Datasheet
IP4085_4385_4386_4387_CX4 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.
Product data sheet Rev. 2 — 14 December 2012 12 of 18
NXP Semiconductors
IP4085/4385/4386/4387/CX4
Integrated high-performance ESD protection diodes
9. Design and assembly recommendations
9.1 PCB design guidelines
For optimum performance, use a Non-Solder Mask Defined (NSMD), also known as a
copper-defined design, incorporating laser-drilled micro-vias connecting the ground pads
to a buried ground-plane layer. This results in the lowest possible ground inductance and
provides the best high frequency and ESD performance. Refer to Table 8
for the
recommended PCB design parameters.
9.2 PCB assembly guidelines for Pb-free soldering
Table 7. Package outline dimensions of IP438xCX4 (WLCSP4)
Symbol Min Typ Max Unit
A 0.560.610.66mm
A
1
0.18 0.20 0.22 mm
A
2
0.38 0.41 0.44 mm
b 0.210.260.31mm
D 0.710.760.76mm
E 0.710.760.81mm
e0.40.40.4mm
Table 8. Recommended PCB design parameters
Parameter Value or Specification
PCB pad diameter 200 m
Micro-via diameter 100 m (0.004 inch)
Solder mask aperture diameter 370 m
Copper thickness 20 m to 40 m
Copper finish AuNi
PCB material FR4
Table 9. Assembly recommendations
Parameter Value or Specification
Solder screen aperture diameter 330 m
Solder screen thickness 100 m (0.004 inch)
Solder paste: Pb-free SnAg (3 % to 4 %) Cu (0.5 % to 0.9 %)
Solder to flux ratio 50 : 50
Solder reflow profile see Figure 18