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Audio ICs
Low-current audio headphone driver
BA3575FS
The BA3575FS is a headphone driver with an AVC circuit that keeps the output below a fixed level. It features low current
consumption, and low output noise, and is ideal for use in portable digital audio equipment.
Applications
Portable CD players
Features
1) Low current consumption (when VCC = 2.4 V, the
quiescent current is 4.9mA).
2) Suitable for use in digital audio equipment (voltage
gain: GV = 11.8dB, output noise voltage: VNO =
–102dBm typ.).
3) ATT circuit (gain switch).
4) AVC (Auto Volume Control) circuit, for output limiting.
5) Internal standby switch.
6) Internal mute switch.
7) Internal ripple filter.
8) No output coupling capacitor required.
9) Internal beep circuit.
10) SSOP-A20 package.
Absolute maximum ratings (Ta = 25C)
Recommended operating conditions (Ta = 25C)
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Audio ICs BA3575FS
Block diagram
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Audio ICs BA3575FS
Pin descriptions
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Audio ICs BA3575FS
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Audio ICs BA3575FS
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Audio ICs BA3575FS
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Audio ICs BA3575FS
Electrical characteristics(unless otherwis noted, Ta = 25C, VCC = 2.4V, RL = 16Ω, f = 1kHz, DIN AUDIO,
PWSW = ON, MUTE = OFF, ATT = OFF, and AVC = OFF)
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Audio ICs BA3575FS
Measurement circuit
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Audio ICs BA3575FS
Measurement circuit switch table (Fig.1)
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Audio ICs BA3575FS
Application example
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Audio ICs BA3575FS
Application notes
(1) “Pop” sound
By operating the BA3575FS according to the timing chart shown in Fig.3, it is possible to suppress generation of “pop”
noise in the headphone output.
(2) Application circuits
Provided the recommended circuit constants are used,
the application circuits should function correctly . Howev-
er, we recommend that you confirm the characteristics of
the circuits in actual use. If you change the circuit
constants, check both the static and transient character-
istics of the circuit, and allow sufficient margin to accom-
modate variations between both ICs and external com-
ponents.
In particular, the capacitors connected to the OUT 1,
OUT 2, and VREF pins must have low impedance at high
frequency, and have sufficient margin in their tempera-
ture characteristics.
Also, use an electrolytic or tantalum capacitor for the ca-
pacitor connected to the BIASOUT terminal.
(3) The PCB pattern for the external components
should be designed carefully to prevent oscillation and
degradation of the circuit characteristics. Keep the wiring
tracks as short as possible, and ensure that there is no
impedance between the common connections.
The ripple filter pins (1 and 2) and the bias amplifier pins
(3 and 4) cannot be used for external power supplies or
reference voltages.
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Audio ICs BA3575FS
(4) Recommended operating conditions
The curves in Fig.4 below show the maximum allowable
power output (PO (Max.)/ch) plotted against the supply volt-
age (VCC) for different values of ambient temperature
(Ta). When VCC 3.6 V, operate the IC in the region be-
low the dotted line, and do not exceed it.
If the maximum allowable power output for each channel
(PO (Max.)/ch) is exceeded, the internal power consump-
tion will exceed the power dissipation capacity of the
package, and destroy the IC.
Electrical characteristics curves
External dimensions (Units: mm)
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Audio ICs BA3575FS