Nexperia

NCR420PAS / NCR421PAS

150 mA LED driver in DFN2020D-6

7. Thermal characteristics

Table 7. Thermal characteristics

Symbol Parameter

Conditions

Min

Typ

Max

Unit

[1] -

-

338

K/W

[2] -

-

219

K/W

[3] -

-

236

K/W

Rth(j-a)

thermal resistance from

junction to ambient

in free air

[4] -

-

179

K/W

[1] Device mounted on an FR4 PCB, single-sided copper, tin-plated and standard footprint.

[2] Device mounted on an FR4 PCB, single-sided copper, tin-plated; mounting pad for collector 1 cm2.

[3] Device mounted on an FR4 PCB, 4-layer copper, tin-plated and standard footprint.

[4] Device mounted on an FR4 PCB, 4-layer copper, tin-plated; mounting pad for collector 1 cm2.

006aad166

10-5

10

10-2

10-4

102

10-1

tp (s)

10-3

103

1

102

10

103

Zth(j-a)

(K/W)

1

duty cycle = 1

0.75

0.5

0.33

0.2

0.1

0.05

0.02

0.01

0

FR4 PCB; single-sided copper; tin-plated and standard footprint

Fig. 2. Transient thermal impedance from junction to ambient as a function of pulse duration; typical values

006aad167

10-5

10

10-2

10-4

102

10-1

tp (s)

10-3

103

1

102

10

103

Zth(j-a)

(K/W)

1

duty cycle = 1

0.75

0.5

0.33

0.2

0.1

0.05

0.02

0.01

0

FR4 PCB; mounting pad for collector 1 cm2

Fig. 3. Transient thermal impedance from junction to ambient as a function of pulse duration; typical values

NCR420PAS_NCR421PAS

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Nexperia B.V. 2020. All rights reserved

Product data sheet

Rev. 1 — 13 May 2020

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