Communication ICs
Speech network for telephones
BA6569AS / BA6569AFP
The BA6569AS and BA6569AFP are speech networks which possesses the basic functions required for handset communications. In addition to amplifying signals from a transmitter and sending them to a telephone line, they also amplify
only reception signals from a telephone line and drive the receiver. In addition to a function which compensates for fluctuation in the transmission and reception volume caused by the length of the telephone line (AGC), they are also
equipped with a manual PAD function in order to accommodate PBX.
FApplications
Telephones and telephone equipment
FFeatures
1) Basic speech network functions built in.
2) Single output pin of reception pre-amplifier is separate.
3) Single input pin of reception pre-amplifier is separate, enabling mixing of input.
4) Input to microphone pre-amplifier is balanced and offers high resistance to in-line noise.
5) Input pin of MF pre-amplifier enables mixing of input.
6) Manual pad pin included.
7) Pre-amplifiers for reception, microphone, and MF
employ AGC based on telephone line current.
8) AC impedance can be raised by altering the positive feedback. This enables configuration of power
supply circuits for microcomputers and other applications using only a single resistor.
9) A BTL circuit is used for reception output, and the
wide dynamic range enables both dynamic and ceramic receivers to be accommodated.
10) Few external attachments are required.
11) 22-pin SDIP and 24-pin HSOP packages available.
FAbsolute maximum ratings (Ta = 25_C)
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Communication ICs BA6569AS / BA6569AFP
Block diagram
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Communication ICs BA6569AS / BA6569AFP
FElectrical characteristics (unless otherwise noted, Ta = 25_C, f = 1kHz, BPF = 400Hz to 30kHz)
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Communication ICs BA6569AS / BA6569AFP
Electrical characteristic curves
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Communication ICs BA6569AS / BA6569AFP
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Communication ICs BA6569AS / BA6569AFP
Measurement circuits
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Communication ICs BA6569AS / BA6569AFP
Circuit operation
The BA6569AS and BA6569AFP carry out the following
basic operations.
(1) Handset talk and receive
Voice signals received from a telephone line are output
to a handset speaker. V oice signals from the handset microphone are also output to the telephone line.
(2) DTMF send and key tone input
The BA6569AS and BA6569AFP have a mute switch
which can be switched between a “handset send and receive” mode and a “DTMF send and key tone input”
mode by an external logic signal. In the “DTMF send and
key tone input” mode, it transmits DTMF signals from the
dial pad to the telephone line, and key tones to the handset receiver.
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(3) AGC
Gain is adjusted steplessly in response to the size of current from the telephone line. When there is a large current (a short distance is involved), the gain is lowered.
The gain volume can also be adjusted by changing the
value of the resistor connected to the AGC pin.
(4) Manual pad
In order to accommodate situations such as a PBX,
where there is little current but a short distance is involved, the gain can be lowered by a constant volume regardless of the current value. Fluctuation in the amount
of gain can be adjusted by changing the value connected
to the MPAD pin.
Communication ICs BA6569AS / BA6569AFP
Pin descriptions
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Communication ICs BA6569AS / BA6569AFP
Operation notes
The maximum power dissipation for the BA6569AS is
1100mW, and for the BA6569AFP , the maximum power
dissipation is 1200mW (when mounted on 90mm
50mm 1.6mm glass epoxy boards, however, fins
should be soldered to the foil pattern). Since the maximum power dissipation varies with temperature, the
product of the applied voltage VL and the total current
drawn by the IC, after factoring in the temperature,
should not exceed the maximum dissipation.
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Communication ICs BA6569AS / BA6569AFP
Application example
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Communication ICs BA6569AS / BA6569AFP
Application board pattern
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Communication ICs BA6569AS / BA6569AFP
Application board component layout
External dimensions (Units: mm)
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