User Manual
Table Of Contents
- Introduction
- Features
- Table of Contents
- 1. Ordering Information and Module Marking
- 2. Block Diagram
- 3. Pinout and Package Information
- 4. Electrical Characteristics
- 5. Power Management
- 6. Clocking
- 7. CPU and Memory Subsystem
- 8. WLAN Subsystem
- 9. Bluetooth Low Energy 4.0
- 10. External Interfaces
- 11. Application Reference Design
- 12. Module Outline Drawings
- 13. Design Consideration
- 14. Reflow Profile Information
- 15. Module Assembly Considerations
- 16. Regulatory Approval
- 17. Reference Documentation
- 18. Document Revision History
- The Microchip Web Site
- Customer Change Notification Service
- Customer Support
- Product Identification System
- Microchip Devices Code Protection Feature
- Legal Notice
- Trademarks
- Quality Management System Certified by DNV
- Worldwide Sales and Service
14. Reflow Profile Information
This section provides the guidelines for the reflow process to get the module soldered to the customer's
design.
14.1 Storage Condition
14.1.1 Moisture Barrier Bag Before Opening
A moisture barrier bag must be stored at a temperature of less than 30°C with humidity under 85% RH.
The calculated shelf life for the dry-packed product is 12 months from the date the bag is sealed.
14.1.2 Moisture Barrier Bag Open
Humidity indicator cards must be blue, < 30%.
14.2 Solder Paste
The SnAgCu eutectic solder with melting temperature of 217°C is most commonly used for lead-free
solder reflow application. This alloy is widely accepted in the semiconductor industry due to its low cost,
relatively low melting temperature, and good thermal fatigue resistance. Some recommended pastes
include NC-SMQ
®
230 flux and Indalloy
®
241 solder paste made up of 95.5 Sn/3.8 Ag/0.7 Cu or SENJU
N705-GRN3360-K2-V Type 3, no clean paste.
14.3 Stencil Design
The recommended stencil is laser-cut, stainless-steel type with thickness of 100 µm to 130 µm and
approximately a 1:1 ratio of stencil opening to pad dimension. To improve paste release, a positive taper
with bottom opening 25 µm larger than the top is utilized. Local manufacturing experience may find other
combinations of stencil thickness and aperture size to get good results.
14.4 Baking Conditions
This module is rated at MSL level 3. After the sealed bag is opened, no baking is required within 168
hours as long as the devices are held at ≤ 30°C/60% RH or stored at < 10% RH.
The module requires baking before mounting if:
• The sealed bag has been open for more than 168 hours
• The humidity indicator card reads more than 10%
• SIPs need to be baked for eight hours at 125°C
14.5 Soldering and Reflow Condition
Optimization of the reflow process is the most critical factor considered for lead-free soldering. The
development of an optimal profile must account the paste characteristics, the size of the board, the
density of the components, the mix of the larger and smaller components, and the peak temperature
requirements of the components. An optimized reflow process is the key to ensuring a successful lead-
free assembly and achieves high yield and long-term solder joint reliability.
ATWINC3400-MR210CA
© 2017 Microchip Technology Inc.
Draft Datasheet Preliminary
DS00000000A-page 41