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Technical Note

BH

□□FB1WG series, BH□□FB1WHFV series,

BH

□□LB1WG series, BH□□LB1WHFV series,

BH

□□MA3WHFV series

It is recommended to insert bypass capacitors between input and GND pins, positioning them as close to the pins as

possible. These capacitors will be used when the power supply impedance increases or when long wiring routes are used, so

they should be checked once the IC has been mounted.

Ceramic capacitors generally have temperature and DC bias characteristics. When selecting ceramic capacitors, use X5R or

X7R or better models that offer good temperature and DC bias characteristics and high torelant voltages.

Input capacitor

To prevent oscillation at the output, it is recommended that the IC be operated at the stable region show in below Fig. It

operates at the capacitance of more than 1.0

μF. As capacitance is larger, stability becomes more stable and characteristic of

output load fluctuation is also improved.

Output capacitor

Examples of ceramic capacitor characteristics

0

120

100

80

60

40

20

0

1234

50V torelance

10V torelance

DC bias Vdc (V)

-25

120

100

80

60

40

20

0

0

255075

Y5V

X7R

X5R

Temperature (

°C)

0

100

95

90

85

80

75

70

1234

50V torelance

10V torelance

16V torelance

DC bias Vdc (V)

Fig. 29: Capacitance -bias characteristics (Y5V)

Fig. 30: Capacitance -bias characteristics (X5R, X7R)

Fig. 31: Capacitance–temperature characteristics

(X5R, X7R, Y5V)

100

10

1

0.1

0.01

0

100

200

300

Cout=1.0

μF

Cin=1.0

μF

Ta=+25

°C

BH

LB1WHFV/WG

BH

MA3WHFV

Fig. 32 BH

LB1WHFV/WG

Stable operating region characteristics (Example)

100

10

1

0.1

0.01

0

50

100

150

Cout=1.0

μF

Ta=+25

°C

BH

FB1WHFV/WG

Fig. 33 BH

FB1WHFV/WG

Stable operating region characteristics (Example)

100

10

1

0.1

0.01

0

50

100

150

Cout=2.2

μF

Ta=+25

°C

Stable region

Stable region

Stable region

The IC incorporates a built-in over current protection circuit that operates according to the output current capacity. This circuit

serves to protect the IC from damage when the load is shorted. The protection circuits use fold-back type current limiting and

are designed to limit current flow by not latching up in the event of a large and instantaneous current flow originating from a

large capacitor or other component. These protection circuits are effective in preventing damage due to sudden and

unexpected accidents. However, the IC should not be used in applications characterized by the continuous operation or

transitioning of the protection circuits.

• Over current protection circuit

This system has a built-in thermal shutdown circuit for the purpose of protecting the IC from thermal damage. As shown

above, this must be used within the range of power dissipation, but if the power dissipation happens to be continuously

exceeded, the chip temperature increases, causing the thermal shutdown circuit to operate. When the thermal shutdown

circuit operates, the operation of the circuit is suspended. The circuit resumes operation immediately after the chip

temperature decreases, so the output repeats the ON and OFF states. There are cases in which the IC is destroyed due to

thermal runaway when it is left in the overloaded state. Be sure to avoid leaving the IC in the overloaded state.

• Thermal shutdown circuit

Other precautions

Use caution when using the IC in the presence of a strong magnetic field as such environments may occasionally cause the chip

to malfunction.

• Actions in strong magnetic fields

In applications where the IC may be exposed to back current flow, it is recommended to create a route t dissipate this current

• Back current

Ensure a minimum GND pin potential in all operating conditions.

In addition, ensure that no pins other than the GND pin carry a voltage less than or equal to the GND pin, including during

actual transient phenomena.

• GND potential

Fig. 34 BH

MA3WHFV

Stable operating region characteristics (Example)

16V torelance

2010.07 -

Rev. C

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