IP4856CX25_C

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© 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

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

The device can withstand at least three reflows with this profile.

Fig 10. Pb-free solder reflow profile