TA7818S 查看數據表（PDF） - Toshiba

零件编号

产品描述 (功能)

生产厂家

TA7818S

Three Terminal Positive Voltage Regulators

Toshiba 

TA7805,057,06,07,08,09,10,12,15,18,20,24S

Precautions on Application

(1) In regard to GND, be careful not to apply a negative voltage to the input/output terminal. Further,

special care is necessary in case of a voltage boost application.

(2) When a surge voltage exceeding maximum rating is applied to the input terminal or when a voltage

in excess of the input terminal voltage is applied to the output terminal, the circuit may be destroyed.

Specially, in the latter case, great care is necessary.

Further, if the input terminal shorts to GND in a state of normal operation, the output terminal

voltage becomes higher than the input voltage (GND potential), and the electric charge of a chemical

capacitor connected to the output terminal flows into the input side, which may cause the destruction

of circuit.

In these cases, take such steps as a zener diode and a general silicon diode are connected to the circuit,

as shown in the following figure.

(3) When the input voltage is too high, the power dissipation of three terminal regulator increases

because of series regulator, so that the junction temperature rises. In such a case, it is recommended

to reduce the power dissipation by inserting the power limiting resistor RSD in the input terminal,

and to reduce the junction temperature as a result.

The power dissipation PD of IC is expressed in the following equation.

If VIN' is reduced below the lowest voltage necessary for the IC, the parasitic oscillation will be caused

according to circumstances.

In determing the resistance value of RSD, design with margin should be made by making reference to

the following equation.

(4) Connect the input terminal and GND, and the output terminal and GND, by capacitor respectively.

The capacitances should be determined experimentally because they depend on PCB patterns. In

particular, adequate investigation should be made so that there is no problem even at time of high or

low temperature.

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2003-01-29

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