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 127 Regulator ICs FAbsolute maximum ratings (Ta = 25_C) FRecommended operating conditions (Ta = 25_C) FPin descriptions FInput / output circuits 128 BA61W12ST Regulator ICs BA61W12ST FElectrical characteristics (unless otherwise noted, Ta = 25_C and VCC = 15.0V) 129 Regulator ICs Measurement circuits 130 BA61W12ST Regulator ICs BA61W12ST 131 Regulator ICs 132 BA61W12ST Regulator ICs BA61W12ST Application example 133 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. 134 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) 135