BD9763FVM Datasheet, PDF (9/12 Pages) Rohm – Single-output Step-up,High-efficiency Switching Regulator (Controller Type)

BD9763FVM
Technical Note
●Operation Notes
(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 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 then 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 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 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 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.
Bypass diode
Back current prevention diode
VCC
Output pin
Fig.13
(10) Timing resistor
Timing resistor connected between RT and GND, has to be placed near RT terminal (8pin).
And pattern has to be short Enough.
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2009.05 - Rev.A