Microchip Technology AT27C1024-15PC

Overview

AT27C1024-15PC from Atmel is a 1-Mbit (64K × 16) one-time programmable EPROM with 40-pin PDIP package, 150 ns read access time, 5V ±10% supply, and dual-line control (CE/OE). It serves as nonvolatile firmware storage in legacy 16-bit microprocessor systems requiring reliable boot code retention without battery backup.

For engineers reviewing the AT27C1024-15PC datasheet, AT27C1024-15PC pinout, AT27C1024-15PC application, or AT27C1024-15PC equivalent, key selection factors include verified 150 ns tACC timing at industrial temperature range, VPP-programmable OTP architecture, JEDEC-standard 40P6 PDIP footprint, and compatibility with Rapid™ programming algorithms at 100 µs/word.

Technical Context

The AT27C1024-15PC implements a CMOS-based OTP memory array organized as 64K words × 16 bits, accessed via 16 address lines (A0–A15) and 16 bidirectional data outputs (O0–O15). Its two-line enable architecture (CE and OE) enables bus contention avoidance in high-speed parallel bus systems.

Programming requires VPP = 13.0 V ±0.25 V and VCC = 6.5 V ±0.25 V, with a 100 µs PGM pulse width and verification loop per word. Product identification uses A9 voltage sensing (12.0 V ±0.5 V) and A0 toggling to select manufacturer or device code.

Key Specifications

Pinout & Package

AT27C1024-15PC uses a 40-lead, 0.600" wide plastic dual inline package (PDIP, JEDEC MS-011 AC), with dual GND pins (pins 12 and 29) requiring connection for ESD and latchup immunity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar OTP EPROM applications.

Compared with AT27C1024-15PC, AT27C512-15PC halves data bus width and doubles chip count for 16-bit systems, while MX27C1024PC-15 matches pinout and speed but sacrifices programmability intelligence and verification efficiency.

Availability

AT27C1024-15PC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy embedded boot ROM, and military avionics configuration memory requiring stable component supply across extended product lifecycles.

Supply support for AT27C1024-15PC 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) designed high-reliability nonvolatile memory and microcontroller solutions for industrial, automotive, and aerospace applications.

The AT27C1024 product line delivers OTP EPROMs optimized for deterministic boot code execution in 16-bit microprocessor systems where firmware immutability, long-term data retention, and JEDEC-standard packaging are critical.

FAQ

What is the maximum read access time specified for AT27C1024-15PC?

The AT27C1024-15PC has a maximum read access time (tACC) of 150 ns under industrial temperature conditions (-40°C to +85°C) with VCC = 5 V ±10%. This value is guaranteed across the full operating range and defines the minimum address-to-data valid delay in CPU interface timing budgets. The "-15" suffix explicitly denotes this 150 ns speed grade, distinguishing it from faster variants like the -12 (120 ns) or slower ones like the -90 (90 ns).

Does AT27C1024-15PC require a high-voltage supply for normal operation?

No, AT27C1024-15PC operates in read mode using only a single 5 V ±10% supply (VCC). The VPP pin is used exclusively during programming and must be set to 13.0 V ±0.25 V; it is tied to VCC (5 V) during read or standby modes. Applying VPP = 13 V during read operation will damage the device. The datasheet mandates that VCC be applied before and removed after VPP during programming sequences.

Can AT27C1024-15PC be used as a direct replacement for AT27C516 in existing designs?

Yes, AT27C1024-15PC is documented as a direct upgrade from the 512K AT27C516, sharing the same 40-lead PDIP package (40P6), pinout, and 5 V operation. However, its 64K × 16 organization differs from AT27C516's 64K × 8 structure - requiring bus-width alignment in the host system. No PCB changes are needed, but address/data bus routing and firmware addressing logic must accommodate the doubled word size.

What decoupling capacitors are required for stable operation of AT27C1024-15PC?

Each AT27C1024-15PC requires a 0.1 µF high-frequency ceramic capacitor placed between VCC and GND, mounted as close as possible to pins 21 (VCC) and 12/29 (GND). For boards with multiple EPROMs, a 4.7 µF bulk electrolytic capacitor must also be connected between VCC and GND near the power entry point. These values are mandated in the "System Considerations" section to suppress transient excursions during CE switching and ensure reliable 150 ns timing.

How is the product identification code read from AT27C1024-15PC?

The AT27C1024-15PC integrates a manufacturer ID (001Eh) and device code (00F1h) accessible via voltage-controlled addressing: A9 is driven to 12.0 V ±0.5 V (VID), A0 is toggled between low and high while all other address lines (A1–A15) remain at VIL, and outputs O15–O0 reflect the corresponding 16-bit ID word. This feature enables automatic detection by industry-standard programmers and eliminates manual part selection errors during production programming.