www.sensirion.com / D1

Version 1

– December 2022

21/26

5.3 Package Outline

Figure 6. Dimensional drawing of SHT33-DIS sensor package

Parameter

Symbol

Min

Nom.

Max

Units Comments

Package height

A

0.8

0.9

1

mm

Leadframe height

A3

-

0.2

-

mm

Pad width

b

0.2

0.25

0.3

mm

Package width

D

2.4

2.5

2.6

mm

Center pad length

D2

1

1.1

1.2

mm

Package length

E

2.4

2.5

2.6

mm

Center pad width

E2

1.7

1.8

1.9

mm

Pad pitch

e

-

0.5

mm

Pad length

L

0.25

0.35

0.45

mm

Max cavity

S

-

-

1.5

mm

Only as guidance. This value includes all

tolerances, including displacement tolerances.

Typically the opening will be smaller.

Center pad marking

T1xT2

-

0.3x45°

-

mm

indicates the position of pin 1

Table 24. Package outline.

5.4 Land Pattern

Figure 7

shows the land pattern. The land pattern is understood to be the open metal areas on the

PCB, onto which the DFN pads are soldered. The solder mask is understood to be the insulating

layer on top of the PCB covering the copper traces. It is recommended to design the solder pads

as a Non-Solder Mask Defined (NSMD) type. For NSMD pads, the solder mask opening should

provide a 60

μm to 75 μm design clearance between any copper pad and solder mask. As the pad

pitch is only 0.5 mm we recommend to have one solder mask opening for all 4 I/O pads on one

side. For solder paste printing it is recommended to use a laser-cut, stainless steel stencil with

electro-polished trapezoidal walls and with 0.1 or 0.125 mm stencil thickness. The length of the

stencil apertures for the I/O pads should be the same as the PCB pads. However, the position of

the stencil apertures should have an offset of 0.1 mm away from the center of the package. The

die pad aperture should cover about 70

– 90% of the die pad area –thus it should have a size of

about 0.9 mm x 1.6 mm. For information on the soldering process and further recommendation on

the assembly process please consult the Application Note HT_AN_SHTxx_Assembly_of_SMD_

Packages [1], which can be found on the Sensirion webpage.