Microchip Technology AT17N256-10NI

Overview

AT17N256-10NI from Microchip Technology (formerly 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 10 write cycles endurance with 20-year data retention at 85°C.

For engineers reviewing the AT17N256-10NI datasheet, AT17N256-10NI pinout, AT17N256-10NI application, or AT17N256-10NI 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 AT17N256-10NI implements a synchronous serial interface where CLK drives internal address/bit counters, DATA provides tri-state open-collector output for FPGA DIN, and RESET/OE controls counter reset and output enable. SER_EN must be tied high during FPGA configuration to disable ISP mode and activate standard serial read operation.

Its control logic directly interfaces with SRAM-based FPGA master serial pins: CCLK → CLK, DIN ← DATA, and FPGA-driven CE/RESET/OE manage output enable and counter reset. Standby mode is entered when CE is high, reducing ICCS to ≤100 µA in industrial grade - critical for power-sensitive embedded reconfiguration circuits.

Key Specifications

Pinout & Package

AT17N256-10NI is packaged in an 8-lead SOIC (8S1) per JEDEC MS-012, Variation AA, with 0.150" body width and gull-wing leads. Pin 1 identifier is marked by a notch or dot; package dimensions comply with A1 = 0.10–0.25 mm, body thickness A2 = 1.00 mm nominal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT17N256-10NI, AT17LV256-10NI offers higher endurance and broader voltage tolerance but same industrial temperature support and pin compatibility, while XC17S255A trades reprogrammability for permanent configuration security - making AT17N256-10NI the optimal balance of field update capability, reliability, and legacy design continuity.

Availability

AT17N256-10NI is available at Aetrix Electronics and suitable for industrial PLCs, motor drive controllers, and legacy telecom infrastructure requiring stable component supply with long-term lifecycle assurance.

Supply support for AT17N256-10NI 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 AT17N series.

The AT17N series was designed specifically for cost-effective, pin-compatible replacement of Xilinx XC17S PROMs in Spartan-family FPGA systems, emphasizing industrial reliability, low-power serial configuration, and seamless integration into master serial boot architectures.

FAQ

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

The AT17N256-10NI serves as a serial configuration EEPROM that stores and delivers the bitstream to SRAM-based FPGAs such as Spartan-II, Spartan-IIE, and Spartan XL in Master Serial mode. It eliminates the need for external controllers by allowing the FPGA to autonomously load its configuration upon power-up or reset, using dedicated control signals (CLK, CE, RESET/OE) and DATA output synchronized to the FPGA's CCLK. Its role is strictly nonvolatile boot memory - not runtime data storage or logic execution.

Is the AT17N256-10NI pin-compatible with Xilinx XC17S series PROMs?

Yes, the AT17N256-10NI is explicitly documented as pin-compatible with Xilinx XC17SXXXA and XC17SXXXXL PROMs. This includes identical 8-lead SOIC pin assignments for DATA, CLK, RESET/OE, CE, VCC, GND, and SER_EN/VCC functions. The compatibility extends to AC timing parameters and DC electrical characteristics, enabling direct PCB-level replacement in legacy Spartan-II designs without layout modification.

Can the AT17N256-10NI be reprogrammed in-system (ISP)?

Yes, the AT17N256-10NI supports in-system programming via its Two-Wire Serial interface. When SER_EN is pulled low, the device enters ISP mode and accepts programming commands through the DATA and CLK pins. This allows field updates without removing the device from the board. However, ISP requires external programming hardware (e.g., Atmel ATDH2225 cable) and is distinct from normal FPGA configuration operation, which requires SER_EN tied high.

What is the maximum clock frequency supported by the AT17N256-10NI during FPGA configuration?

The AT17N256-10NI supports a maximum clock frequency of 10 MHz in both commercial and industrial grades. This is confirmed by the AC characteristic FMAX parameter, with corresponding timing limits: TCAC (CLK to Data Delay) ≤80 ns and TCE (CE to Data Delay) ≤60 ns. These values ensure reliable synchronization with Spartan-II FPGA CCLK inputs under worst-case industrial temperature and voltage conditions.

Does the AT17N256-10NI require external decoupling capacitors?

Yes, the AT17N256-10NI requires a 0.2 µF decoupling capacitor between VCC and GND, as specified in the Pin Description section. This capacitor stabilizes the 3.3V supply during output transitions and reduces noise coupling into the sensitive serial interface, especially critical for reliable bitstream delivery to the FPGA. Placement should be adjacent to the VCC/GND pins on the PCB to minimize inductance.