Microchip Technology AT49F040A-55PI

Overview

AT49F040A-55PI from Atmel is a 4-Mbit (512K × 8) single-voltage 5V-only Flash memory IC with 55 ns read access time, sector-based architecture (1×16K boot block + 2×8K parameter blocks + 8×64K/32K main blocks), and hardware data protection. It supports byte-by-byte programming (20 µs/byte typical), chip/sector erase (6 s max), and DATA polling for end-of-program detection - used in embedded firmware storage, BIOS code retention, and industrial controller boot memory.

For engineers reviewing the AT49F040A-55PI datasheet, AT49F040A-55PI pinout, AT49F040A-55PI application, or AT49F040A-55PI equivalent, key selection considerations include 5V-only operation, PLCC-32 packaging, boot-block lockout capability, 10,000 write cycles endurance, and compatibility with standard EPROM-like bus interface timing.

Technical Context

The AT49F040A-55PI implements a CMOS-based Flash memory architecture with internal program control logic, automatic erase timing, and dual-line CE/OE enable for bus contention avoidance. Its sector organization enables selective erasure of boot, parameter, or main memory blocks without affecting others.

It uses standard microprocessor write timings for command entry, latches addresses on the falling edge of CE or WE, and data on the rising edge. Hardware protections include VCC sense (<3.8V inhibits programming), noise filtering (<15 ns pulses ignored), and input state locking (OE low / CE high / WE high disables writes).

Key Specifications

Pinout & Package

AT49F040A-55PI is supplied in a 32-lead Plastic Leaded Chip Carrier (PLCC-32) package per JEDEC MS-016, Variation AE, with pin 1 identifier at corner and J-leads for surface-mount compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AM29LV040B-55EC and SST39VF400A-55-4C-NHE, the AT49F040A-55PI uniquely delivers true 5V-only operation with hardware-enforced boot-block protection and PLCC-32 packaging - making it optimal for legacy industrial and computing platforms where voltage simplicity and firmware security are primary constraints.

Availability

AT49F040A-55PI is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy PC BIOS retention, and embedded system bootloader applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for AT49F040A-55PI 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

Atmel Corporation (now part of Microchip Technology) is a semiconductor manufacturer specializing in microcontrollers, Flash memory, and secure authentication ICs, with a legacy of robust nonvolatile memory solutions for industrial and computing markets.

The AT49F040A product line was designed for in-system reprogrammable firmware storage in 5V embedded systems, emphasizing reliability, sector-level flexibility, and hardware data integrity - targeting BIOS, bootloader, and industrial control applications.

FAQ

What is the operating temperature range for the AT49F040A-55PI?

The AT49F040A-55PI is rated for industrial operation from –40°C to +85°C. This range is validated per its DC and AC specifications, including 55 ns access time, 20 mA active current, and 70 µA standby current, making it suitable for deployment in factory automation, networking equipment, and outdoor embedded systems where thermal stability is critical. The AT49F040A-55PI maintains full functionality across this range without derating.

Does the AT49F040A-55PI require a high-voltage programming signal?

No, the AT49F040A-55PI operates exclusively at 5.0 V ±10% for both read and programming functions - no external VPP or high-voltage generator is needed. Programming is initiated via standard 5V command sequences applied to CE, WE, and address/data lines. This eliminates charge pump circuitry and simplifies board design compared to older Flash devices requiring 12 V. The AT49F040A-55PI's VCC sense feature further ensures programming is inhibited below ~3.8 V.

How is boot block protection enabled on the AT49F040A-55PI?

Boot block protection on the AT49F040A-55PI is enabled by executing a six-cycle command sequence: load 0xAA to address 0x555, 0x55 to 0xAAA, 0x80 to 0x555, then 0xAA/0x55/0x40 to 0x555. Once activated, the 16K-byte boot sector (00000H–03FFFH) becomes permanently write- and erase-protected. The AT49F040A-55PI supports software lockout detection by reading I/O0 at address 00002H in product ID mode - high = locked, low = unlocked.

What package type does the AT49F040A-55PI use, and is it lead-free?

The AT49F040A-55PI uses a 32-lead Plastic Leaded Chip Carrier (PLCC-32) package per JEDEC MS-016, Variation AE, with dimensions 12.5 mm × 15.0 mm × 3.5 mm. Per Atmel's documentation and RoHS compliance statements, the AT49F040A-55PI is lead-free and halogen-free, meeting EU Directive 2011/65/EU. The PLCC-32 form factor provides robust mechanical mounting and thermal performance for through-hole or surface-mount assembly.

Can the AT49F040A-55PI be used as a direct replacement for standard EPROMs like the 27C040?

Yes, the AT49F040A-55PI is functionally and pin-compatible with 27C040 EPROMs in read mode: identical 32-pin PLCC footprint, same CE/OE/WE control signals, and matching 55 ns access timing. However, programming requires command sequences instead of UV erasure, and the AT49F040A-55PI supports in-system reprogramming without socket removal. Host firmware must implement Flash-specific erase/write protocols, but bus interface logic remains unchanged.