Winbond W25Q has been the default serial NOR Flash for many embedded designs. When lead times or pricing move, teams look for a qualified second source. BOYA BY25Q and BY25FQ devices are a common alternative in the same class. This guide explains what to verify when migrating from W25Q to BOYA, and which BOYA parts we stock that sit in the same density and package brackets.
1. Why migrate to a BOYA alternative?
A qualified second source reduces supply-chain risk. BOYA offers a wide density range and standard packages that match the footprints commonly used by W25Q devices. The goal is not to change the design philosophy — it is to have two sources that both pass the same bench tests.
2. Cross-reference density map
| Part Number | Description | Link |
|---|---|---|
| BY25Q20AWUIG(R) | 2 Mbit — W25Q20 class | BY25Q20AWUIG(R) |
| BY25Q40AWTIG | 4 Mbit — W25Q40 class | BY25Q40AWTIG |
| BY25Q80AWUIG | 8 Mbit — W25Q80 class (USON-8) | BY25Q80AWUIG |
| BY25Q16ESTIG | 16 Mbit — W25Q16 class | BY25Q16ESTIG |
| BY25Q64ESTIG(R) | 64 Mbit — W25Q64 class | BY25Q64ESTIG(R) |
| BY25Q128ASSIG | 128 Mbit — W25Q128 class | BY25Q128ASSIG |
| BY25FQ256FSSIG | 256 Mbit — W25Q256 class | BY25FQ256FSSIG |
3. Migration checklist
- Supply voltage. Confirm 3.3 V vs 1.8 V operation matches your host.
- SPI mode and clock. Check standard/dual/quad SPI support and maximum clock frequency.
- Device ID. Update detection code if your bootloader reads the JEDEC ID.
- Status register. Block-protection bits and write-enable defaults can differ.
- Erase sector size and timing. Adjust timeouts and erase granularity in your Flash driver.
- Power-up / power-down sequence. Verify the part returns to a known state on reset.
4. Validate on the bench
Run your production bootloader and application firmware on the BOYA part at the corners of temperature and voltage. Do not rely on datasheet similarity alone. We can supply samples of BY25Q16ESTIG, BY25Q64ESTIG(R) and BY25Q128ASSIG for qualification.
Frequently asked questions
Can I replace a Winbond W25Q with a BOYA BY25Q?
BOYA BY25Q and BY25FQ parts are often evaluated as functional alternatives to Winbond W25Q serial NOR Flash. Many parts share similar packages, pinouts and command structures, but you must verify voltage, timing, JEDEC ID and protection registers before committing to a swap.
What must I check before substituting NOR Flash?
Check supply voltage, SPI mode, clock frequency, command set, device ID, status-register layout, block-protection defaults, erase sector sizes and timing. Differences in any of these can stop firmware from booting or cause field failures.
Do I need to change my firmware?
Often no, if the command set and status register match. If the device ID is used for detection, you will need to add the BOYA ID. If block protection is different, update your Flash driver accordingly.
Which BOYA densities match common W25Q parts?
Common mappings include 2 Mbit, 4 Mbit, 8 Mbit, 16 Mbit, 32 Mbit, 64 Mbit, 128 Mbit and 256 Mbit. We stock several of these densities in BOYA; send us the exact W25Q part for a cross-reference.
About us & trademarks: JTDZ Tech (Shenzhen Jingteng Electronics Technology Co., Ltd.) is an independent distributor of electronic components. We are not an authorised distributor or representative of the manufacturers named in this article. Manufacturer and part names are used for indicative purposes only, to help identify the components discussed; all trademarks remain the property of their respective owners. Always verify specifications against the official datasheet before design-in or purchase.
Recommended next steps
If you are sourcing any of the parts mentioned in this guide, we can help you confirm stock, pricing, and lead times quickly.
- Upload your BOM — send your full parts list and receive a consolidated quote within 2 business hours.
- Browse related in-stock lines: Memory / Logic Devices.
- Contact our team for hard-to-find or end-of-life components.
