Asahi Kasei Microdevices/AKM AK6440BL

Overview

AK6440BL from Asahi Kasei Microdevices is a 4096-bit (256 × 16) serial CMOS EEPROM with 1.8V–5.5V supply operation, 1 MHz max clock frequency at VCC = 2.5V, and 100K write endurance. It interfaces directly with one-chip microcomputer serial ports using a 3-line negative-clock synchronous interface (CS/SK/DI/DO), and features hardware/software write protection and Ready/Busy status output via DO pin. Used for low-density non-volatile data storage in space-constrained industrial and embedded systems.

For engineers reviewing the AK6440BL datasheet, AK6440BL pinout, AK6440BL application, or AK6440BL equivalent, key selection considerations include its 8-pin SON package, ultra-low standby current (0.8 µA), automatic write timeout with auto-erase, and RESET-controlled write execution safety - all critical for battery-powered and fail-safe data logging designs.

Technical Context

The AK6440BL implements a 3-wire serial interface with CS-active-low selection, SK-synchronous data transfer (rising edge for DI, falling edge for DO), and integrated high-voltage charge pump for internal write voltage generation. Its instruction set includes READ, WRITE, WREN, and WRDS, each structured as 8-bit op-code + 8-bit address + 16-bit data (or don't-care fields).

It supports automatic address increment during sequential reads, Ready/Busy status reporting on DO while CS is low and SK is low, and dual write protection: software-enabled via WREN/WRDS commands and hardware-enforced by RESET pin level (WRITE only executes when RESET = low). The device enters high-impedance DO state except during data output or status reporting.

Key Specifications

Pinout & Package

AK6440BL uses an 8-pin Plastic SON (Small Outline No-lead) package with exposed thermal pad, optimized for high-density PCB layouts and automated assembly. Pin 1 is marked by a dot; NC pins must remain open.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial EEPROM applications.

Compared with AK6440BL, the 25LC040A offers faster throughput but sacrifices hardware write gating and status visibility, while the CAT24C04HU4I-GT3 integrates into existing I²C ecosystems but increases firmware complexity and removes real-time BUSY monitoring - making AK6440BL optimal for resource-constrained, safety-aware embedded controllers.

Availability

AK6440BL is available at Aetrix Electronics and suitable for industrial sensor calibration, consumer device configuration, medical diagnostic logging, and automotive body control module settings requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for AK6440BL includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Asahi Kasei Microdevices Corporation (AKM) is a Japanese semiconductor company specializing in analog, mixed-signal, and sensor ICs, with core expertise in audio, magnetic sensing, and non-volatile memory technologies.

The AK6440B series was designed specifically for low-density, high-reliability serial data storage in space- and power-constrained embedded systems - emphasizing robustness, wide-VCC compatibility, and simplified microcontroller integration without external support components.

FAQ

What is the maximum clock frequency supported by AK6440BL?

The AK6440BL supports up to 1 MHz maximum clock frequency when VCC is 2.5V or higher. At lower supply voltages (1.8V ≤ VCC < 2.5V), the maximum clock period is 1.5 µs (≈667 kHz). This frequency scaling ensures reliable timing margins across its full 1.8–5.5V operating range, and the AK6440BL datasheet specifies tSKP2 = 1.5 µs under those conditions.

Does AK6440BL require an external high-voltage supply for write operations?

No, the AK6440BL does not require an external high-voltage supply. It integrates an on-chip charge pump that generates the necessary programming voltage internally from the standard VCC supply (1.8–5.5V). This eliminates the need for external VPP circuitry, simplifying design and reducing bill-of-materials cost - a key feature confirmed in the AK6440BL functional description and block diagram.

How does the RESET pin affect write operations in AK6440BL?

The RESET pin acts as a hardware gate for WRITE instructions in the AK6440BL: the device ignores any WRITE command unless RESET is held low during both instruction input and the subsequent 10 ms automatic write timeout period. If RESET goes high mid-write, programming halts and the target word becomes invalid - this behavior is explicitly defined in the AK6440BL pin description and functional timing diagrams.

Can AK6440BL operate reliably at 1.8V supply voltage?

Yes, the AK6440BL is fully specified for operation down to 1.8V, including read, write, and standby modes. Electrical characteristics tables confirm ICC6 = 0.15 mA (read) and ICCS = 0.8 µA (standby) at VCC = 1.8V, and AC timing parameters (tSKP2, tSKW2) are explicitly defined for this voltage range - ensuring compatibility with modern ultra-low-voltage microcontrollers.

What package type is used for AK6440BL, and how does it differ from AK6440BH?

The AK6440BL uses an 8-pin Plastic SON (Small Outline No-lead) package with an exposed thermal pad, whereas the AK6440BH uses an 8-pin MSOP package. Both share identical pin functions and electrical specifications, but the SON variant offers smaller footprint (3.0 × 3.0 mm vs. 4.9 × 6.0 mm MSOP) and improved thermal performance - a distinction clearly documented in the AK6440B product table on page 3 of the DAS03E-01 datasheet.