Audio ICs

Band-pass filter for spectral analyzers
BA3830S
The BA3830S is a 61 band band-pass filter for spectral analyzer displays with internal recording indicator output. Allof the capacitors comprising the filter are internal capacitors, making it possible to significantly reduce the number ofattached components. This enables configuration of compact sets with a high level of reliability.
Applications
CD radio cassette players, mini-components, car stereos

Features
1) Six internal band-pass filters for spectral analyzers
2) Internal input / output for recording indicators

3) Internal capacitors reduce the number of attachments.

Absolute maximum ratings (Ta = 25C)

Recommended operating conditions (Ta = 25C)

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Block diagram

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BA3830S

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BA3830SElectrical characteristics (unless otherwise noted, Ta = 25C, VCC = 5V, RL = 10MΩ, Rφ1 = 270kΩ,
Rφ2 = 270kΩ)

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Measurement circuit

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BA3830S

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Circuit operation(1) LINE and REC input circuits
The LINE and REC input circuits are configured as differential amplifiers, and the gain can be set to any desiredvalue using an external resistor. The input impedance isdetermined by the external resistor.

BA3830S(2) Bias circuit
A bias voltage of VCC / 2 is applied to each of the circuits.
Since the output stage uses a push-pull configuration, astable bias source can be obtained.

(3) BPF circuit
This is a circuit that selects the required frequency component from the input signal and amplifies it. With thisconfiguration, no external capacitor is needed. In addition, the center frequency is set based on the current, sof01 and f02 to f06 can be set individually, using separate external resistors (pins1 and 2).
Q is set to 4.5V (Typ.).

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Audio ICs(4) DET circuit
This circuit carries out phase detection on the signal selected and amplified by the BPF, and holds it at the peaklevel. It is configured so that all of the capacitors are internal.
The charge that was charged by the internal capacitors
in the DET circuit is set to be discharged at 75ms / V(Typ.), but in order to eliminate any effects of disparity, areset circuit is also included.

(5) Output section circuit
The signal level held at peak level by the DET undergoes
V / I conversion and is output. Since the next stage supports MOS (high-input impedance), there is a resistanceof 33.9kΩ (44.3kΩ for REC output only) between the output pin and the GND in the IC, so the output valuechanges based on the input impedance.

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BA3830S

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BA3830S

Application example

Operation notes(1) Precautions concerning the load resistance
The various characteristics were measured at the output
resistance value of 10MΩ noted in the specificationsmanual. Moreover, because the output of this IC supports the MOS configuration, be aware that it is current
output, and the output changes depending on the input
impedance at the next stage.
(2) Precautions concerning the RESET capacitor
If the reset function is to be used, a capacitor of at least
3300pF is required for RESET C (pin 7). Failing to connect this capacitor can result in erroneous displays, so
make sure a sufficient capacitance is provided.

(3) Precautions concerning the coupling capacitor
When determining the polarity of the input electrolytic
coupling capacitor, the potential relation with the otherend of the coupling must be taken into consideration.

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Electrical characteristic curves

External dimensions (Units: mm)

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BA3830S

This datasheet has been download from:www.datasheetcatalog.com
Datasheets for electronics components.