Navman jupiter la000605d User Manual

LA000605D © 2007 Navman New Zealand. All rights reserved. Proprietary information and specifications subject to change without notice.

The Jupiter 32 uses the latest Land Grid Array (LGA) technology. Solder interconnect is 

formed solely by solder paste applied to the board assembly. This results in a low stand-off 

height, depending on solder paste volume and Printed Circuit Board (PCB) geometry. This 

makes LGA ideal for small form-factor applications. Solder joint reliability studies indicate that 

LGA greatly exceed typical industry reliability. 

The Jupiter 32 has 34 surface mount connection pads that have a base metal of copper 

with an Electroless Nickel Immersion Gold (ENIG) finish. This is suitable for a lead free 

manufacturing process. Critical factors to ensure successful circuit board assembly with LGA 

devices include, the design of the solder paste stencil, the solder paste and reflow profile 

used. Stencil attributes that have been shown to succeed in tests are solder stencil thickness, 

aperture diameter, paste release characteristics, and practices to ensure consistent solder 

paste volumes that exceed recommended minimums.

4.1.1 Solder paste type
The module will accept all commonly used solder pastes. The solder paste can be lead 

based or lead-free. In all processes, factors such as circuit board thickness, fabrication 

complexity, assembly process compatibility, and surface finish should be taken into 

consideration. Also, due to the low standoff height of LGA devices and difficulty cleaning, a 

no-clean paste is recommended. 

4.1.2 Solder paste mask size
Solder paste mask size should be adjusted by experimentation according to the production 

process requirements. As a starting point, a 0.75:1 (paste mask:pad size) ratio is 

recommended.

4.1.3 Solder paste stencils
A 0.125 mm (5 mil) thick stencil is recommended with LGA. 

4.1.4 Reflow profile recommendations
An optimal reflow profile depends on solder paste properties and should be optimised and 

proven out as part of an overall process development. The following guidelines represent 

good soldering practices to help yield high quality assemblies with minimum rework.
It is important to provide a solder reflow profile that matches the solder paste supplier’s 

recommendations. Some fluxes need a long dwell time below the temperature of 180°C, 

while others will be burned up in a long dwell. Temperatures out of bounds of the solder paste 

flux recommendation could result in poor solderability of components on the board. Solder 

paste suppliers can recommend an suitable reflow profile to give the best solderability. The 

maximum reflow temperature is 260 °C for 10 seconds. 
The typical reflow profile consists of four sections. In the preheat section, the PCB assembly 

should be preheated at the maximum rate of 1° to 2° C/sec to start the solvent evaporation 

and to avoid thermal shock. The assembly can then be heated for 60 to 120 seconds to 

remove solder volatiles and activate the flux so the temperature of the package rises above 

100° C. The reflow section of the profile, the time above liquidus (approx. 185° C), can be 

between 45 to 60 seconds with a peak temperature in the range of 230° to 260° C. This 

allows all solder joints on the assembly to fully reflow and a maximum peak temperature that 

is below the maximum that the devices or solder material can tolerate. Finally, the assembly 

can undergo cool-down in the fourth section of the liquidus point (approx. 185° C). The actual 

profile parameters depends upon the recommendations of the solder paste supplier and 

other reflow requirements of the customer’s PCB.
Refer to Figure 4-1 for sample lead and lead-free reflow profiles.