Microchip Technology AT17N256-10SI

Overview

AT17N256-10SI from Atmel is a 256-Kbit serial EEPROM FPGA configuration memory designed for Master Serial mode loading of Spartan-II, Spartan-IIE, and Spartan XL FPGAs. It operates at 3.3V ±10%, supports industrial temperature range (−40°C to +85°C), delivers ≤50 µA standby current, and features 10k write cycles with 20-year data retention at 85°C.

For engineers reviewing the AT17N256-10SI datasheet, AT17N256-10SI pinout, AT17N256-10SI application, or AT17N256-10SI equivalent, this device serves as a drop-in replacement for Xilinx XC17SXXXA/L PROMs in legacy FPGA configuration systems requiring reliable, low-power, nonvolatile serial boot memory with verified timing compliance up to 10 MHz clock frequency.

Technical Context

The AT17N256-10SI implements a synchronous serial interface where CLK increments an internal address counter, DATA provides tri-state open-collector output for FPGA DIN, and RESET/OE controls both counter reset and output enable. SER_EN must be tied high during normal FPGA configuration to disable ISP mode.

It uses a dedicated 20-lead SOIC package (20S2) with dual VCC pins-one for core logic (VCC), one for serial enable (VCC(SER_EN))-and includes NC/DC pins for mechanical compatibility across density variants. Standby mode is activated by CE high, reducing ICCS to ≤100 µA in industrial grade.

Key Specifications

Pinout & Package

AT17N256-10SI is packaged in a 20-lead SOIC (JEDEC 20S2), 0.300" wide body, with 1.27 mm lead pitch. Pin 1 identifier is marked by a notch or dot; package dimensions comply with JEDEC MS-012 Variation AA.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT17N256-10SI, AT17LV256-10SI offers higher endurance and wider voltage range while maintaining pin and function compatibility, whereas XC17S256D provides OTP assurance at the cost of reprogrammability - making the former ideal for upgrade paths and the latter for fixed-deployment security.

Availability

AT17N256-10SI is available at Aetrix Electronics and suitable for industrial automation, legacy FPGA-based test equipment, and avionics data acquisition units requiring stable component supply amid ongoing obsolescence management.

Supply support for AT17N256-10SI 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

Atmel Corporation was a U.S.-based semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and FPGA configuration solutions before its acquisition by Microchip Technology in 2016.

The AT17N series was designed specifically to provide cost-effective, pin-compatible EEPROM-based configuration memory for Xilinx Spartan-family FPGAs in industrial and communications infrastructure applications.

FAQ

What is the primary function of the AT17N256-10SI in an FPGA system?

The AT17N256-10SI serves as a serial configuration EEPROM that loads bitstream data into SRAM-based FPGAs such as Xilinx Spartan-II, Spartan-IIE, and Spartan XL devices during power-up in Master Serial mode. It replaces OTP PROMs with reprogrammable EEPROM technology, enabling field updates and eliminating the need for external controllers. The AT17N256-10SI interfaces directly with FPGA control signals (CCLK, DIN, INIT_B) using only five essential pins: DATA, CLK, CE, RESET/OE, and SER_EN.

Which FPGA families and models are explicitly supported by the AT17N256-10SI?

The AT17N256-10SI is explicitly compatible with Xilinx Spartan-II, Spartan-IIE, and Spartan XL FPGAs when configured in Master Serial mode. It is also pin-compatible with Xilinx XC17SXXXA and XC17SXXXXL PROMs, allowing direct substitution in existing designs. Documentation confirms interoperability with specific devices including XC2S50, XC2S100, and XC2S150, provided the FPGA's configuration mode pins are set correctly and the bitstream size does not exceed 256 Kbit.

What package type and pin count does the AT17N256-10SI use?

The AT17N256-10SI uses a 20-lead SOIC package (JEDEC designation 20S2), 0.300" wide body, with 1.27 mm lead pitch. This matches the package used for AT17N512-10SI and AT17N010-10SI variants. The 20-pin layout includes eight NC pins, two VCC pins (VCC and VCC(SER_EN)), one GND, and dedicated control/data lines - all documented in Atmel's 3020C–CNFG–08/07 datasheet Figure 2.

Can the AT17N256-10SI be programmed in-system, and what is required?

Yes, the AT17N256-10SI supports in-system programming (ISP) via its Two-Wire Serial interface, enabled by pulling the SER_EN pin low. Programming requires a compatible programmer such as Atmel's ATDH2225 ISP Cable or industry-standard tools supporting the AT17N command set. VCC must be stable at 3.3V ±10%; no external high-voltage supply is needed, as internal charge pumps generate programming voltages. The AT17N256-10SI retains full functionality in normal operation when SER_EN is tied high.

How does the AT17N256-10SI handle power-down and low-power states?

The AT17N256-10SI enters low-power standby mode automatically when the CE pin is driven high, drawing ≤100 µA at 3.3V and −40°C to +85°C. During standby, the internal address counter halts and the DATA pin is tri-stated. Power-on reset initializes the counter to zero. No external reset circuitry is required - the FPGA's INIT_B or similar signal can drive RESET/OE to synchronize configuration start. The AT17N256-10SI maintains stored data without refresh across power cycles.