XC1701 Series 1-Mbit Serial Configuration PROM: Technical Guide and Legacy Support

UTMEL

Published: 14 January 2026 | Last Updated: 14 January 2026

85

XC1701SO20C

XC1701SO20C

Xilinx Inc.

Surface Mount Tube Configuration Proms for FPGAs 1 (Unlimited) OTP Obsolete XC1701

Purchase Guide

Surface Mount Tube Configuration Proms for FPGAs 1 (Unlimited) OTP Obsolete XC1701

Technical analysis of the Obsolete AMD/Xilinx XC1701 OTP PROM. Covers 1Mbit specs, 5V/3.3V logic, legacy programming tools, and replacement options.

Product Introduction

Engineer’s Takeaway

  • Supply Chain Warning: CRITICAL: The XC1701 is classified as Obsolete / End of Life. Sourcing new inventory is extremely difficult; authorized distributors likely have zero stock. Design maintenance should prioritize securing stock from reputable brokers or migrating to modern storage solutions where logic translation permits.

  • Positioning: The XC1701 is a legacy "Series 1700" configuration memory designed specifically to store bitstreams for older Xilinx FPGAs (Spartan and Virtex families).

  • Why it matters: It utilizes a One-Time Programmable (OTP) architecture. Unlike modern EEPROM or Flash-based configuration memories, once the XC1701 is programmed, it cannot be erased. This makes it robust against corruption but unforgiving during the prototyping phase.

  • Market status: Due to its obsolete status, the primary market activity revolves around maintenance of legacy industrial control systems and aerospace hardware that utilize Spartan-II or Virtex-E era FPGAs.

1. Technical Architecture and Core Advantages

The XC1701 serves as a slave serial peripheral in the FPGA configuration chain. It simplifies the boot process by serializing the 1-megabit configuration bitstream upon power-up.

  • Core Processing: The device features an internal address counter that increments automatically on every clock cycle provided by the master FPGA (CCLK). This eliminates the need for external address generation logic.

  • Cascadability: A key architectural feature is the ability to cascade multiple XC1700 devices. If a target FPGA requires a bitstream larger than 1 Mbit, the CEO (Chip Enable Output) of the first XC1701 drives the CE input of the next device, allowing seamless expansion.

  • Data Integrity: Built on a low-power CMOS Floating Gate Process, providing non-volatile storage without the need for battery backup.

Figure 2: Internal block diagram

2. Naming / Variant Map and Selection Guide

2.1 Part Number Decoding

The part numbering system for the XC1701 indicates voltage, package, and temperature grade. 

- Prefix: XC1701 (1 Mbit density). - Voltage Indicator: L indicates 3.3V operation. Absence of L indicates standard 5V operation. 

- Package: PC20 (PLCC-20), SO20 (SOIC-20). 

- Grade: C (Commercial, 0°C to +70°C), I (Industrial, -40°C to +85°C).

2.2 Core Variant Comparison

VariantVoltagePackageStatus
XC1701PC20C5V20-pin PLCCObsolete
XC1701SO20C5V20-pin SOICObsolete
XC1701LPC20C3.3V20-pin PLCCObsolete
XC1701LSO20C3.3V20-pin SOICObsolete

3. Key Specifications Explained

Values listed are based on standard operating conditions. Refer to the specific historical datasheet for absolute maximum ratings.

3.1 Power / Voltage / Operating Range

  • Memory Size: 1 Mbit (1,048,576 x 1 bit).

  • Standard Voltage: 4.75V to 5.25V (Nominal 5V).

  • Low Voltage ("L" Series): Optimized for 3.3V logic systems.

  • Quiescent Current: Low-power CMOS technology ensures minimal draw during standby, though specific microamp figures requires the datasheet.

3.2 Performance / Efficiency / Thermal

  • Clock Speed: The device supports the configuration clock speeds requisite for Spartan and Virtex series devices.

  • Programming Technology: One-Time Programmable (OTP). Efficiency in production is high due to non-volatility, but development efficiency is lower compared to ISP-capable flash devices.

4. Design Notes and Common Integration Issues

4.1 Reference Design Notes

  • Reset Polarity: Ensure the RESET/OE polarity matches the target FPGA's requirements. The XC1701 supports active-high and active-low reset configurations depending on the specific pin strapping.

  • Pull-up Resistors: The DATA line is an open-collector output (on some legacy variants) or push-pull; verify if a pull-up resistor is required on the DATA line to ensure clean logic highs during configuration.

4.2 Layout / EMI / Thermal Checklist

  • Decoupling: Place a 0.1µF ceramic capacitor and a 10µF tantalum capacitor as close as possible to the VCC and GND pins (Pin 20 and Pin 10 on PLCC) to mitigate switching noise during the serial clocking.

  • OTP Pain Point: Since the device is OTP, engineers must verify the bitstream entirely using a reprogrammable XC18V00 series or JTAG emulation before burning the XC1701. A single bit error renders the chip useless.

5. Typical Applications

The XC1701 is almost exclusively found in legacy hardware platforms.

Application Analysis

  • FPGA Configuration Storage: Primary boot memory for Xilinx Spartan-II and Virtex-E devices.

  • Embedded System Boot Code: Storing initialization routines for microcontrollers utilizing external serial boot modes.

  • Industrial Control Systems: Used in long-lifecycle logic controllers where non-volatility without battery backup was strictly required.

6. Competitors and Alternatives

Direct drop-in replacements are rare due to the proprietary nature of the pinout and obsolete package types. 

- Atmel (Microchip) AT17 Series: Functionally similar configuration EEPROMs, often pin-compatible with legacy Xilinx footprints. 

- STMicroelectronics M27 Series: Non-volatile memory alternatives, though often parallel rather than serial. 

- Modern Migration: For new designs or extensive repairs, engineers often design a small adapter board using a modern SPI Flash (e.g., Winbond) and a logic level shifter/serializer if the target FPGA supports SPI modes, alleviating the supply chain risk of the XC1701.

7. FAQ

Q: Can I reprogram the XC1701?A: No. The XC1701 is a One-Time Programmable (OTP) device. Once the fuse map is blown, it cannot be erased. For development, use re-programmable alternatives like the XC18V series.

Q: How do I program a blank XC1701?A: You require a device programmer capable of handling legacy Xilinx PROMs, such as the Xilinx HW-130 or universal programmers from Data I/O, BP Microsystems, or Xeltek. Modern JTAG cables often cannot program these standalone OTP chips directly in-circuit without specific legacy support.

Q: What is the difference between XC1701 and XC1701L?A: The XC1701 operates at 5V logic levels, while the XC1701L is designed for 3.3V systems. Using the incorrect voltage variant can damage the device or the connected FPGA.

Q: Is the XC1701 still in production?A: No, the series is Obsolete/End of Life.

Specifications

Xilinx Inc. XC1701SO20C technical specifications, attributes, parameters and parts with similar specifications to Xilinx Inc. XC1701SO20C.
  • Type
    Parameter
  • Mounting Type

    The "Mounting Type" in electronic components refers to the method used to attach or connect a component to a circuit board or other substrate, such as through-hole, surface-mount, or panel mount.

    Surface Mount
  • Package / Case

    refers to the protective housing that encases an electronic component, providing mechanical support, electrical connections, and thermal management.

    20-SOIC (0.295, 7.50mm Width)
  • Surface Mount

    having leads that are designed to be soldered on the side of a circuit board that the body of the component is mounted on.

    YES
  • Number of Pins
    20
  • Operating Temperature

    The operating temperature is the range of ambient temperature within which a power supply, or any other electrical equipment, operate in. This ranges from a minimum operating temperature, to a peak or maximum operating temperature, outside which, the power supply may fail.

    0°C~70°C
  • Packaging

    Semiconductor package is a carrier / shell used to contain and cover one or more semiconductor components or integrated circuits. The material of the shell can be metal, plastic, glass or ceramic.

    Tube
  • Published
    2000
  • JESD-609 Code

    The "JESD-609 Code" in electronic components refers to a standardized marking code that indicates the lead-free solder composition and finish of electronic components for compliance with environmental regulations.

    e0
  • Pbfree Code

    The "Pbfree Code" parameter in electronic components refers to the code or marking used to indicate that the component is lead-free. Lead (Pb) is a toxic substance that has been widely used in electronic components for many years, but due to environmental concerns, there has been a shift towards lead-free alternatives. The Pbfree Code helps manufacturers and users easily identify components that do not contain lead, ensuring compliance with regulations and promoting environmentally friendly practices. It is important to pay attention to the Pbfree Code when selecting electronic components to ensure they meet the necessary requirements for lead-free applications.

    no
  • Part Status

    Parts can have many statuses as they progress through the configuration, analysis, review, and approval stages.

    Obsolete
  • Moisture Sensitivity Level (MSL)

    Moisture Sensitivity Level (MSL) is a standardized rating that indicates the susceptibility of electronic components, particularly semiconductors, to moisture-induced damage during storage and the soldering process, defining the allowable exposure time to ambient conditions before they require special handling or baking to prevent failures

    1 (Unlimited)
  • Number of Terminations
    20
  • ECCN Code

    An ECCN (Export Control Classification Number) is an alphanumeric code used by the U.S. Bureau of Industry and Security to identify and categorize electronic components and other dual-use items that may require an export license based on their technical characteristics and potential for military use.

    EAR99
  • Terminal Finish

    Terminal Finish refers to the surface treatment applied to the terminals or leads of electronic components to enhance their performance and longevity. It can improve solderability, corrosion resistance, and overall reliability of the connection in electronic assemblies. Common finishes include nickel, gold, and tin, each possessing distinct properties suitable for various applications. The choice of terminal finish can significantly impact the durability and effectiveness of electronic devices.

    Tin/Lead (Sn85Pb15)
  • Additional Feature

    Any Feature, including a modified Existing Feature, that is not an Existing Feature.

    USED FOR STORING THE CONFIGURATION BITSTREAMS OF XILINX FPGAS
  • HTS Code

    HTS (Harmonized Tariff Schedule) codes are product classification codes between 8-1 digits. The first six digits are an HS code, and the countries of import assign the subsequent digits to provide additional classification. U.S. HTS codes are 1 digits and are administered by the U.S. International Trade Commission.

    8542.32.00.61
  • Voltage - Supply

    Voltage - Supply refers to the range of voltage levels that an electronic component or circuit is designed to operate with. It indicates the minimum and maximum supply voltage that can be applied for the device to function properly. Providing supply voltages outside this range can lead to malfunction, damage, or reduced performance. This parameter is critical for ensuring compatibility between different components in a circuit.

    4.75V~5.25V
  • Terminal Position

    In electronic components, the term "Terminal Position" refers to the physical location of the connection points on the component where external electrical connections can be made. These connection points, known as terminals, are typically used to attach wires, leads, or other components to the main body of the electronic component. The terminal position is important for ensuring proper connectivity and functionality of the component within a circuit. It is often specified in technical datasheets or component specifications to help designers and engineers understand how to properly integrate the component into their circuit designs.

    DUAL
  • Terminal Form

    Occurring at or forming the end of a series, succession, or the like; closing; concluding.

    GULL WING
  • Peak Reflow Temperature (Cel)

    Peak Reflow Temperature (Cel) is a parameter that specifies the maximum temperature at which an electronic component can be exposed during the reflow soldering process. Reflow soldering is a common method used to attach electronic components to a circuit board. The Peak Reflow Temperature is crucial because it ensures that the component is not damaged or degraded during the soldering process. Exceeding the specified Peak Reflow Temperature can lead to issues such as component failure, reduced performance, or even permanent damage to the component. It is important for manufacturers and assemblers to adhere to the recommended Peak Reflow Temperature to ensure the reliability and functionality of the electronic components.

    225
  • Number of Functions
    1
  • Supply Voltage

    Supply voltage refers to the electrical potential difference provided to an electronic component or circuit. It is crucial for the proper operation of devices, as it powers their functions and determines performance characteristics. The supply voltage must be within specified limits to ensure reliability and prevent damage to components. Different electronic devices have specific supply voltage requirements, which can vary widely depending on their design and intended application.

    5V
  • Terminal Pitch

    The center distance from one pole to the next.

    1.27mm
  • Time@Peak Reflow Temperature-Max (s)

    Time@Peak Reflow Temperature-Max (s) refers to the maximum duration that an electronic component can be exposed to the peak reflow temperature during the soldering process, which is crucial for ensuring reliable solder joint formation without damaging the component.

    30
  • Base Part Number

    The "Base Part Number" (BPN) in electronic components serves a similar purpose to the "Base Product Number." It refers to the primary identifier for a component that captures the essential characteristics shared by a group of similar components. The BPN provides a fundamental way to reference a family or series of components without specifying all the variations and specific details.

    XC1701
  • Pin Count

    a count of all of the component leads (or pins)

    20
  • Operating Supply Voltage

    The voltage level by which an electrical system is designated and to which certain operating characteristics of the system are related.

    5V
  • Power Supplies

    an electronic circuit that converts the voltage of an alternating current (AC) into a direct current (DC) voltage.?

    5V
  • Programmable Type

    These include Field Programmable Logic Devices (FPGAs), Complex Programmable Logic Devices (CPLD) and Programmable Logic Devices (PLD, PLA, PAL, GAL). There are also devices that are the analog equivalent of these called field programmable analog arrays.

    OTP
  • Clock Frequency

    Clock frequency, also known as clock speed, refers to the rate at which a processor or electronic component can execute instructions. It is measured in hertz (Hz) and represents the number of cycles per second that the component can perform. A higher clock frequency typically indicates a faster processing speed and better performance. However, it is important to note that other factors such as architecture, efficiency, and workload also play a significant role in determining the overall performance of a component. In summary, clock frequency is a crucial parameter that influences the speed and efficiency of electronic components in processing data and executing tasks.

    15MHz
  • Organization

    In the context of electronic components, the parameter "Organization" typically refers to the arrangement or structure of the internal components within a device or system. It can describe how various elements such as transistors, resistors, capacitors, and other components are physically arranged and interconnected on a circuit board or within a semiconductor chip.The organization of electronic components plays a crucial role in determining the functionality, performance, and efficiency of a device. It can impact factors such as signal propagation, power consumption, thermal management, and overall system complexity. Engineers carefully design the organization of components to optimize the operation of electronic devices and ensure reliable performance.Different types of electronic components may have specific organizational requirements based on the intended application and design considerations. For example, integrated circuits may have a highly compact and intricate organization to maximize functionality within a small footprint, while larger electronic systems may have a more modular and distributed organization to facilitate maintenance and scalability.

    1MX1
  • Output Characteristics

    Output characteristics in electronic components refer to the relationship between the output voltage and output current across a range of input conditions. This parameter is essential for understanding how a device, such as a transistor or operational amplifier, behaves under various loads and operating points. It provides insights into the efficiency, performance, and limitations of the component, helping designers to make informed choices for circuits and applications.

    3-STATE
  • Memory Width

    Memory width refers to the number of bits that can be read or written to memory at one time. It is an important specification in electronic components, particularly in memory devices like RAM and cache. A wider memory width allows for greater data throughput, enabling faster performance as more data can be processed simultaneously. Memory width can vary among different types of memory and can impact both the complexity and efficiency of data handling within electronic systems.

    1
  • Density

    In electronic components, "Density" refers to the mass or weight of a material per unit volume. It is a physical property that indicates how tightly packed the atoms or molecules are within the material. The density of a component can affect its performance and characteristics, such as its strength, thermal conductivity, and electrical properties. Understanding the density of electronic components is important for designing and manufacturing processes to ensure optimal performance and reliability.

    1 Mb
  • Standby Current-Max

    Standby Current-Max refers to the maximum amount of current that an electronic component or device consumes while in a low-power standby mode. This parameter is critical for power management, especially in battery-operated devices, as it indicates how efficiently the device can conserve energy when not actively in use. A lower Standby Current-Max value is typically desirable, as it contributes to longer battery life and reduced energy consumption. Manufacturers specify this value to help engineers select components that meet specific power efficiency requirements in their designs.

    0.00005A
  • Parallel/Serial

    The parameter "Parallel/Serial" in electronic components refers to the method of data transmission or communication within the component. In parallel communication, multiple bits of data are transmitted simultaneously over multiple channels or wires. This allows for faster data transfer rates but requires more physical connections and can be more susceptible to signal interference.On the other hand, in serial communication, data is transmitted sequentially over a single channel or wire. While serial communication may have slower data transfer rates compared to parallel communication, it is more cost-effective, requires fewer connections, and is less prone to signal interference.The choice between parallel and serial communication depends on the specific requirements of the electronic component and the overall system design, balancing factors such as speed, cost, complexity, and reliability.

    SERIAL
  • I/O Type

    "I/O Type" in electronic components refers to the type of input/output interface that the component uses to communicate with other devices or systems. This parameter specifies whether the component uses analog or digital signals for input and output operations. Analog signals are continuous and can have an infinite number of values, while digital signals are discrete and have only two possible values (0 or 1).Understanding the I/O Type of an electronic component is crucial for ensuring compatibility and proper communication with other components in a circuit or system. It helps determine the type of signals that the component can send and receive, as well as the protocols and standards that need to be followed for successful data exchange.In summary, the I/O Type parameter of electronic components defines the nature of the signals used for input and output operations, whether they are analog or digital, and plays a key role in establishing seamless communication within electronic systems.

    COMMON
  • Memory IC Type

    Memory IC Type refers to the specific type of integrated circuit (IC) used for storing data in electronic devices. Memory ICs are essential components in computers, smartphones, and other digital devices, as they provide temporary or permanent storage for data and instructions. Common types of memory ICs include dynamic random-access memory (DRAM), static random-access memory (SRAM), flash memory, and electrically erasable programmable read-only memory (EEPROM). Each type of memory IC has unique characteristics in terms of speed, capacity, power consumption, and data retention, making it suitable for different applications. Understanding the memory IC type is crucial for designing and selecting the appropriate memory solution for a specific electronic device or system.

    CONFIGURATION MEMORY
  • Length
    12.827mm
  • Height Seated (Max)

    Height Seated (Max) is a parameter in electronic components that refers to the maximum allowable height of the component when it is properly seated or installed on a circuit board or within an enclosure. This specification is crucial for ensuring proper fit and alignment within the overall system design. Exceeding the maximum seated height can lead to mechanical interference, electrical shorts, or other issues that may impact the performance and reliability of the electronic device. Manufacturers provide this information to help designers and engineers select components that will fit within the designated space and function correctly in the intended application.

    2.6416mm
  • Width
    7.5184mm
  • Radiation Hardening

    Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation, especially for environments in outer space (especially beyond the low Earth orbit), around nuclear reactors and particle accelerators, or during nuclear accidents or nuclear warfare.

    No
  • RoHS Status

    RoHS means “Restriction of Certain Hazardous Substances” in the “Hazardous Substances Directive” in electrical and electronic equipment.

    Non-RoHS Compliant
  • Lead Free

    Lead Free is a term used to describe electronic components that do not contain lead as part of their composition. Lead is a toxic material that can have harmful effects on human health and the environment, so the electronics industry has been moving towards lead-free components to reduce these risks. Lead-free components are typically made using alternative materials such as silver, copper, and tin. Manufacturers must comply with regulations such as the Restriction of Hazardous Substances (RoHS) directive to ensure that their products are lead-free and environmentally friendly.

    Contains Lead
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Datasheet PDF

Download datasheets and manufacturer documentation for Xilinx Inc. XC1701SO20C.
XC1701SO20C

Xilinx Inc.

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