BD9853AFV

Technical Note

14/16

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2009.05 - Rev.A

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Output Pin

VCC

Back current prevention diode

Bypass diode

●

Notes for use

1) Absolute maximum ratings

Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range may

result in IC deterioration or damage. Assumptions should not be made regarding the state of the IC (short mode or open

mode) when such damage is suffered. A physical safety measure such as a fuse should be implemented when use of the

IC in a special mode where the absolute maximum ratings may be exceeded is anticipated.

2) GND potential

Ensure a minimum GND pin potential in all operating conditions. In addition, ensure that no pins other than the GND pin

carry a voltage lower than or equal to the GND pin, including during actual transient phenomena.

3) Thermal design

Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions.

4) Inter-pin shorts and mounting errors

Use caution when orienting and positioning the IC for mounting on printed circuit boards. Improper mounting may result in

damage to the IC. Shorts between output pins or between output pins and the power supply and GND pin caused by the

presence of a foreign object may result in damage to the IC.

5) Operation in a strong electromagnetic field

Use caution when using the IC in the presence of a strong electromagnetic field as doing so may cause the IC to

malfunction.

6) Thermal shutdown circuit (TSD circuit)

This IC incorporates a built-in thermal shutdown circuit (TSD circuit). The TSD circuit is designed only to shut the IC off to

prevent runaway thermal operation. Do not continue to use the IC after operating this circuit or use the IC in an

environment where the operation of the thermal shutdown circuit is assumed.

7) Testing on application boards

When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to stress.

Always discharge capacitors after each process or step. Ground the IC during assembly steps as an antistatic measure,

and use similar caution when transporting or storing the IC. Always turn the IC's power supply off before connecting it to or

removing it from a jig or fixture during the inspection process.

8) Common impedance

Power supply and ground wiring should reflect consideration of the need to lower common impedance and minimize ripple

as much as possible

(by making wiring as short and thick as possible or rejecting ripple by incorporating inductance and capacitance).

9) Applications with modes that reverse VCC and pin potentials may cause damage to internal IC circuits.

For example, such damage might occur when VCC is shorted with the GND pin while an external capacitor is charged.

It is recommended to insert a diode for preventing back current flow in series with VCC or bypass diodes between VCC

and each pin.

10) Pin short and mistake fitting

Do not short-circuit between OUT pin and VCC pin, OUT pin and GND pin, or VCC pin and GND pin.

When soldering the IC on circuit board,

please be unusually cautious about the orientation and the position of the IC.

11) Timing resistor and capacitor

Timing resistor connected between RT and GND, has to be placed near RT terminal. And pattern has to be short enough.