XM014429B datasheet(30/83 Pages) XMOS

30 / 83 page

XU6--QF6B Datasheet

to achieve desired targets of heel, toe and side llets for solder-joints. The mechanical

drawings in Section

specify the dimensions and tolerances.

Ground and Thermal Vias

Vias under the heat slug into the ground plane of the PCB are recommended for a low

inductance ground connection and good thermal performance. Typical designs could

use 6 vias in a x grid, equally spaced across the ground paddle. In addition, you

should aim to have four VDD vias underneath each of the VDD paddles.

Moisture Sensitivity

XMOS devices are, like all semiconductor devices, susceptible to moisture absorption.

When removed from the sealed packaging, the devices slowly absorb moisture from the

surrounding environment. If the level of moisture present in the device is too high during

reow, damage can occur due to the increased internal vapour pressure of moisture.

Example damage can include bond wire damage, die lifting, internal or external package

cracks and/or delamination.

All XMOS devices are Moisture Sensitivity Level (MSL) - devices have a shelf life of

68 hours between removal from the packaging and reow, provided they are stored

below

C and 6% RH. If devices have exceeded these values or an included moisture

indicator card shows excessive levels of moisture, then the parts should be baked as

appropriate before use. This is based on information from Joint IPC/JEDEC Standard

For Moisture/Reow Sensitivity Classication For Nonhermetic Solid State Surface-Mount

Devices

J-STD-

Revision D.

.6 Reow

You should ensure that the board assembly process is optimised for the design; for de-

tails of the recommended reow prole, please refer to the Joint IPC/JEDEC standard

J-STD-.

XM014429B Datasheet(PDF) 30 Page - Xmos Ltd.