Microchip Technology AT29C020-70JC

Overview

AT29C020-70JC from Atmel is a 2-megabit (256K × 8) 5-volt-only Flash memory IC organized as 262,144 bytes, featuring 70 ns read access time, sector-based reprogramming (1024 sectors × 256 bytes), hardware/software data protection, and two 8K-byte boot blocks with independent lockout-used in embedded system firmware storage and BIOS/UEFI code retention.

For engineers reviewing the AT29C020-70JC datasheet, AT29C020-70JC pinout, AT29C020-70JC application, or AT29C020-70JC equivalent, key selection considerations include its PLCC-32 package, 5V ±10% single-supply operation, CMOS/TTL compatibility, industrial temperature range (–40°C to +85°C), and sector-program timing constraints for in-system reprogramming.

Technical Context

The AT29C020-70JC implements sector-erase-and-program architecture with internal address/data latches for 256-byte loads, automatic erase-and-program sequencing controlled by an on-chip timer, and dual detection methods-DATA polling on I/O7 and TOGGLE BIT on I/O6-for program cycle completion. It supports byte-load operations via WE- or CE-controlled pulses with strict 150 µs inter-byte timing.

Hardware data protection includes VCC sense (<3.8 V inhibits programming), 5 ms power-on delay, noise filtering (<15 ns pulse rejection), and active-level inhibition (OE low, CE high, or WE high blocks writes). Software protection uses a three-command sequence (AAh/55h/A0h at 5555h/2AAAh/5555h) to enable/disable write locks, independent of power cycles.

Key Specifications

Pinout & Package

AT29C020-70JC is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32), JEDEC MS-016 compliant, with 1.27 mm pitch, 12.45 mm × 14.95 mm body, and pin 1 identifier at corner notch. Pin layout supports standard 5V parallel memory bus interfacing with no level-shifting required.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AM29LV040B-70JC and MX29LV040CTTI-70G, the AT29C020-70JC uniquely delivers 5 V-only operation, dedicated 8K boot blocks with independent lockout, and software/hardware dual-protection - making it irreplaceable in legacy 5 V systems requiring guaranteed bootloader immutability and field-programmability without voltage translation.

Availability

AT29C020-70JC 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 across extended product lifecycles.

Supply support for AT29C020-70JC 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, nonvolatile memory, and security ICs for industrial, automotive, and consumer applications.

The AT29C020-70JC belongs to Atmel's legacy parallel Flash memory product line, designed specifically for 5V embedded systems requiring in-system reprogrammability, robust data retention, and hardware-enforced write protection in harsh environments.

FAQ

What is the maximum operating temperature range for the AT29C020-70JC?

The AT29C020-70JC is rated for industrial temperature operation from –40°C to +85°C. This specification is confirmed in the "DC and AC Operating Range" table of the official datasheet (Rev. 0291N–FLASH–07/02), where the "I" suffix in the ordering code denotes industrial grade. The device maintains full functionality-including 70 ns read access and 10 ms sector programming-across this full range.

Does the AT29C020-70JC require external high-voltage programming signals?

No, the AT29C020-70JC does not require external high-voltage programming signals. As stated in the datasheet description, it is a "5-volt-only in-system Flash programmable" device. All programming operations-including sector erase and byte load-are executed using only the standard 5 V ±10% VCC supply. Internal circuitry handles voltage boosting, eliminating the need for 12 V or other auxiliary programming voltages.

How many sectors does the AT29C020-70JC contain, and what is the size of each sector?

The AT29C020-70JC contains 1024 sectors, each sized at 256 bytes. This is explicitly stated in the "Features" section and verified in the "Device Operation" section under "PROGRAM", which specifies that "A8 to A17 specify the sector address" and "256 bytes of data are loaded into the device and then simultaneously programmed." The total capacity (1024 × 256 = 262,144 bytes) matches the 2 Mbit (256K × 8) organization.

Can the boot blocks of the AT29C020-70JC be independently locked and unlocked?

Yes, the AT29C020-70JC provides independent programming lockout for its two 8K-byte boot blocks-one at the lowest addresses (0x00000–0x01FFF) and one at the highest (0x3E000–0x3FFFF). The "BOOT BLOCK PROGRAMMING LOCKOUT" section confirms that "the programming lockout feature can be set independently for either block," and the enable algorithm specifies separate commands to lock the lower or upper block. Once locked, each block remains immutable until explicitly unlocked via its respective command sequence.

What are the valid methods to detect completion of a program cycle on the AT29C020-70JC?

The AT29C020-70JC supports two hardware-confirmed methods to detect program cycle completion: DATA polling on I/O7 (where the bit toggles to complement of loaded data until completion) and TOGGLE BIT monitoring on I/O6 (which alternates between 0 and 1 during programming and stabilizes upon finish). Both methods are detailed in dedicated sections of the datasheet and do not require external timing components-enabling deterministic, bus-efficient status checking during in-system updates.