BA3933D [ROHM]
Fixed Positive Standard Regulator, 5VPSFM12, SIP-12;
| 型号： | BA3933D |
| 厂家： | 
ROHM |
| 描述： | Fixed Positive Standard Regulator, 5VPSFM12, SIP-12 模拟IC 信号电路 |
| 文件： | 总7页 (文件大小：135K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Regulator ICs
Reference voltage power supply
BA3933
The BA3933 is a monolithic reference voltage power supply IC for use in CD radio cassette players.
FApplications
CD radio cassette players, mini-component stereo audio systems
FFeatures
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).
3) Zero standby current. (Typ.)
4) Output current limit circuit protects the IC against
short-circuiting damage.
5) CompactSIP-M12packageallowsalargepowerdis-
sipation (3W: no heat sink).
6) Thermal protection circuit prevents heat damage to
the IC.
FAbsolute maximum ratings (Ta = 25_C)
FRecommended operating conditions (Topr = 25_C)
160
Regulator ICs
BA3933
FBlock diagram
FPin descriptions
161
Regulator ICs
BA3933
FInput / output circuits
162
Regulator ICs
BA3933
FElectrical characteristics (unless otherwise noted, Ta = 25_C and VCC = 16.0V)
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Regulator ICs
BA3933
FCircuit operation
(1) Timing chart
(2) Estimate of allowable power dissipation
Except under transitional conditions, the power dissipa-
tion of this IC is 3W per unit at 25_C. See Fig. 1 for ther-
mal derating characteristics, including some cases
where heat sinks are used.
FThermal derating characteristics
AUDIO 7.5V, MOTOR 9V, and COM 5V are output re-
gardless of MODE SW.
RADIO 5V rises when MODE SW is 1.4V (typical), and
CD 5V rises when MODE SW is 3.2V (typical).
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Regulator ICs
BA3933
Calculation of PMAX
S Power consumed by AUDIO 7.5V
P1 = (VCC * 7.5V) I1
S Power consumed by MOTOR 9V
P2 = (VCC * 9V) I2
S Power consumed by CD 7.5V
P3 = (VCC * 7.5V) I3
S Power consumed by CD 5.0V
P4 = (VCC * 5V) I4
S Power consumed by RADIO 5.0V
P5 = (VCC * 5V) I5
S Power consumed by COM 5.0V
P6 = (VCC * 5V) I6
S Power consumed internally by each circuit
P7 = VCC circuit 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
165
Regulator ICs
BA3933
FOperation notes
(1) Operating power supply voltage
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 1VF or higher, short mode circuit operates
at 1VF or lower).
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.
(5) Reference voltage
(3) Preventing oscillation at each output and installing
a ripple filter capacitor.
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
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 10µF or greater (100µF 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 (220µF or greater recommended) to the C pin
(pin 2).
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.
(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
FElectrical characteristic curve
FExternal dimensions (Units: mm)
166
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