Microchip Technology AT49F040A-70JU

Overview

AT49F040A-70JU from Microchip Technology (formerly Atmel) is a 4 Mbit (512K × 8) 5V-only in-system reprogrammable Flash memory IC used for nonvolatile code and data storage in embedded microcontroller systems. It delivers 70 ns read access time, 20 µs/byte programming, 6-second sector erase, 10,000 write cycles, and features hardware data protection with boot block lockout for secure firmware storage in industrial control units.

For engineers reviewing the AT49F040A-70JU datasheet, AT49F040A-70JU pinout, AT49F040A-70JU application, or AT49F040A-70JU equivalent, key selection criteria include its 32-lead PLCC package, 5V-only operation without high-voltage programming, sector-based erase architecture (1×16KB boot + 2×8KB parameter + 8×64KB main blocks), CMOS standby current of 70 µA, and DATA polling/toggle bit for program/erase cycle detection.

Technical Context

The AT49F040A-70JU implements a command-driven Flash architecture with internal program control logic and timer, eliminating external high-voltage generators. Its sector architecture supports independent erasure of eight 64KB main memory blocks, two 8KB parameter blocks, and one 16KB boot block - the latter featuring programmable lockout to preserve secure boot code.

Operation relies on standard EPROM-like control signals (CE, OE, WE) and uses address/data multiplexing via I/O0–I/O7. Programming and erase are initiated by six-cycle software command sequences (e.g., 555H/AAH → AAH/55H → 80H → 555H/AAH → AAH/55H → 40H for boot lockout), with end-of-cycle detection via DATA polling on I/O7 or toggle bit behavior on I/O6.

Key Specifications

Pinout & Package

AT49F040A-70JU is supplied in a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package (JEDEC MS-016, Variation AE), measuring 12.4 mm × 12.4 mm × 3.4 mm, with gull-wing leads and pin 1 identifier notch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Flash memory applications.

Compared with MX29LV400CBTI-70G and EN29LV400AB-70TP, the AT49F040A-70JU provides native 5V-only operation in compact 32-lead PLCC with deterministic 16KB boot lockout - making it optimal for legacy 5V industrial controllers where board space and voltage simplicity are critical.

Availability

AT49F040A-70JU is available at Aetrix Electronics and suitable for industrial PLCs, automotive ECUs, medical diagnostics equipment, and networking switches requiring stable component supply across long product lifecycles.

Supply support for AT49F040A-70JU 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

Microchip Technology acquired Atmel in 2016 and maintains full support for legacy Atmel Flash memory products, including manufacturing, documentation, and technical assistance.

The AT49F040A-70JU belongs to Atmel's industrial-grade parallel Flash memory family, designed specifically for in-system reprogrammability in 5V embedded systems requiring secure, high-reliability nonvolatile storage with minimal external circuitry.

FAQ

What is the maximum operating temperature range for the AT49F040A-70JU?

The AT49F040A-70JU is rated for industrial operation from -40°C to +85°C. This range is validated per the device's DC and AC specifications, including 70 ns read timing, 20 µs byte programming, and 6-second sector erase performance under full temperature stress. The "I" suffix in ordering codes denotes industrial grade, and the "JU" package confirms Pb/halide-free PLCC construction compliant with this thermal specification.

Does the AT49F040A-70JU require external high-voltage programming circuitry?

No, the AT49F040A-70JU operates exclusively from a single 5V supply for both read and programming functions. Internal charge pumps generate necessary voltages for Flash cell manipulation. Programming is enabled only through precise six-cycle command sequences (e.g., 555H/AAH → AAH/55H → 80H) with VCC ≥ 3.8 V, eliminating external HV generators and simplifying system design compared to older EPROM or UV-erasable Flash devices.

How is boot block protection activated on the AT49F040A-70JU?

Boot block protection on the AT49F040A-70JU is activated by executing a specific six-cycle command sequence: load AAH to address 555H, 55H to address AAAH, 80H to address 555H, then AAH to 555H, 55H to AAAH, and finally 40H to 555H - with a 1-second pause before the last step. Once executed, the 16KB boot block (00000H–03FFFH) becomes permanently write-protected; status can be verified by reading I/O0 at address 00002H in software product ID mode.

What package type does the AT49F040A-70JU use, and what are its key mechanical dimensions?

The AT49F040A-70JU uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package, designated "32J" in Atmel's ordering nomenclature. Its body measures 12.4 mm × 12.4 mm with a maximum height of 3.4 mm. Lead pitch is 1.27 mm, and pin 1 is identified by a corner notch. This JEDEC MS-016-compliant package supports socketed prototyping and rework-friendly surface-mount assembly in industrial PCBs.

Can the AT49F040A-70JU be used as a direct replacement for EPROMs like the 27C040?

Yes, the AT49F040A-70JU is pin-compatible and functionally compatible with 27C040 EPROMs in 32-lead PLCC packages, sharing identical pinout (A0–A18, I/O0–I/O7, CE, OE, WE, VCC, GND). However, unlike EPROMs, it supports in-system reprogramming without UV erasure and requires command-based write/erase cycles - so host firmware must implement the AT49F040A-70JU's specific command protocol instead of simple write strobes.