ROHM BA61W12ST

Regulator ICs
Dual output voltage regulator
with power saving
BA61W12ST
The BA61W12ST is a general-purpose, low saturation power supply with two outputs : 10V, 1A and 5V, 500mA. The
IC is available in a compact TO220FP-5 package. The outputs can be turned off during the power saving state with the
built-in switch. Also built in the IC are an overcurrent protection circuit, an overvoltage protection circuit, and a thermal
shutdown circuit.
Applications
Car audio systems, VCRs, facsimiles, air conditioners, and other household and industrial equipment
Features
1) Minimum I / O voltage differential is 0.5V or less.
2) Built-in protection circuits against overcurrent, overvoltage, and overheat.
3) Available in a compact TO220FP-5 package (pins
are bendable).
4) Zero power saving current. (Typ.)
Block diagram
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Regulator ICs
FAbsolute maximum ratings (Ta = 25_C)
FRecommended operating conditions (Ta = 25_C)
FPin descriptions
FInput / output circuits
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BA61W12ST
Regulator ICs
BA61W12ST
FElectrical characteristics (unless otherwise noted, Ta = 25_C and VCC = 15.0V)
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Regulator ICs
Measurement circuits
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BA61W12ST
Regulator ICs
BA61W12ST
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Regulator ICs
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BA61W12ST
Regulator ICs
BA61W12ST
Application example
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Regulator ICs
Operation notes
(1) The application circuit of Fig.8 is recommended for
use. Make sure to confirm the adequacy of parts characteristics. When using the circuit with changes to external
circuit constants, make sure to leave sufficient margins
in consideration of fluctuations in the IC and external
components including static and transitional characteristics. Note that ROHM has not carried out extensive survey regarding the patent right of this application.
(2) Operating power supply voltage
When operating within the 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.
(3) Power dissipation (Pd)
Refer to the power dissipation characteristics in Fig. 10.
If power dissipation exceeds the allowable limit, the functionality of the IC will be degraded (such as reduction of
current capacity by increased chip temperature). Make
sure to use the IC within the allowable range of power dissipation with a sufficient margin.
(4) Preventing oscillation at each output and bypass
capacitor
To stop output oscillation, make sure to connect a capacitor between GND and each output pin (capacitance of at
least 10 µF over the whole operating temperature range
is recommended). Oscillation can occur if capacitance is
susceptible to temperature. We recommend using a tantalum electrolytic capacitor with minimal changes in capacitance. Also, output can be further stabilized by connecting a bypass capacitor of about 0.33 µF between the
input pin and GND. Place the capacitor as near as possible to the input pin.
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BA61W12ST
(5) Overcurrent protection circuit
An overcurrent protection circuit is installed in each output system, based on the respective output current. This
prevents IC destruction due to 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 a large 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). Note that the circuit ability is negatively correlated with temperature.
(6) Thermal protection circuit
A built-in thermal protection circuit prevents thermal
damage to the IC. All outputs are turned off when the circuit operates, and revert to the original state when the
temperature drops to a certain level.
(7) We recommend installing a bypass line with a diode
in your application if there is a mode where potential difference between each output and input (VCC) or GND is
reversed from the normal state. A reversed mode may
cause damage to the IC.
(8) Although the quality of this IC is rigorously controlled, the IC may be destroyed when the applied voltage or the operating temperature exceeds its absolute
maximum rating. Because short mode or open mode
cannot be specified when the IC is destroyed, be sure to
take physical safety measures, such as fusing, if any of
the absolute maximum ratings might be exceeded.
(9) When used within a strong magnetic field, be aware
that there is a slight possibility of malfunction.
Regulator ICs
BA61W12ST
Electrical characteristic curves
External dimensions (Units: mm)
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