Rainbow Electronics BA3933 - Manual (Page 7)

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External dimensions (Units: mm)
166
Regulator ICs BA3933
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Operation notes
(1) Operating power supply voltage
When operating within proper ranges of power supply
voltage and ambient temperature, most circuit functions
are guaranteed. Although the rated values of electrical
characteristics cannot be absolutely guaranteed, char-
acteristic values do not change drastically within the
proper ranges.
(2)
Power dissipation (Pd)
Refer to the heat reduction characteristics and the rough
estimation of IC power dissipation given on a separate
pages. Make sure to use the IC within the allowable pow-
er dissipation with a sufficient margin.
(3)
Preventing oscillation at each output and installing
a ripple filter capacitor.
To stop oscillation of output, make sure to connect a ca-
pacitor between GND and each of the AUDIO 7.5V (pin
1), RADIO (pin 4), COM (pin 5), CD 5V (pin 6), CD 7.5V
(pin 7), and MOTOR 9V (pin 11) output pins. We recom-
mend using a tantalum electrolytic capacitor having a ca-
pacitance of 10
µ
F or greater (100
µ
F or greater for AU-
DIO 7.5V) with minimal temperature susceptibility. Also,
sudden deterioration of the AUDIO 7.5V ripple rejection
during a power drop can be prevented by connecting a
capacitor (220
µ
F or greater recommended) to the C pin
(pin 2).
(4)
Overcurrent protection circuit
An overcurrent protection circuit is installed on the AU-
DIO 7.5V (pin 1), RADIO (pin 4), COM (pin 5), CD 5V (pin
6), CD 7.5V (pin 7), and MOTOR 9V (pin 11) outputs,
based on the respective output current. This prevents IC
destruction by overcurrent, by limiting the current with a
curve shape of “7” in the voltage-current graph. The IC
is designed with margins so that current flow will be re-
stricted and latching will be prevented even if alarge cur-
rent suddenly flows through a large capacitor. Note that
these protection circuits are only good for preventing
damage from sudden accidents. Make sure your design
does not cause the protection circuit to operate continu-
ously under transitional conditions (for instance, if output
is clamped at 1V
F
or higher, short mode circuit operates
at 1V
F
or lower).
(5) Reference voltage
Because output voltage is dependent on the input refer-
ence voltage, unstable input results in output wavering
and degradation of ripple rejection. Take care when set-
ting the reference voltage power supply. Note that the
AUDIO output, which has a built-in reference voltage
system, is not affected by the external reference voltage.
(6)
Thermal protection circuit
A built-in thermal protection circuit prevents thermal
damage to the IC. All outputs are switched OFF when the
circuit operates, and revert to the original state when
temperature drops to a certain level.
(7)
Grounding
Each ground line in the application circuit must be ade-
quately short regarding the PREGND (pin 3) and GND
(pin 12) pins. Make sure to arrange the ground lines, the
AUDIO system, and other outputs in a pattern that pre-
vents electric interference.
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Electrical characteristic curve