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– July 2021

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5.5 Thermal Information

Symbol

Description

Heater off, die

pad soldered

(K/W)

Heater on, die

pad soldered

(K/W)

Heater off, die

pad

not soldered

(K/W)

Heater on, die

pad

not soldered

(K/W)

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Junction-to-ambient

thermal resistance

246

308

297

357

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Junction-to-case

thermal resistance

189

255

191

257

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Junction-to-board

thermal resistance

159

225

193

258

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Junction-to-board

characterization

param.

159

223

191

254

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Junction-to-top

characterization

param.

38

105

44

112

Table 8 Typical

values for thermal metrics. In the “heater on” columns a heater power of 200 mW was

assumed. Soldering of the die pad is not recommended, therefore the two right hand side columns are bold.

Values are based on simulation.

6 Quality and Material Contents

Qualification of SHT4x is performed based on the JEDEC JESD47 qualification test method,

qualification report available on request. The device is fully RoHS and WEEE compliant, e.g. free

of Pb, Cd, and Hg.

For general remarks of best practice in processing humidity sensor please refer to the handling

instructions (Sensirion, 2020).

7 Tape and Reel Packaging

All specifications for the tape and reel packaging can be found on Figure 12. Reel diameters are

13 inch and 8 inch for the 10k and the 2.5k packaging sizes, respectively.

Figure 12: Tape and reel specifications including sensor orientation in pocket (see indication of two sensors

on the right side of the tape).