microSD Storage for Single-Board Computers and Dev Kits
A single-board computer boots and runs its operating system from the microSD card, so the card is not storage you add later — it is part of the board’s boot path. What matters is reliable enumeration on the host, consistent random read and write for an OS workload, and a supply plan that lasts as long as the board is sold. WINTEL supplies microSD-class TF cards from 4GB to 256GB with read and write speed specified per project, including Application Performance Class A1 or A2 where the board runs apps from the card. For makers and OEMs shipping their own enclosure, we also supply semi-finished boards and UDP modules. Send your host interface, OS image size and capacity requirement for a specification you can design against.
What this buyer actually cares about
The card is on the boot path
An SBC that will not boot from a particular card is a support ticket, not a spec-line issue. Enumeration reliability depends on the controller solution far more than on the capacity.
Random read/write, not just sequential
An OS workload scatters small reads and writes across the card. Application Performance Class (A1 or A2) describes that mixed workload, which a video speed class does not capture.
Capacity against the OS image
A board image plus user storage can need far more than a bare OS. Sizing the card to the image plus headroom avoids shipping a board that fills up on first boot.
Long-term availability
NAND suppliers discontinue packages on their own schedule. A board with a multi-year life needs a supply plan, not just a current price.
Mechanical fit inside the enclosure
On a maker board the slot is exposed; in a productised enclosure the card may be inaccessible once closed, which changes the service conversation.
What we do about it
- Supply microSD-class TF cards from 4GB to 256GB for boot and storage
- Specify A1 or A2 Application Performance Class where the board runs apps from the card
- Select the controller solution against your host requirements
- Supply semi-finished boards and UDP modules for your own enclosure
- Provide the specification and drawing for your design review
- Discuss long-term supply planning for boards with a multi-year life
Recommended configuration
A starting point drawn from the workloads buyers in this scenario describe. We confirm the exact specification against your bitrate, host and target date rather than quoting a generic figure.
| Dimension | Recommended starting point |
|---|---|
| Capacity | 16–64 GB (OS image + user storage) |
| Speed | Application Performance Class A1 / A2 for app workloads |
| Flash grade | A+ grade, controller matched to host |
Common procurement risks
What buyers in this scenario most often get wrong — and how we address it.
- A card that will not boot on your specific board (controller issue)
- Random read/write under-rated for an OS workload
- Capacity sized to a round number, not the image
- NAND package discontinued during the board’s life
Buyer checklist
- Confirm your workload (bitrate, retention window, duty cycle) before specifying capacity
- Match the speed class to the actual workload, not a marketing number
- Ask for the silicon source and grade in writing before you commit
- Request a physical sample and approve it before bulk production
- Confirm MOQ, lead time and Incoterms in the written quotation
Products for this application
Tell us your workload, target capacity and the date you need material — and, if you have it, your bitrate or retention requirement. We will come back with a specification and a schedule rather than a generic price list.
Send your requirementFrequently asked questions
Does an SBC need an A1 or A2 card?
If the board runs applications from the card rather than just booting, A2 (4,000 read / 2,000 write IOPS) performs better than A1 (1,500 / 500 IOPS). The SD Association defines both as an Application Performance Class. Tell us how the board uses the card and we will specify the right class.
Why does my board boot from one card but not another?
It is almost always the controller solution, not the capacity. The host enumerates the card through its controller, and some controller and host combinations simply do not initialise reliably. Send your host and we will propose a matched solution before you commit a layout.
What capacity should I ship with the board?
Size it from your OS image plus the user storage you expect, not from a round number. A 32GB card is usually enough for a lightweight Linux image; a heavier desktop image wants 64GB or more. Confirm the image size first.
Can you supply a drawing and specification?
Yes. Send your integration requirements — host interface, capacity, speed class and mechanical clearance — and we will provide the specification and drawing for design review.
What happens if the NAND package we use gets discontinued?
It is a real risk across the industry. Tell us your expected production life at enquiry stage and we will discuss how to plan for it, including whether a semi-finished board gives you more control.