clock input terminal.
Both as Reset input terminal
and the clock of (2/3)*fOSC output terminal.
Trigger signal for reading-out the AOUT of each band output terminal.
GND
0V
Peak voltage of each band output terminal.
Audio signal input terminal.
Positive power supply +5.0 V
PEAK FREQUENCY
The peak frequency in each band of NJU7505A are a suitable band interval which is the 5 bands at using
the single and is the 10 bands at using the double by the cascade connection.
Band
f1a
f1b
f2a
f2b
f3a
f3b
f4a
f4b
f5a
f5b
Peak Frequency ( Hz )
Using the single
Using the double
12k 12k
- 8k
3.5k 3.5k
- 2.3k
1k 1k
- 670
250 250
- 165
63 63
- 42*
Note 1) It may not be output along the expectation at the peak frequency of * marking, since the sampling
time is not enough.
Note 2) The bands of f1a, f2a, ... f5a correspond to the master side and the bands of f1b, f2b, ... f5b
correspond to the slave side at the cascade connection of the double.
The example of using the single
OSC1
AOUT
f1a~f5a
NJU7505A
fOSC OSC2
VSS
fOSC
VSS
The example of using the double
OSC1
AOUT
NJU7505A
Master
OSC2
RSTb/
CLKO
f1a~f5a
2/3 x fOSC
OSC1
AOUT
NJU7505A
Slave
OSC2
f1b~f5b
-2-
Ver.2008-07-30



New Japan Radio NJU7505A
NJNUJ7U530555A5
FUNCTIONAL DESCRIPTION
Interface to external controller
The example of the interface between the NJU7505A and the external controller is shown below;
(1) Example of the interface to the external controller ( Using the single )
After the RSTb signal from the external controller is input and then the internal circuit is initialized, each
band data is output as shown below timing chart;
Since the RD signal is output before each band is switched, the external controller is to count the number of
the RD signal and is to recognize the status of the band and is to read the output data from the AOUT terminal
through the external A/D converter.
The output type of the external controller connected to the RSTb/CLKO terminal as the RSTb input should
be the N-channel and open-drain type or the diode should be connected between the RSTb/CLKO terminal
and the output terminal of the external controller, so that the voltage of the RSTb/CLKO terminal is not gotten
over the VSS level.
AIN
OSC1
A/D
Converter
NJU7505A
AOUT
OSC2
fOSC
RSTb/
CLKO
RD
VSS
µ CON
AOUT
RD
RSTb
f1
f1
f2
f2
3 x 214 / fosc
f3 f5 f1
f3 f5 f1
f2 f4 f3 f1
f2 f4 f3
f1
f1
f2
f2
f3
Since the RD signal is output before 248/fOSC
of each band switched, the output data should
be read out within the limited time as shown
right;
AOUT
RD
Available Period
of Read-out
248 / fOSC
8 / fOSC
If the RSTb signal which pulse width is
more than 4/fOSC is input, the internal circuit is
initialized and the data of f1 band is output from
the AOUT terminal after 52/fOSC of the rise edge
of the RSTb signal.
AOUT
fn
4 / fOSC[MIN]
RSTb
52 / fOSC
f1
Ver.2008-07-30
-3-







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