IP4856CX25_C All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 2 — 15 October 2014 16 of 21
NXP Semiconductors
IP4856CX25/C
SD 3.0-compliant memory card integrated dual voltage level translator
15. Design and assembly recommendations
15.1 PCB design guidelines
For optimum performance, use a Non-Solder Mask PCB Design (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. For this case, refer to Table 15
for the recommended PCB design parameters.
15.2 PCB assembly guidelines for Pb-free soldering
Table 15. Recommended PCB design parameters
Parameter Value or specification
PCB pad diameter 250 m
Micro-via diameter 100 m (0.004 inch)
Solder mask aperture diameter 325 m
Copper thickness 20 m to 40 m
Copper finish AuNi or OSP
PCB material FR4
Table 16. Assembly recommendations
Parameter Value or specification
Solder screen aperture diameter 290 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 10
The device can withstand at least three reflows with this profile.
Fig 10. Pb-free solder reflow profile
DDL
7
UHIORZSHDN
7
&
FRROLQJUDWH
SUHKHDW
W
W
W
W
W
WV
