The mechanical specifications for the packages show the dimensions in millimeters.

QFN40 5 x 5 mm package

Figure 1. QFN40 5 x 5 mm package

QFN40 dimensions in millimeters

Table 1. QFN40 dimensions in millimeters
A A1 A3 b D, E D2, E2 e K L
Min. 0.80 0.00 0.15 4.90 3.50 0.20 0.30
Nom. 0.85 0.035 0.203 0.20 5.00 3.60 0.40 0.35
Max. 0.90 0.05 0.25 5.10 3.70 0.40

WLCSP 2.531 x 2.531 mm package

Figure 2. WLCSP 2.531 x 2.531 mm package

WLCSP dimensions in millimeters

Table 2. WLCSP dimensions in millimeters
A A1 A3 b D E D2 E2 K L e
Min. 0.468 0.148 0.309 0.184
Nom. 0.491 0.327 2.531 2.531 2.100 2.100 1.025 1.075 0.350
Max. 0.514 0.180 0.345 0.244