Microchip Technology AT17N256-10SC

Overview

AT17N256-10SC from Atmel is a 256-Kbit serial EEPROM FPGA configuration memory designed for Master Serial mode loading of Xilinx 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 10 write cycles endurance with 20-year data retention at 85°C.

For engineers reviewing the AT17N256-10SC datasheet, AT17N256-10SC pinout, AT17N256-10SC application, or AT17N256-10SC 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 AT17N256-10SC 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 two DC pins (internally connected but not bonded), VCC(SER_EN) and VCC power pins separated for programming isolation, and CE/RESET/OE logic enabling precise control over data output timing and standby entry-critical for deterministic FPGA startup sequences.

Key Specifications

Pinout & Package

AT17N256-10SC is packaged in a 20-lead SOIC (JEDEC 20S2), 0.300" wide body, with 0.050" 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 AT17N256-10SC, AT17LV256-10SC offers broader voltage flexibility and slightly lower standby draw but shares identical timing and footprint-while XC17S256D trades reprogrammability for OTP simplicity and lower unit cost in static configurations.

Availability

AT17N256-10SC is available at Aetrix Electronics and suitable for industrial motor control, medical imaging subsystems, satellite communication terminals, and legacy telecom infrastructure requiring stable component supply across extended product lifecycles.

Supply support for AT17N256-10SC 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 programmable logic devices before its acquisition by Microchip Technology in 2016.

The AT17N series was developed specifically to provide cost-effective, pin-compatible EEPROM-based configuration memory for Xilinx Spartan-family FPGAs, targeting industrial and communications equipment with long-lifecycle requirements.

FAQ

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

The AT17N256-10SC serves as a serial configuration EEPROM that stores and delivers the bitstream required to configure Xilinx Spartan-II, Spartan-IIE, and Spartan XL FPGAs in Master Serial mode. It interfaces directly with FPGA control signals (CCLK, DIN, INIT_B) and eliminates the need for external controllers during power-up initialization. Its design ensures deterministic, low-jitter bitstream delivery critical for reliable FPGA startup. The AT17N256-10SC is not a general-purpose memory but a purpose-built configurator optimized for FPGA boot sequencing.

Can the AT17N256-10SC be used with modern Xilinx 7-series or UltraScale FPGAs?

No, the AT17N256-10SC is not compatible with Xilinx 7-series or UltraScale FPGAs. It was explicitly designed for Spartan-II, Spartan-IIE, and Spartan XL families and relies on their specific Master Serial protocol, pin assignments, and timing parameters. Newer FPGAs use different configuration schemes (e.g., SelectMAP, JTAG, or QSPI flash interfaces) and require configuration memories with higher densities, faster interfaces, or different voltage tolerances. Using AT17N256-10SC with unsupported FPGAs will result in failed configuration or undefined behavior.

What does the "-10SC" suffix indicate in AT17N256-10SC?

The "-10SC" suffix denotes three key attributes: "-10" specifies the speed grade (10 MHz maximum clock frequency), "S" indicates the 20-lead SOIC package (20S2), and "C" identifies the commercial temperature range (0°C to +70°C). However, per the official Atmel ordering table, AT17N256-10SC is explicitly listed for commercial operation-but the device's full industrial qualification (–40°C to +85°C) is confirmed in the Absolute Maximum Ratings and Operating Conditions sections of the datasheet. This reflects Atmel's dual-rating practice where the "C" suffix denotes the tested grade, not an absolute limitation.

Is the AT17N256-10SC reprogrammable in-circuit, and what conditions are required?

Yes, the AT17N256-10SC supports in-system programming (ISP) via its Two-Wire Serial interface, enabled by pulling the SER_EN pin low. During ISP, the device accepts programming commands and data through the DATA and CLK pins using standard I²C-like protocol. Programming occurs at the nominal VCC supply (3.3V); no external high-voltage programming signals are needed because internal charge pumps generate required voltages. The AT17N256-10SC must be powered and accessible via its programming pins-no removal from the PCB is necessary.

How does the AT17N256-10SC handle power-up and reset sequencing with the FPGA?

Upon power-up, the AT17N256-10SC automatically resets its internal address counter, placing the DATA output in high-impedance state until enabled by CE and RESET/OE. The FPGA initiates configuration by asserting CE low and toggling CLK; RESET/OE is typically held high to enable output. The AT17N256-10SC requires no external reset coordination-the FPGA controls the entire sequence. Its power-on reset behavior is fully compliant with Spartan-II Master Serial timing requirements, including guaranteed counter reset and data float delay (TDF ≤ 55 ns) to prevent bus contention during startup.