Microchip Technology AT17LV256-10CI

Overview

AT17LV256-10CI from Microchip Technology (formerly Atmel) is a 256-Kbit serial EEPROM FPGA configuration memory designed for reliable, in-system programmable storage of bitstream data for SRAM-based FPGAs. It supports dual-voltage operation (3.3V and 5.0V), features programmable reset polarity, offers 100,000 write cycles, and retains data for 90 years at 85°C (industrial grade). It interfaces directly with Xilinx XC3000/XC4000/Spartan, Altera FLEX/APEX, and Atmel AT40K/AT94K FPGAs in Master Serial mode.

For engineers reviewing the AT17LV256-10CI datasheet, AT17LV256-10CI pinout, AT17LV256-10CI application, or AT17LV256-10CI equivalent, key selection criteria include industrial temperature range (-40°C to +85°C), 8-lead LAP package compatibility with SOIC footprints, cascading support via CEO output, low-power standby current (<100 µA at 3.3V), and verified compatibility with legacy FPGA configuration architectures.

Technical Context

The AT17LV256-10CI operates in two primary modes: FPGA configuration loading (SER_EN = High) and two-wire ISP programming (SER_EN = Low). During configuration, it uses a synchronous serial interface driven by the FPGA's CCLK, with CE, RESET/OE, and CEO controlling address counter enablement, reset behavior, and daisy-chain coordination.

Its internal architecture includes a 262,144 × 1-bit EEPROM array, a programmable reset polarity register (set via four EEPROM bytes), and hardware write protection (WP input active during programming only). The device lacks READY and WP2 pins-features reserved for higher-density variants-and supports cascading only when CEO is present (confirmed for AT17LV256).

Key Specifications

Pinout & Package

AT17LV256-10CI is packaged in an 8-lead Leadless Array Package (LAP), 6 mm × 6 mm × 1 mm body, pin-compatible with standard 8-lead SOIC footprints. This RoHS-compliant, green package enables high-density PCB layouts without lead pitch or height penalties.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT17LV256-10CU, the AT17LV256-10CI offers identical performance and industrial temperature rating but uses traditional leaded packaging; versus incorrectly referenced CPLDs like XCR3064XL-10VQG44C, the AT17LV256-10CI provides dedicated, proven, and electrically matched FPGA configuration storage with cascading and ISP support.

Availability

AT17LV256-10CI is available at Aetrix Electronics and suitable for industrial automation, legacy FPGA system maintenance, and aerospace ground-support equipment requiring stable component supply across extended product lifecycles.

Supply support for AT17LV256-10CI 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 the legacy AT17LV series, including documentation, programming tools, and long-term supply commitments.

The AT17LV series was originally developed by Atmel to provide cost-effective, pin-compatible configuration memory for SRAM-based FPGAs from Xilinx, Altera, and Atmel's own FPGA families-emphasizing ease of integration, industrial reliability, and in-system reprogrammability.

FAQ

What is the maximum clock frequency supported by the AT17LV256-10CI during FPGA configuration?

The AT17LV256-10CI supports a maximum clock frequency of 10 MHz under industrial conditions (3.3V ±10%, -40°C to +85°C), as specified in the AC Characteristics table. This timing aligns with the CCLK requirements of Xilinx XC4000 and Spartan families, ensuring robust setup/hold margins. The device achieves this using internal edge-aligned counters and optimized output drivers-no external timing components are required.

Does the AT17LV256-10CI support daisy-chaining with other configuration EEPROMs?

Yes, the AT17LV256-10CI supports daisy-chaining via its CEO (Chip Enable Output) pin (Pin 7), which asserts Low upon reaching the final memory address. This signal can drive the CE input of the next AT17LV256-10CI (or compatible AT17LV variant) in a cascade, enabling automatic handoff of configuration data across multiple devices without external control logic.

Can the AT17LV256-10CI be used with both 3.3V and 5V FPGA systems?

Yes, the AT17LV256-10CI is explicitly rated for dual-voltage operation: 3.3V (±10%) and 5.0V (±10% industrial). Its VIH/VIL thresholds and output drive strength are validated across both rails, allowing direct interfacing with 3.3V Spartan-3 or 5V XC4000 FPGAs-no level shifters or voltage translators are needed when VCC matches the FPGA's I/O voltage.

What is the purpose of the SER_EN pin on the AT17LV256-10CI?

The SER_EN pin determines operational mode: when held High, the AT17LV256-10CI functions as a standard FPGA configuration EEPROM; when pulled Low, it enters two-wire serial programming mode for in-system reprogramming. For fixed-configuration applications, SER_EN must be tied to VCC-leaving it floating may cause undefined behavior during power-up or configuration.

How does the programmable reset polarity feature work on the AT17LV256-10CI?

The AT17LV256-10CI allows users to configure the RESET/OE pin (Pin 3) as either active-Low RESET (default for Xilinx) or active-High OE (default for Altera) by programming four specific EEPROM bytes during ISP. This setting persists through power cycles and eliminates board-level jumpers or logic gates-ensuring one hardware design supports multiple FPGA vendors' timing conventions.