Microchip Technology AT29LV1024-20JC

Overview

AT29LV1024-20JC from Atmel is a 3.3V-only, 1 Mbit (64K × 16) Flash memory IC designed for in-system reprogrammability in embedded firmware storage applications. It features 150 ns read access time, 20 ms sector program cycle time, 512 sectors (128 words/sector), 15 mA active current, and 50 µA CMOS standby current, operating across commercial temperature range (0°C to 70°C) in a 44-lead PLCC package.

For engineers reviewing the AT29LV1024-20JC datasheet, AT29LV1024-20JC pinout, AT29LV1024-20JC application, or AT29LV1024-20JC equivalent, this device serves as a drop-in upgrade path from EPROM-based boot code storage where low-voltage operation, sector-level erase flexibility, and software data protection are required without high-voltage programming circuitry.

Technical Context

The AT29LV1024-20JC implements a sector-erase architecture with internal latching of 128-word sectors during programming, enabling bus release for concurrent operations. Its software data protection requires a three-command sequence (5555h/2AAAh/A0A0h) before any sector load, preventing inadvertent writes during power transitions or noise events.

It supports DATA polling (I/O7/I/O15 complement detection) and Toggle Bit (I/O6/I/O14 toggling) for end-of-program verification, and includes hardware safeguards: VCC sense (<1.8V inhibits programming), 10 ms power-on delay, and noise filtering (<15 ns pulses rejected on WE/CE). Inputs tolerate 0–5.5V while I/Os operate at 0–3.6V under 3.3V ±10% supply.

Key Specifications

Pinout & Package

AT29LV1024-20JC is packaged in a 44-lead Plastic J-Leaded Chip Carrier (PLCC), JEDEC MS-018 AC compliant, with 1.27 mm pitch and body size 16.5 mm × 16.5 mm. Pin 1 is marked by a corner notch; NC pins are internally unconnected and must be left floating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SST39VF100A-20-4C-NHE, AT29LV1024-20JC offers superior power-loss immunity via VCC sense and automatic 10 ms delay, while MX29LV102CTTI-20G provides direct thermal upgrade path without layout change - both require firmware adaptation for command-set differences.

Availability

AT29LV1024-20JC is available at Aetrix Electronics and suitable for industrial control systems, network infrastructure equipment, and medical instrumentation requiring stable component supply with long lifecycle visibility and consistent PLCC-44 packaging.

Supply support for AT29LV1024-20JC 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 for embedded systems.

The AT29LV1024 product line delivers 3.3V-only Flash memory optimized for in-system reprogrammability in space-constrained, low-power embedded applications where EPROM replacement and firmware field updates are essential.

FAQ

What is the maximum operating frequency supported by AT29LV1024-20JC?

The AT29LV1024-20JC does not specify a maximum clock frequency because it is an asynchronous memory device. Its timing is governed by access and setup/hold parameters - notably tACC ≤ 200 ns and tWP ≥ 200 ns - enabling reliable operation with microcontrollers running up to 5 MHz bus clocks. The device responds to CE/OE/WE control signals rather than a system clock, so timing compliance depends on meeting these AC specifications in the host interface design. AT29LV1024-20JC has been validated in systems with 5 MHz read cycles and 150 µs word-load intervals.

Does AT29LV1024-20JC support full-chip erase?

Yes, AT29LV1024-20JC supports optional full-chip erase via a documented 6-byte software command sequence, in addition to standard sector-erase operation. This mode is intended for complete firmware replacement scenarios and is described in the "Software Chip Erase" application note referenced in the datasheet. Unlike sector erase, chip erase clears all 512 sectors simultaneously and requires the same software data protection unlock sequence prior to execution. AT29LV1024-20JC does not support hardware reset-based chip erase.

Can AT29LV1024-20JC be used with 5V-tolerant microcontrollers?

Yes, AT29LV1024-20JC accepts 0–5.5V on address and control inputs (A0–A15, CE, OE, WE), making it compatible with 5V-tolerant microcontrollers operating at 3.3V I/O levels. However, its I/O0–I/O15 pins are limited to 0–3.6V and must not be driven above that threshold. When interfacing with 5V logic, level-shifting circuitry is required on the bidirectional data bus, while address/control lines may connect directly if the MCU's 5V-tolerant pins are configured for 3.3V operation. AT29LV1024-20JC's input voltage tolerance simplifies integration into mixed-voltage systems.

What is the purpose of the NC pins on AT29LV1024-20JC?

The NC (No Connect) pins on AT29LV1024-20JC - specifically pins 7, 8, 12, 16, 25, 31, 32, 33, 34, 41, 42, and 43 in the PLCC-44 package - are internally unconnected and serve no electrical function. They must be left floating and not tied to VCC, VSS, or any signal. These pins exist for mechanical compatibility with larger-package variants and to maintain standardized PLCC pinout spacing. Connecting them risks unintended coupling or latch-up; AT29LV1024-20JC functionality is fully defined by its 28 active signals (16 I/O, 16 address, 4 controls, 2 power).

How does the software data protection feature work on AT29LV1024-20JC?

The software data protection feature on AT29LV1024-20JC requires a precise three-step command sequence - writing 0xAAAA to address 0x5555, then 0x5555 to address 0x2AAA, then 0xA0A0 to address 0x5555 - before any sector programming is enabled. This sequence must be repeated before each new sector load. The feature remains active until the end of the program cycle, after which it automatically re-engages. AT29LV1024-20JC ignores all write attempts without this sequence, using internal timers to prevent false triggers from noise or power transients - a key reliability mechanism confirmed in the datasheet's Hardware Data Protection section.