BY25Q128ASSIG(T)

Memory IC Overview

The BY25Q128ASSIG(T) is a 128M-bit Serial Peripheral Interface (SPI) NOR Flash memory manufactured by BYTe Semiconductor. It supports Standard, Dual, and Quad SPI modes with clock rates up to 108MHz for Fast Read. The device operates on a single supply voltage ranging from 2.7V to 3.6V and features a flexible architecture with 4KB sectors and 32/64KB blocks. It includes software and hardware write protection mechanisms, three 256-byte security registers with OTP locks, and supports program/erase suspend and resume functions.

Memory IC Feature Summary

• Supports Standard, Dual, and Quad SPI interfaces with data transfer speeds up to 432Mbits/s in Quad I/O mode.
• Features comprehensive write protection including Block Protect bits, Hardware Write Protect (/WP), and Software Reset capabilities.
• Includes three 256-byte Security Registers with One-Time Programmable (OTP) Lock bits for permanent protection.
• Supports Program and Erase Suspend/Resume operations to allow non-intrusive read access during background writes.

Memory IC Applications

• Firmware storage for microcontrollers and system-on-chip devices
• Code execution in place (XIP) applications
• Data logging and parameter storage in industrial control systems
• Configuration storage for network equipment

Memory IC Procurement Notes

Verify the specific package suffix 'SIG' corresponds to the required 8-pin SOP or WSON form factor as defined in the manufacturer's ordering information. Confirm that the temperature grade matches the application requirements, as the datasheet lists Commercial, Industrial (-40°C to +85°C), and Extended Industrial (-40°C to +105°C) options within the BY25Q128AS family. Ensure the source document explicitly links the 'SIG' suffix to the physical package dimensions and pinout configuration before finalizing procurement.

Memory IC Selection Notes

Select this component when a 128M-bit density is required with high-speed Quad SPI interface capabilities. It is suitable for designs needing robust data integrity features such as hardware write protection and secure boot support via OTP security registers. Consider the operating voltage range of 2.7V to 3.6V and ensure the host system provides stable power decoupling. Verify that the available package types (SOP or WSON) fit the PCB layout constraints.

Memory IC Part Context

The BY25Q128AS belongs to BYTe Semiconductor's 128M-bit SPI NOR Flash family. It is designed as a drop-in replacement for similar density devices from other manufacturers, offering comparable pinouts and command sets. The product line emphasizes low power consumption and high endurance, targeting cost-sensitive consumer electronics and industrial applications requiring reliable non-volatile storage.

Memory IC Replacement Considerations

Publicly confirmed substitute part numbers include GD25Q128ESIG, MX25U12832FM2I02, and W25Q128JVSIQ. These alternatives share similar 128M-bit densities and SPI interfaces but may differ in package styles, maximum clock frequencies, or specific protection features. Always verify electrical characteristics and pin compatibility against the target design specifications.

Memory IC FAQ

How does the Quad Enable (QE) bit affect the /WP and /HOLD pins?

When the QE bit is set to 1, the /WP and /HOLD pins are disabled as control signals and function as dedicated bidirectional I/O pins (IO2 and IO3) for Quad SPI data transfer. In this mode, hardware write protection via the /WP pin is not available.

What is the function of the LB (Lock Bit) in the Status Register?

The LB bits (LB3, LB2, LB1) are One-Time Programmable (OTP) bits that provide permanent write protection for the Security Registers. Once set to 1, these bits cannot be cleared, ensuring the security settings remain locked indefinitely.

Can the BY25Q128ASSIG(T) operate in both SPI Mode 0 and Mode 3?

Yes, the device supports both SPI Bus Mode 0 and Mode 3. Data is latched on the rising edge of the serial clock and shifted out on the falling edge, compatible with standard SPI timing requirements.