TLR342FVT datasheet(37/54 Pages) ROHM

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Datasheet

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TSZ02201-0RAR0G200720-1-2

37/51

03.Feb.2016 Rev.004

TSZ22111･15･001

TLR341G TLR342xxx TLR344xxx

Power Dissipation

Power dissipation (total loss) indicates the power that the IC can consume at TA=25°C (normal temperature). As the IC

consumes power, it heats up, causing its temperature to be higher than the ambient temperature. The allowable temperature

that the IC can accept is limited. This depends on the circuit configuration, manufacturing process, and consumable power.

Power dissipation is determined by the allowable temperature within the IC (maximum junction temperature) and the thermal

resistance of the package used (heat dissipation capability). Maximum junction temperature is typically equal to the

maximum storage temperature. The heat generated through the consumption of power by the IC radiates from the mold

resin or lead frame of the package. Thermal resistance, represented by the symbol θJA°C/W, indicates this heat dissipation

capability. Similarly, the temperature of an IC inside its package can be estimated by thermal resistance.

Figure 82(a) shows the model of the thermal resistance of a package. The equation below shows how to compute for the

Thermal resistance (θJA), given the ambient temperature (TA), maximum junction temperature (Tjmax), and power dissipation

(PD).

θJA = (Tjmax－TA) / PD

°C/W

The derating curve in Figure 82(b) indicates the power that the IC can consume with reference to ambient temperature.

Power consumption of the IC begins to attenuate at certain temperatures. This gradient is determined by Thermal resistance

(θJA), which depends on the chip size, power consumption, package, ambient temperature, package condition, wind velocity,

etc. This may also vary even when the same of package is used. Thermal reduction curve indicates a reference value

measured at a specified condition. Figure 82 (c), (d), and (e) shows an example of the derating curve for TLR341G,

TLR342xxx, and TLR344xxx, respectively.

0.0

0.2

0.4

0.6

0.8

1.0

100

125

150

Ambient Temperature [°C]

0.0

0.2

0.4

0.6

0.8

1.0

100

125

150

Ambient Temperature [°C]

(d) TLR342xxx

θJA=(Tjmax-TA)/ PD °C/W

Ambient Temperature TA [ °C ]

Chip Surface Temperature TJ [ °C ]

(a) Thermal Resistance

(b) Derating Curve

Ambient Temperature TA [ °C ]

Power Dissipation of LSI [W]

PDmax

θJA2 < θJA1

100

125

150

θJA2

θJA1

Tjmax

TLR342FJ

(Note 36)

TLR342FVT

(Note 37)

TLR342FVJ

(Note 38)

TLR342F

(Note 35)

TLR341G

(Note 34)

TLR342FVT Datasheet(PDF) 37 Page - Rohm

TLR342FVT Datasheet(HTML) 37 Page - Rohm

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