McDry Ultra-Low Humidity Storage Cabinets: Handling and Storage within McDry

Storing in 5 % RH and 10 % RH storage cabinets in accordance with IPC/JEDEC J-STD 033D

In accordance with IPC/JEDEC J-STD-033D, IC packages that have been removed from MBBs must be kept under a condition 5% or 10% relative humidity to prevent components from absorbing moisture. However, during the mounting process, opening and closing of dry cabinet storage doors may occur frequently in order to remove and replace moisture-sensitive devices. This will allow ambient air to flow into the cabinet and may raise the RH level. To limit this from occurring and to keep the relative humidity inside of the cabinet below 5% or 10% as specified, a consistent, ultra-low humidity storage level is recommended. Therefore, the storage guidelines utilizing the McDry cabinet corresponding to the repetition of opening and closing of doors are as follows

Model RH level Frequency of opening and closing of doors Usage example
DXU models 1% RH Once in approx.
10 – 20mins.
  1. Ultra-low humidity storage of ICs for cabinets that are accessed frequently.
  2. Storage of IC packages that require ultra-low humidity storage such as components with high MSL classifications.
MC
MCU models
1% RH Once in approx.
0.5hr – 2hrs.
  1. Ultra-low humidity storage of ICs for cabinets that are not accessed frequently.
  2. Long-term storage of IC packages and electrical components.
  3. Storage of PCBs, etc.