Microchip Technology AT29LV040A-15JC

Overview

AT29LV040A-15JC from Atmel is a 4-Mbit (512K × 8) 3.3V-only Flash memory IC organized in 2048 sectors of 256 bytes each, featuring 150 ns read access time, software-controlled sector erase/program, and dual 16K-byte boot blocks with independent lockout. It operates across commercial temperature range (0°C to 70°C), supports CMOS/TTL-compatible I/O, and enables in-system reprogramming without high-voltage inputs - used in embedded firmware storage and boot code retention.

For engineers reviewing the AT29LV040A-15JC datasheet, AT29LV040A-15JC pinout, AT29LV040A-15JC application, or AT29LV040A-15JC equivalent, key selection criteria include sector-based programming timing (20 ms max), DATA polling and toggle-bit end-of-program detection, boot block lockout activation sequence, and compatibility with 3.3V microcontroller buses requiring nonvolatile code storage with hardware/software write protection.

Technical Context

The AT29LV040A-15JC implements a sector-erase architecture where each 256-byte sector is erased and programmed in a single internal cycle, using latched address/data and an on-chip timer. Programming requires a three-byte unlock sequence (AAh→55h→A0h) followed by byte loads within 150 µs intervals.

It supports two distinct protection mechanisms: software data protection (3-byte command + sector load) and hardware safeguards including VCC sense (<1.8V inhibition), 10 ms power-on delay, and noise filtering (<15 ns pulse rejection). Boot block lockout is activated via a seven-command sequence and disables chip erase when enabled.

Key Specifications

Pinout & Package

AT29LV040A-15JC is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC), JEDEC MS-016 compliant, with 1.27 mm pitch and 12.45 mm × 14.95 mm body size. Pin 1 identifier is a corner chamfer.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SST39VF400A-70-4C-NHE and MX29LV400CBTI-70G, the AT29LV040A-15JC offers proven boot block lockout with deterministic 150 ns timing and PLCC-32 footprint compatibility for legacy board reuse - but lacks CFI and has slower access than alternatives.

Availability

AT29LV040A-15JC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy PC BIOS retention, and telecom line card bootloader applications requiring stable component supply and long-lifecycle support.

Supply support for AT29LV040A-15JC 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, nonvolatile memory, and security ICs, with design centers across the US, Europe, and Asia.

The AT29LV040A belongs to Atmel's 3.3V-only Flash memory product line, engineered for embedded systems requiring in-system programmability, sector-level erasure, and robust write protection - targeting legacy industrial, computing, and communications platforms.

FAQ

What is the maximum read access time specified for the AT29LV040A-15JC?

The AT29LV040A-15JC has a maximum read access time of 150 ns, measured from address valid to valid data on I/O0–I/O7 under VCC = 3.3V ±0.3V and TA = 0°C to 70°C. This value is guaranteed for the -15 speed grade and defines the minimum clock period for synchronous read operations in microcontroller interfaces.

Does the AT29LV040A-15JC support hardware reset-based programming protection?

Yes, the AT29LV040A-15JC includes multiple hardware protections: VCC sense circuitry disables programming if supply drops below ~1.8V; a 10 ms internal power-on delay prevents writes during startup; and noise filters reject pulses shorter than 15 ns on WE or CE. These operate independently of software commands and remain active across power cycles.

How is boot block lockout enabled on the AT29LV040A-15JC?

Boot block lockout on the AT29LV040A-15JC is enabled via a seven-command software sequence: AAh→55h→80h→AAh→55h→40h→00h at address 00000h (lower block) or FFh at FFFFFh (upper block), with 20 ms pauses between final steps. Once set, the lockout is irreversible and disables chip erase functionality.

Can the AT29LV040A-15JC be used with 5V-tolerant microcontrollers?

Yes - the AT29LV040A-15JC accepts 0–5.5V on address and control inputs (A0–A18, CE, OE, WE) while operating from a 3.3V supply, enabling direct interfacing with 5V-tolerant microcontrollers like the 80C188 or older ARM7 derivatives without level shifters. However, I/O0–I/O7 must not exceed 3.6V.

What is the sector erase mechanism used in the AT29LV040A-15JC?

The AT29LV040A-15JC performs automatic sector erase prior to programming: once the 3-byte unlock sequence is issued and 256 bytes are loaded into the internal latch, the device internally erases the target 256-byte sector before programming the new data. No separate erase command is required, and the entire process completes within 20 ms.