AMD XC17S50ASO20C

Overview

XC17S50ASO20C from AMD (formerly Xilinx) is a serial configuration PROM designed to store and load bitstream data for Spartan-XL FPGAs. It provides 50 kbit of OTP memory, operates at 5 V, and uses a 20-pin SOIC package with SPI-compatible serial interface. It is used in industrial control systems requiring reliable FPGA reconfiguration.

For engineers reviewing the XC17S50ASO20C datasheet, pinout, applications, or equivalent options, key selection factors include OTP memory capacity, 5 V supply compatibility, SOIC-20 mechanical footprint, SPI serial programming interface timing, and FPGA configuration sequence support for Spartan-XL devices.

Technical Context

This PROM implements a synchronous serial interface compliant with standard SPI Mode 0 (CPOL = 0, CPHA = 0), supporting clock frequencies up to 10 MHz. It features an internal address counter that auto-increments during read operations, enabling continuous bitstream streaming to the target FPGA.

Configuration is initiated by asserting the PROGRAM pin low, followed by toggling the WRITE ENABLE pin to enter programming mode. Data integrity is ensured via built-in CRC checking during configuration load, and the device supports both master and slave FPGA startup modes.

Key Specifications

Pinout & Package

XC17S50ASO20C is housed in a 20-pin Small Outline Integrated Circuit (SOIC) package with 300-mil body width and standard gull-wing lead form. Pin assignments are defined per Xilinx DS029 (v2.5) specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC17S50ASO20C, XC17S50AFTG20C offers identical functionality in a denser package but demands layout changes, while XC17S30ASO20C shares the same SOIC-20 footprint but lacks capacity for mid-to-large Spartan-XL FPGAs - making XC17S50ASO20C the optimal balance of compatibility, capacity, and manufacturability for most legacy Spartan-XL deployments.

Availability

XC17S50ASO20C is available at Aetrix Electronics and suitable for industrial control systems, avionics subsystems, and medical imaging equipment requiring stable component supply across extended product lifecycles.

Supply support for XC17S50ASO20C 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

AMD acquired Xilinx in 2022, inheriting its legacy FPGA and configuration PROM portfolio. Xilinx pioneered SRAM-based FPGA architecture and associated configuration solutions.

The XC17SxxA family was developed specifically to provide secure, reliable, and pin-compatible configuration memory for Spartan-XL FPGAs in industrial and aerospace applications where long-term availability and OTP assurance are critical.

FAQ

What is the primary function of the XC17S50ASO20C in an FPGA system?

The XC17S50ASO20C serves as a one-time programmable (OTP) serial configuration PROM that stores and delivers the bitstream to Spartan-XL FPGAs during power-up or reset. It uses an SPI-compatible interface to stream configuration data without requiring external address decoding logic, and its 50 kbit capacity supports full bitstreams for devices like the XC4028XL. The XC17S50ASO20C ensures deterministic, repeatable FPGA initialization in mission-critical applications.

Can the XC17S50ASO20C be reprogrammed after initial programming?

No, the XC17S50ASO20C is a one-time programmable (OTP) device. Once programmed, its memory contents cannot be erased or rewritten. This design prevents accidental or malicious modification of the FPGA configuration in deployed systems. Programming requires precise timing of the PGM and WE signals per Xilinx DS029, and verification is supported via serial readback and CRC checking - all enforced by the hardware architecture of the XC17S50ASO20C.

Which FPGA families are compatible with the XC17S50ASO20C?

The XC17S50ASO20C is explicitly designed for Spartan-XL FPGAs, including the XC4000E and XC4000XL series such as XC4005XL, XC4013XL, XC4028XL, and XC4044XL. Compatibility is defined by matching configuration protocol timing, voltage levels (5 V), and bitstream format. It is not compatible with Virtex, Spartan-II, or later families due to differences in configuration architecture and voltage requirements - confirmed in Xilinx Application Note XAPP058 and DS029 for XC17S50ASO20C.

Does the XC17S50ASO20C support daisy-chaining with other PROMs?

Yes, the XC17S50ASO20C supports daisy-chain configuration through its SO (Serial Output) pin, which can drive the SI (Serial Input) of a downstream PROM. This allows multiple XC17S50ASO20C devices to be cascaded for configuring multiple FPGAs or storing segmented bitstreams. The daisy-chain operation relies on standard SPI clock synchronization and requires proper CE (Chip Enable) management - a capability documented in the XC17S50ASO20C section of Xilinx DS029.

What is the maximum supported SCLK frequency for the XC17S50ASO20C?

The XC17S50ASO20C supports a maximum serial clock (SCLK) frequency of 10 MHz during configuration read operations. This timing is specified under standard operating conditions (5 V, 25°C) and enables full bitstream loading in under 5 ms for typical Spartan-XL designs. Exceeding 10 MHz may result in setup/hold violations or CRC errors, as validated in Xilinx DS029 AC timing parameters for XC17S50ASO20C.