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BA6901F

Datasheet

Datasheet

TSZ02201-0H1H0B100500-1-2

© 2012 ROHM Co., Ltd. All rights reserved.

18.DEC.2012 Rev.002

TSZ22111・15・001

www.rohm.com

●Power dissipation

Power dissipation (total loss) indicates the power that can be consumed by IC at Ta = 25ºC (normal temperature). IC is

heated when it consumes power, and the temperature of IC chip becomes higher than ambient temperature. The

temperature that can be accepted by IC chip depends on circuit configuration, manufacturing process, etc, and consumable

power is limited. Power dissipation is determined by the temperature allowed in IC chip (maximum junction temperature)

and thermal resistance of package (heat dissipation capability). The maximum junction temperature is in general equal to

the maximum value in the storage temperature range.

Heat generated by consumed power of IC is radiated from the mold resin or lead frame of package. The parameter which

indicates this heat dissipation capability (hardness of heat release) is called heat resistance, represented by the symbol θ

ja [℃/W]. The temperature of IC inside the package can be estimated by this heat resistance. Fig.19 shows the model of

heat resistance of the package.

Heat resistance

θja, ambient temperature Ta, junction temperature Tj, and power consumption P can be calculated by the

equation below:

Thermal derating curve indicates power that can be consumed by IC with reference to ambient temperature. Power that can

be consumed by IC begins to attenuate at certain ambient temperature. This gradient is determined by thermal resistance

θja.

Thermal resistance

θja depends on chip size, power consumption, package ambient temperature, packaging condition,

wind velocity, etc., even when the same package is used. Thermal derating curve indicates a reference value measured at

a specified condition. Fig.20 shows a thermal derating curve (Value when mounting FR4 glass epoxy board 70 [mm] x 70

[mm] x 1.6 [mm] (copper foil area below 3 [%]))

*Reduce by 5.0mW/°C over 25°C

(On 70.0mm x 70.0mm x 1.6mm glass epoxy board)

●I/O equivalence circuit(Resistance values are typical)

1) Hall input terminal

2) Current limiting input terminal

3) Charge-discharge pulse

Output current detecting terminal

output terminal

4) PWM input terminal

5) Output terminal

6) Signal output terminal

θja = (Tj – Ta) / P [°C/W]

Fig.19 Thermal resistance

Fig.20 Thermal de-rating curve

θja = (Tj – Ta) / P [°C/W]

Chip surface temperature Tj[°C]

Package surface temperature Tc[°C]

Power consumption P[W]

Ambient temperature Ta[°C]

Pd(mW)

700

600

560

500

400

300

200

100

025

50

75

100

125

150

Ta(℃)

95

625

BA6901F

800

H+

H-

Vcc

1kΩ

1kΩ

PWM

Vcc

1kΩ

30kΩ

100kΩ

GND

Vcc

A1, A2

15kΩ

FG、AL、ALB

CS

Vcc

CL

1kΩ

1kΩ

Vcc

TOUT

30Ω

30Ω

1kΩ