Regulator ICs
Reference voltage power supply
The BA3933 is a monolithic reference voltage power supply IC for use in CD radio cassette players.
CD radio cassette players, mini-component stereo audio systems
1) With 7.5V output for audio power supply, 5V output
for microcontrollers, 5V output for radio 5 and 7.5V
outputs for CD players, 9V output for motor drivers,
the IC is best suited for CD radio cassette players.
2) Precise power supply (5V ± 0.1V) can be obtained by
using external reference voltage input (only AUDIO
output has an internal reference voltage system).
Absolute maximum ratings (Ta = 25C)
Recommended operating conditions (Topr = 25C)
3) Zero standby current. (Typ.)
4) Output current limit circuit protects the IC against
short-circuiting damage.
5) Compact SIP-M12 package allows a large power dissipation (3W: no heat sink).
6) Thermal protection circuit prevents heat damage to
the IC.
Regulator ICs
Block diagram
Pin descriptions
Regulator ICs
Input / output circuits
Regulator ICs
Electrical characteristics (unless otherwise noted, Ta = 25C and VCC = 16.0V)
Regulator ICs
Circuit operation
(1) Timing chart
(2) Estimate of allowable power dissipation
Except under transitional conditions, the power dissipation of this IC is 3W per unit at 25C. See Fig. 1 for thermal derating characteristics, including some cases
where heat sinks are used.
Thermal derating characteristics
AUDIO 7.5V, MOTOR 9V, and COM 5V are output regardless of MODE SW.
RADIO 5V rises when MODE SW is 1.4V (typical), and
CD 5V rises when MODE SW is 3.2V (typical).
Regulator ICs
Calculation of PMAX
Power consumed by AUDIO 7.5V
P1 = (VCC 7.5V)I1
Power consumed by MOTOR 9V
P2 = (VCC 9V)I2
Power consumed by CD 7.5V
P3 = (VCC 7.5V)I3
Power consumed by CD 5.0V
P4 = (VCC 5V)I4
Power consumed by RADIO 5.0V
P5 = (VCC 5V)I5
Power consumed by COM 5.0V
P6 = (VCC 5V)I6
Power consumed internally by each circuit
P7 = VCCcircuit current
I1 = maximum output for AUDIO 7.5V
I2 = maximum output for MOTOR 9V
I3 = maximum output for CD 7.5V
I4 = maximum output for CD 5V
I5 = maximum output for RADIO 5V
I6 = maximum output for COM 5V
Regulator ICs
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, characteristic 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 power 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 capacitor 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 recommend using a tantalum electrolytic capacitor having a capacitance of 10µF or greater (100µF or greater for AUDIO 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 (220µF or greater recommended) to the C pin
(pin 2).
(4) Overcurrent protection circuit
An overcurrent protection circuit is installed on 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) 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 restricted and latching will be prevented even if alarge current 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 continuously under transitional conditions (for instance, if output
is clamped at 1VF or higher, short mode circuit operates
at 1VF or lower).
(5) Reference voltage
Because output voltage is dependent on the input reference voltage, unstable input results in output wavering
and degradation of ripple rejection. Take care when setting 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 adequately 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 prevents electric interference.
Electrical characteristic curve
External dimensions (Units: mm)