Description of the JMS901 Metal Shield

1. Material: It is typically constructed from a stamped, durable aluminum alloy or thin stainless steel, designed to be rigid yet lightweight.
2. Size: Generally matches the footprint of the UFS BGA package on the board, often around 

Key Features and Functions

1. Protects the UFS and JMS901 chips from external electromagnetic noise and prevents the high-speed data lines from radiating interference, which is critical for USB 3.1 speeds.
2. Heat Dissipation: Acts as a heat spreader, helping to transfer heat away from the UFS chip and the JMS901 controller during high-speed data transfer (

1. ), preventing thermal throttling.
2. Physical Protection: Provides a protective barrier for the soldered chips against mechanical stress and environmental elements.

Why the Metal Shield is Needed for JMS901 Boards

1. High-Speed Signal Integrity: The JMicron JMS901 is a USB 3.1 Gen1 to UFS 2.1/2.2 bridge controller. At these speeds, electromagnetic noise can degrade data signal quality, causing file transfer errors or disconnects. The shield stabilizes signal integrity.
2. Heat Management: UFS storage can get very hot, especially when used inside a small pendrive housing without active cooling. The shield keeps the components within operational temperature ranges.
3. Stability: The shield helps ensure a consistent, reliable connection between the high-performance UFS flash chip and the USB host.