UPMU-M3L1X-B-EK Silicon Labs, UPMU-M3L1X-B-EK Datasheet - Page 91

• Manufacturer Part Number: UPMU-M3L1X-B-EK
• Description: Daughter Cards & OEM Boards UDP SiM3L1xx MCU Card (no LCD)
• Manufacturer: Silicon Labs

Specifications of UPMU-M3L1X-B-EK

• Product: MCU Cards
• Core: ARM Cortex M3
• Data Bus Width: 32 bit
• Description/function: MCU Card (No LCD) to use with UDP Motherboard
• Interface Type: I2C, SPI, UART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Tool Is For Evaluation Of: SiM3L1xx
• For Use With: SiM3L1xx

6.8.1. QFN-40 Solder Mask Design
All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad
is to be 60 µm minimum, all the way around the pad.
6.8.2. QFN-40 Stencil Design
6.8.3. QFN-40 Card Assembly
1. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure
2. The stencil thickness should be 0.125 mm (5 mils).
3. The ratio of stencil aperture to land pad size should be 1:1 for all pads.
4. A 3x3 array of 1.1 mm square openings on a 1.6 mm pitch should be used for the center ground pad.
1. A No-Clean, Type-3 solder paste is recommended.
2. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body
good solder paste release.
Components.
Rev 0.5
SiM3L1xx
91