IP4085_4385_4386_4387_CX4_1

© NXP B.V. 2009. All rights reserved.

Product data sheet

Rev. 01 — 26 March 2009

13 of 16

NXP Semiconductors

IP4085/4385/4386/4387/CX4

Integrated high-performance ESD-protection diodes

11. Design and assembly recommendations

11.1 PCB design guidelines

For optimum performance it is recommended to 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 6 for the recommended PCB design parameters.

11.2 PCB assembly guidelines for Pb-free soldering

Table 6.

Recommended PCB design parameters

Parameter

Value or Specification

PCB pad diameter

200

µm

Micro-via diameter

100

µm (0.004 inch)

Solder mask aperture diameter

370

µm

Copper thickness

20

µm to 40 µm

Copper finish

AuNi

PCB material

FR4

Table 7.

Assembly recommendations

Parameter

Value or Specification

Solder screen aperture diameter

330

µm

Solder screen thickness

100

µm (0.004 inch)

Solder paste: Pb-free

SnAg (3 % to 4 %) Cu (0.5 % to 0.9 %)

Solder/flux ratio

50/50

Solder reflow profile

see Figure 22

The device is capable of withstanding at least three reflows of this profile.

Fig 22. Pb-free solder reflow profile

001aai943

250

230

217

T

(

°C)

cooling rate

pre-heat

t (s)