IP4338CX24LF_2

© NXP B.V. 2009. All rights reserved.

Product data sheet

Rev. 02 — 20 August 2009

8 of 12

NXP Semiconductors

IP4338CX24/LF

10-channel integrated filter network with ESD input protection

9.

Soldering of WLCSP packages

9.1 Introduction to soldering WLCSP packages

This text provides a very brief insight into a complex technology. A more in-depth account

of soldering WLCSP (Wafer Level Chip-Size Packages) can be found in application note

AN10439 “Wafer Level Chip Scale Package” and in application note AN10365 “Surface

mount reflow soldering description”.

Wave soldering is not suitable for this package.

All NXP WLCSP packages are lead-free.

9.2 Board mounting

Board mounting of a WLCSP requires several steps:

1. Solder paste printing on the PCB

2. Component placement with a pick and place machine

3. The reflow soldering itself

9.3 Reflow soldering

Key characteristics in reflow soldering are:

reducing the process window

window for a mix of large and small components on one board

heated to the peak temperature), and cooling down. It is imperative that the peak

temperature is high enough for the solder to make reliable solder joints (a solder paste

characteristic) while being low enough that the packages and/or boards are not

damaged. The peak temperature of the package depends on package thickness and

Moisture sensitivity precautions, as indicated on the packing, must be respected at all

times.

Studies have shown that small packages reach higher temperatures during reflow

Table 6.

Lead-free process (from J-STD-020C)

Package thickness (mm)

Package reflow temperature (

°C)

< 350

350 to 2000

> 2000

< 1.6

260

260

260

1.6 to 2.5

260

250

245

> 2.5

250

245

245