Microchip Technology AT17C65-10SI

Overview

AT17C65-10SI from Microchip Technology (formerly Atmel) is a 64K-bit (65,536 × 1) serial EEPROM FPGA configuration memory designed for master-serial mode loading of SRAM-based FPGAs. It operates at 5V ±10% over –40°C to +85°C, supports in-system programming via 2-wire bus, and features programmable reset polarity and write protection. It is used in industrial embedded FPGA systems requiring reliable, nonvolatile configuration storage.

For engineers reviewing the AT17C65-10SI datasheet, AT17C65-10SI pinout, AT17C65-10SI application, or AT17C65-10SI equivalent, key selection criteria include industrial temperature support, 5V operation, cascading capability (as end-of-chain only), CEO output behavior, and compatibility with Xilinx XC3000/XC4000, Altera FLEX®, and Atmel AT40K/AT6000 FPGAs.

Technical Context

The AT17C65-10SI implements a serial-access configuration memory architecture optimized for FPGA master-serial boot. Its internal address counter advances on CLK edges, synchronized to FPGA CCLK, and resets on active RESET/OE or power-up. The device uses open-collector DATA I/O with three-state control via CE and RESET/OE, and includes a programmable reset polarity byte stored in EEPROM.

It supports two operational modes: configuration mode (SER_EN = High) for FPGA boot, and 2-wire serial programming mode (SER_EN = Low) for in-system reprogramming. CEO output is asserted low after final bit read and enables daisy-chaining only when used with AT17C128/256 devices - the AT17C65-10SI itself functions only as standalone or cascade endpoint.

Key Specifications

Pinout & Package

AT17C65-10SI is supplied in a 20-lead PLCC (Plastic Leaded Chip Carrier) package per JEDEC MS-018 AA, with 1.27 mm pitch, 9.02 mm × 9.02 mm body, and J-leads suitable for through-hole or surface-mount assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT17LV65-10SI, the AT17C65-10SI provides higher clock tolerance (12.5 MHz vs. 10 MHz) and 5V compatibility essential for legacy industrial FPGAs; compared with XCR3064XL-10VQG44C, it retains the simplicity of serial configuration memory without requiring CPLD logic resources or JTAG infrastructure.

Availability

AT17C65-10SI is available at Aetrix Electronics and suitable for industrial PLCs, Xilinx XC4000-based test equipment, Altera FLEX 10K communications modules, and Atmel AT40K aerospace subsystems requiring stable component supply across extended lifecycle demands.

Supply support for AT17C65-10SI 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

Microchip Technology acquired Atmel in 2016 and maintains full support for legacy Atmel FPGA configuration products including the AT17 series.

The AT17 series was designed specifically to provide cost-effective, serial, nonvolatile configuration memory for SRAM-based FPGAs operating in industrial and commercial environments - emphasizing ease of interface, in-system programmability, and broad FPGA vendor compatibility.

FAQ

What is the primary function of the AT17C65-10SI in an FPGA system?

The AT17C65-10SI serves as a dedicated serial configuration EEPROM that stores and delivers the bitstream required to initialize SRAM-based FPGAs such as Xilinx XC4000 or Altera FLEX 10K in master-serial mode. It loads configuration data synchronously to the FPGA's CCLK signal, ensuring deterministic startup. The AT17C65-10SI is not a general-purpose memory but a purpose-built configurator with timing and interface logic optimized for FPGA boot sequences.

Can the AT17C65-10SI be used in a cascaded configuration chain with other AT17 devices?

No - the AT17C65-10SI can only be used as a standalone device or at the end of a cascade chain. Only AT17C/LV128 and AT17C/LV256 devices generate the CEO signal needed to enable subsequent EEPROMs in a daisy chain. The AT17C65-10SI's CEO pin functions solely as an output for downstream enablement and cannot accept CEO input, making it incompatible as an intermediate node in multi-device chains.

What does the "-10SI" suffix indicate in AT17C65-10SI?

The "-10SI" suffix denotes three key attributes: "10" specifies a 10 ns access-time grade (reflected in AC parameters like TOE ≤35 ns), "S" indicates SOIC packaging (20-lead, 0.300" wide), and "I" signifies industrial temperature range (–40°C to +85°C). This distinguishes it from commercial-grade variants (e.g., -10SC) and PDIP/PLCC versions (e.g., -10PI, -10JI). The AT17C65-10SI is not pin-compatible with 8-pin packages due to differing pin counts and functions.

How is reset polarity configured on the AT17C65-10SI?

Reset polarity on the AT17C65-10SI is programmed into a dedicated EEPROM byte using an industry-standard programmer (e.g., ATDH2200E) or via 2-wire serial programming mode (SER_EN = Low). Once set, the RESET/OE pin operates as either active-High or active-Low - eliminating need for external inverters. This configuration persists across power cycles and is independent of hardware WP or CE states. The AT17C65-10SI datasheet defines the default as active-High unless reprogrammed.

Is the AT17C65-10SI compatible with modern 3.3V FPGA families?

No - the AT17C65-10SI is a 5V-only device (4.5V–5.5V supply) and is not electrically compatible with 3.3V FPGA I/O standards. For 3.3V systems, the functionally equivalent AT17LV65-10SI must be used. Direct substitution risks overvoltage damage to FPGA inputs and violates VOH/VOL specifications. Level-shifting is not recommended due to timing skew and signal integrity impacts on critical CCLK and DATA paths in the AT17C65-10SI interface.