Technical Note

10/11

BD1754HFN

www.rohm.com

2011.06 - Rev.B

© 2011 ROHM Co., Ltd. All rights reserved.

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Notes for Use

(1) Absolute Maximum Ratings

An excess in the absolute maximum ratings, such as applied voltage, temperature range of operating conditions, can

break down devices, thus making impossible to identify breaking mode such as a short circuit or an open circuit. If any

special mode exceeding the absolute maximum ratings is assumed, consideration should be given to take physical

safety measures including the use of fuses, etc.

(2) Recommended Operating Conditions

These conditions represent a range within which characteristics can be provided approximately as expected. The

electrical characteristics are guaranteed under the conditions of each parameter. The voltage and temperature

characteristics are also shown under the conditions in respect of electrical ones.

(3) Reverse connection of power supply connector

The reverse connection of power supply connector can break down ICs. Take protective measures against the breakdown

due to the reverse connection, such as mounting an external diode between the power supply and the IC’s power

supply terminal.

(4) Power supply line

Design PCB pattern to provide low impedance for the wiring between the power supply and the GND lines.

Furthermore, for all power supply terminals to ICs, mount a capacitor between the power supply and the GND terminal.

At the same time, in order to use an electrolytic capacitor, thoroughly check to be sure that the characteristics of the

capacitor to be used present no problem including the occurrence of capacity dropout at a low temperature, thus

determining the constant.

(5) GND voltage

Make setting of the potential of the GND terminal so that it will be maintained at the minimum in any operating state.

Furthermore, check to be sure that no terminal is operated at a potential lower than the GND voltage including an

actual electric transient.

(6) Short circuit between terminals and erroneous mounting

In order to mount ICs on a set PCB, pay thorough attention to the direction and offset of the ICs. Erroneous mounting

can break down the ICs. Furthermore, if a short circuit occurs due to foreign matters entering between terminals or

between the terminal and the power supply or the GND terminal, the ICs can break down.

(7) Operation in strong electromagnetic field

Be noted that using ICs in the strong electromagnetic field can cause a malfunction.

(8) Inspection with set PCB

On the inspection with the set PCB, if a capacitor is connected to a low-impedance IC terminal, the IC can suffer stress.

Therefore, be sure to discharge from the set PCB by each process. Furthermore, in order to mount or dismount the set

PCB to/from the jig for the inspection process, be sure to turn OFF the power supply and then mount the set PCB to

the jig. After the completion of the inspection, be sure to turn OFF the power supply and then dismount it from the jig. In

addition, for protection against static electricity, establish a ground for the assembly process and pay thorough attention

to the transportation and the storage of the set PCB.

(9) Input terminals

In terms of the construction of IC, parasitic elements are inevitably formed in relation to potential. The operation of the

parasitic element can cause interference with circuit operation, thus resulting in a malfunction and then breakdown of

the input terminal. Therefore, pay thorough attention not to handle the input terminals, such as to apply to the input

terminals a voltage lower than that applied to the GND respectively, so that any parasitic element will operate.

Furthermore, do not apply a voltage to the input terminals when no power supply voltage is applied to the IC. In

addition, even if the power supply voltage is applied, apply to the input terminals a voltage lower than the power supply

voltage or within the guaranteed value of electrical characteristics.

(10) Ground wiring pattern

If small-signal GND and large-current GND are provided, it will be recommended to separate the large-current GND

pattern from the small-signal GND pattern and establish a single ground at the reference point of the set PCB so that

resistance to the wiring pattern and voltage fluctuations due to a large current will cause no fluctuations in voltages of

the small-signal GND. Pay attention not to cause fluctuations in the GND wiring pattern of external parts as well.

(11) Thermal design

Perform thermal design in which there are adequate margins by taking into account the permissible dissipation (Pd) in actual

states of use.