Microchip Technology AT29BV020-12TU

Overview

AT29BV020-12TU from Atmel is a 2.7V-only, 2 Mbit (256K × 8) in-system Flash PEROM with 120 ns read access time, 20 ms max sector program cycle, and dual 8K-byte boot blocks with independent programming lockout. It operates across -40°C to +85°C, supports software data protection via three-byte command sequence, and delivers 15 mA active current and 50 µA CMOS standby current for embedded firmware storage in microcontroller-based systems.

For engineers reviewing the AT29BV020-12TU datasheet, AT29BV020-12TU pinout, AT29BV020-12TU application, or AT29BV020-12TU equivalent, key selection considerations include its single 2.7–3.6V supply operation, sector-based reprogramming (256 bytes/sector), DATA polling and toggle-bit end-of-program detection, and hardware-level VCC-sense and noise-filtering protections against inadvertent writes.

Technical Context

The AT29BV020-12TU implements a sector-erase-and-program architecture where each of 1024 sectors (256 bytes) is internally latched before simultaneous programming, eliminating need for external erase commands. Its software data protection requires a precise 3-byte command sequence (AAh→55h→A0h at specific addresses) to enable write cycles - a deterministic state-machine flow validated by hardware VCC sense and 10 ms power-on delay.

It features dual boot blocks (first and last 8K bytes) with independent lockout activation via a 7-command algorithm; once enabled, locked blocks prevent erasure or programming and disable chip-erase functionality. Read operations mirror EPROM timing, with CE/OE dual-control enabling bus contention avoidance, while I/O6 toggle-bit and I/O7 DATA polling provide real-time program status without dedicated status registers.

Key Specifications

Pinout & Package

AT29BV020-12TU is available in 32-lead TSOP (Type 1, package code 32T), measuring 20.0 mm × 8.0 mm × 1.2 mm, with gull-wing leads and JEDEC MO-142 BD compliance. Pin 1 identifier is marked by a beveled corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT29BV020-12TU, SST39VF200A offers faster read speed but no hardware boot lockout, while MX29LV200CTTI matches boot protection functionality but requires revalidation of unlock sequences and timing margins in existing firmware.

Availability

AT29BV020-12TU is available at Aetrix Electronics and suitable for industrial PLC firmware storage, medical device bootloader retention, and automotive body control module configuration requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AT29BV020-12TU 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 fabless semiconductor company specializing in microcontrollers, Flash memory, and secure authentication ICs for embedded systems.

The AT29BV020-12TU belongs to Atmel's Low Voltage Flash family, designed specifically for in-system reprogrammability in resource-constrained 8-bit and 16-bit microcontroller platforms where single-supply simplicity and sector-level firmware agility are critical.

FAQ

What is the maximum read access time specified for the AT29BV020-12TU?

The AT29BV020-12TU has a maximum read access time of 120 ns, measured from address valid to valid data on I/O0–I/O7 when CE and OE are asserted low and WE is high. This timing is guaranteed across the full industrial temperature range (-40°C to +85°C) and 2.7–3.6V supply, enabling direct connection to 8-MHz microcontrollers without wait-state insertion. The "-12" suffix in AT29BV020-12TU explicitly denotes this 120 ns speed grade.

How does software data protection work in the AT29BV020-12TU?

Software data protection in the AT29BV020-12TU requires a precise three-byte command sequence: write AAh to address 5555h, then 55h to 2AAAh, then A0h to 5555h. Only after this sequence is completed can subsequent byte loads initiate programming. The AT29BV020-12TU validates each command in order; any deviation resets the protection state. This mechanism prevents accidental writes during power-up, noise events, or firmware errors without requiring external hardware controls.

Can the AT29BV020-12TU be used with a 5V microcontroller interface?

Yes - the AT29BV020-12TU accepts input voltages up to 5.5V on address and control pins (A0–A17, CE, OE, WE) while operating from a 2.7–3.6V VCC supply, making it compatible with 5V-tolerant 8051 or Z80 systems. However, I/O0–I/O7 pins are limited to 0–(VCC + 0.6V); thus, level-shifting is required for bidirectional data transfer with 5V logic. Direct connection is safe only for read operations with 5V-tolerant MCU inputs.

What happens when the boot block lockout feature is activated on the AT29BV020-12TU?

When activated, the boot block lockout feature permanently prevents erasure or programming of the designated 8K-byte region (either lower block at 0x00000 or upper block at 0x3E000). Once locked, the corresponding block retains its contents indefinitely, and the chip-erase function becomes disabled. The AT29BV020-12TU provides software detection via reads from 0x00002h (lower block) or 0x3FFF2h (upper block): FFh indicates lockout active, FEh means unlocked. No hardware reset restores writability.

Does the AT29BV020-12TU support full-chip erase?

Yes - the AT29BV020-12TU supports full-chip erase via a six-byte software command sequence documented in Atmel's application notes. However, this function is disabled if either boot block has been locked out. Full-chip erase is not required for normal operation since sector erase is automatic prior to programming. The AT29BV020-12TU does not implement hardware chip-erase pins; all erase functions are software-controlled and require valid unlock sequences to execute.