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Regulator ICs
System power supply for car stereos
BA3915B
The BA3915B is an one-chip power supply IC for use in car audio systems. The IC has seven output systems : one 5V output (VDD), four 8.5V outputs (COM, FM, AM, AR), and two high-side switch outputs (ANT, AMP). The 5V outputs operate all the time if only the BCAD input is provided. The other outputs operate with BACKUP and ACC inputs, and their ON / OFF is controlled by the STANDBY and MODE inputs. FApplications Car audio systems FFeatures 1) ACC and BACKUP voltages are monitored, compared with the internally set values; one-shot pulses are output to MUTE, which synchronizes with the rising and falling of the STANDBY input. 2) ACC voltage is monitored, compared with the internally set value, and the result is output to ACCB. 3) All outputs use a PNP transistor with low saturation voltage. FAbsolute maximum ratings (Ta = 25_C)
4) Output current limit circuit prevents damage to the IC due to short-circuiting. 5) Overvoltage protection circuit provides protection against surges from the ACC or BACKUP input. 6) Compact 16-pin POWER package allows large power dissipation.
FRecommended operating conditions (Ta = 25_C)
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FBlock diagram
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FPin descriptions (Ta = 25_C, BACKUP / ACC = 13.2V)
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FInput / output circuits
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FElectrical characteristics (unless otherwise noted, Ta = 25_C, BACKUP / ACC = 13.2V)
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FMeasurement circuits
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FInput / output timing chart
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FMUTE timing chart
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FAM / FM output timing chart
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FEstimate of allowable power dissipation Except under transitional conditions, the power dissipation of this IC is 3.4W per unit at 25_C. See Fig. 4 for heat reduction characteristics, including some cases where heat sinks are used.
A = maximum BACKUP voltage B = maximum BCAP voltage I1 = maximum output current for VDD (80mA) I2 = maximum output current for COM (300mA) I3 = maximum output current for FM (300mA) I4 = maximum output current for AM (200mA) I5 = maximum output current for AR (200mA) I6 = maximum output current for ANT (250mA) I7 = maximum output current for AMP (100mA) S Power consumed by VDD 5.0V S Power consumed by COM 8.5V S Power consumed by FM 8.5V S Power consumed by AM 8.5V S Power consumed by AR 8.5V S Power consumed by ANT S Power consumed by AMP S Power consumed internally by each circuit P1 = (B * 5.0V) I1 ) (I1 / 16 ) I1 / 10) I2 ) (I2 / 60 ) I2 / 10) P2 = (A * 8.5V) I3 ) (I3 / 60 ) I3 / 10) P3 = (A * 8.5V) I4 ) (I4 / 40 ) I4 / 10) P4 = (A * 8.5V) I5 ) (I5 / 40 ) I5 / 10) P5 = (A * 8.5V) I6 ) (I6 / 50 ) I6 / 10) A P6 = (0.6V) P7 = (0.6V) I7 ) (I7 / 50 ) I7 / 10) A circuit current (about 10mA) P8 = A B A A A A
P.