DS2431X-S+ is a 1024-bit, 1-Wire® EEPROM memory device designed and manufactured by Analog Devices Inc. (ADI) — formerly Maxim Integrated (acquired by ADI in 2021). It belongs to the robust, low-power DS2431 family, engineered specifically for electronic identification, calibration data storage, sensor configuration, and secure traceability applications, where contactless, single-conductor (1-Wire) communication, tamper-resistant memory, and guaranteed data retention are essential.
The “X-S+” suffix denotes the TSOC-6 package (3.7 mm × 4.0 mm × 1.5 mm) — a compact, surface-mount, RoHS-compliant, and industry-standard package optimized for automated assembly; qualified for industrial temperature range (–40°C to +85°C ambient).
â ī¸ Critical Clarification:
The DS2431X-S+ is not a standard I²C or SPI EEPROM. It is a parasitically powered, 1-Wire interface EEPROM, featuring:
- 1024 bits (128 bytes) of nonvolatile EEPROM memory, organized into four 256-bit pages (32 bytes each), with individual page write protection and 1-wire addressable uniqueness;
- Globally unique 64-bit ROM ID: Factory-laser-trimmed serial number (e.g.,
2D 00 00 00 9A 4F 1E 2B) — enables true device-level identification and eliminates need for external addressing logic;
- Parasitic power operation: Draws power directly from the 1-Wire bus during communication — no VDD supply required (though optional VDD pin supports strong-pullup mode for faster writes);
- High reliability & security: > 50,000 write/erase cycles per page, > 10-year data retention at +85°C, and hardware write-protection (per-page or global) — preventing accidental or malicious overwrites;
- Robust 1-Wire protocol: Supports standard 1-Wire commands (Search ROM, Read ROM, Match ROM, Skip ROM, Read Memory, Write Memory, Copy Memory, Recall Memory, Read Status), with built-in CRC-16 error checking for all data transfers.
It operates over a wide voltage range (2.8 V to 5.25 V), communicates at up to 15.4 kbps (standard speed) or 125 kbps (overdrive mode), and features low active current (< 5 µA standby, < 5 mA during write) — making it ideal for battery-free or energy-harvesting systems.
Introduction
The DS2431X-S+ delivers industrial-grade traceability and configurability in the simplest possible form factor:
đš True plug-and-play identification: Each unit ships with a globally unique 64-bit ROM ID — enabling automatic inventory management, firmware binding, and anti-counterfeiting without host-side database coordination;
đš Zero-power memory for harsh environments: Parasitic operation allows embedding directly into sensors, probes, cables, or consumables (e.g., medical cartridges, printer ink tanks) — no battery, no wiring complexity, no risk of power failure corrupting calibration data;
đš Tamper-evident calibration storage: Page-level write protection ensures factory calibration coefficients remain immutable while allowing field-updatable parameters (e.g., sensor offset, linearization tables) in unprotected pages;
đš Production-ready robustness: Pre-qualified across HTOL (1000 h @ 125°C), with FIT rate < 8 failures per billion hours, and qualification per JEDEC JESD22-A108 and MIL-STD-883 — suitable for 15+ year deployments in infrastructure and medical devices.
Its 6-lead TSOC (X-S+) package (3.7 mm × 4.0 mm × 1.5 mm) offers excellent manufacturability, moisture resistance (MSL 1), and compatibility with reflow and wave-solder processes — making it a go-to solution for high-volume industrial, medical, and consumer applications requiring embedded intelligence.
Key Features
â
1-Wire EEPROM Memory:
• Total memory: 1024 bits (128 bytes), organized as four 256-bit (32-byte) pages;
• Write endurance: > 50,000 cycles per page;
• Data retention: > 10 years at +85°C, > 40 years at +25°C;
• Write time: ≤ 10 ms per page (with strong pullup), ≤ 20 ms (parasitic mode).
â
Unique Identity & Security:
• 64-bit laser-trimmed ROM ID: Composed of 8-bit family code (2Dh), 48-bit serial number, and 8-bit CRC — guarantees global uniqueness;
• Page write protection: Hardware lock bits per page (P0–P3); global write-disable via EPROM fuse;
• Tamper detection: No internal battery or capacitor — any physical intrusion permanently disrupts ROM ID integrity.
â
Parasitic & Flexible Power Operation:
• Power modes: Parasitic (VDD = GND) or externally powered (VDD connected);
• Supply voltage range: 2.8 V to 5.25 V;
• Active current: < 5 mA during write, < 5 µA standby;
• Strong-pullup support: Optional VDD pin enables faster writes and higher noise immunity.
â
Robust Communication & Diagnostics:
• Interface: Single-conductor 1-Wire bus, compliant with DS2480B/DS2482/DS9490R master ICs and microcontroller GPIO bit-banging;
• Speed modes: Standard (15.4 kbps) and Overdrive (125 kbps);
• Error detection: CRC-16 checksum on all memory reads/writes and ROM reads;
• Built-in status register: Reports power mode, page lock status, and copy status.
â
TSOC-6 (X-S+) Package & Industrial Qualification:
• 6-Lead TSOC (3.7 mm × 4.0 mm × 1.5 mm);
• RoHS-compliant, Pb-free, halogen-free;
• JEDEC J-STD-020 moisture sensitivity level (MSL) 1 — unlimited floor life;
• Operating ambient temperature: –40°C to +85°C.
Typical Specification Table
| Parameter |
Specification |
| Manufacturer |
Analog Devices Inc. (ADI) |
| Product Series |
DS2431 Family (1-Wire EEPROM) |
| Model |
DS2431X-S+ |
| Function |
1024-Bit 1-Wire EEPROM with Unique ID |
| Memory Size |
1024 bits (128 bytes), 4 × 256-bit pages |
| Write Endurance |
> 50,000 cycles per page |
| Data Retention |
> 10 years @ +85°C |
| Write Time (per page) |
≤ 10 ms (strong pullup), ≤ 20 ms (parasitic) |
| ROM ID |
64-bit unique (family code + serial + CRC) |
| Interface |
1-Wire (single conductor + ground) |
| Communication Speed |
Standard: 15.4 kbps; Overdrive: 125 kbps |
| Supply Voltage Range |
2.8 V to 5.25 V |
| Power Modes |
Parasitic (no VDD) or externally powered |
| Package |
6-Lead TSOC (3.7 mm × 4.0 mm × 1.5 mm) (X-S+) |
| RoHS / Green |
Yes (Pb-free, Halogen-free) |
| Operating Temp. Range |
–40°C to +85°C ambient |
Typical Applications
đš Sensor Calibration & Traceability: Storing factory calibration coefficients (gain, offset, linearity), NIST-traceable metadata, and sensor serial numbers in pressure transducers, RTD probes, and flow meters — enabling automatic calibration recall and audit compliance (ISO 17025, FDA 21 CFR Part 11).
đš Medical Device Consumables: Inkjet printer cartridges, dialysis fluid bags, infusion pump cassettes, and surgical instrument tags — using unique ID for usage tracking, anti-cloning, and expiration date enforcement.
đš Industrial Equipment Identification: Motor nameplates, transformer tags, HVAC control valves, and PLC I/O modules — enabling predictive maintenance logs, firmware version binding, and spare-part authenticity verification.
đš Battery-Free IoT Nodes: Embedded in energy-harvesting sensors (e.g., solar-powered soil moisture nodes), where parasitic power eliminates need for batteries or supercaps — storing node ID, deployment location, and last calibration timestamp.
đš Cable & Connector Authentication: High-reliability aerospace/military cables, fiber optic patch panels, and test equipment interconnects — preventing miswiring and ensuring signal integrity through hardware-enforced topology mapping.
đš Smart Packaging & Anti-Counterfeiting: Luxury goods, pharmaceuticals, and semiconductor wafers — leveraging unclonable ROM ID and write-protected memory to verify origin and detect tampering.
Development & Design Notes
đ§ PCB Layout Best Practices:
- Keep 1-Wire bus trace short and routed away from noisy signals (clocks, switching regulators) — use 100 Ω series termination resistor near master if bus length > 1 m;
- Place 4.7 kΩ pullup resistor between 1-Wire bus and VCC (or use DS2482’s internal pullup);
- For parasitic mode: ensure master supports strong-pullup timing — critical for reliable page writes.
đ§ 1-Wire Bus Design & Timing:
- Use standard-speed mode (15.4 kbps) for reliability over long cables (> 100 m); overdrive mode (125 kbps) only for short, noise-free PCB traces (< 10 cm);
- Implement CRC-16 validation on all reads/writes — prevents silent data corruption;
- Always perform “Recall Memory” command after power-up to reload EEPROM contents into SRAM latches before reading.
đ§ Write Protection & Data Integrity:
- Lock calibration pages (e.g., P0) during manufacturing using
Write Protection command — irreversible unless global EPROM fuse is blown (not recommended);
- Store critical metadata (date, operator ID, calibration standard) in unprotected pages (e.g., P3) for field updates;
- Use
Copy Memory command to atomically transfer updated values from SRAM to EEPROM — avoids partial writes during power loss.
đ§ Thermal Management & Reliability:
- TSOC-6 has excellent thermal performance (θJA ≈ 180°C/W). No heatsink needed — operates reliably in sealed enclosures up to +85°C.
- FIT rate = 7.6 failures per billion hours, validated over 1000 h HTOL — suitable for 20+ year deployments.
đ§ System-Level Integration Tips:
- Pair with 1-Wire master ICs like DS2482-100 (I²C-to-1-Wire bridge) or DS2482-800 (8-channel) for MCU-friendly integration;
- In multi-drop buses: use
Search ROM to auto-discover and enumerate all DS2431s — enables scalable sensor networks without manual addressing;
- For security-critical apps: combine ROM ID with HMAC-SHA256 challenge-response on host side — adds cryptographic authentication beyond hardware uniqueness.
