Analog Devices Inc./Maxim Integrated DS2502X1+U

Overview

DS2502X1+U from Maxim Integrated (now Analog Devices) is a 1-Wire add-only memory IC with factory-lasered 64-bit ROM ID, 1024-bit EPROM partitioned into four 256-bit pages, page-level write protection, and parasitic power operation. It serves as a tamper-resistant traceability tag for calibration data, asset tracking, and revision history in industrial sensors and medical devices.

For engineers reviewing the DS2502X1+U datasheet, DS2502X1+U pinout, DS2502X1+U application, or DS2502X1+U equivalent, this device requires 12V programming pulses, supports 1-Wire multidrop networks up to 16.3kbps, operates from 2.8V–6.0V at -40°C to +85°C, and uses only one microcontroller I/O pin for full read/write/control - making it ideal for space-constrained, low-pin-count embedded authentication systems.

Technical Context

The DS2502X1+U implements a hierarchical 1-Wire protocol: ROM function commands (Read/Match/Search/Skip ROM) must precede memory operations, enabling device singulation on shared buses. Its internal architecture includes an 8-bit scratchpad buffer, hardware CRC generator (X⁸+X⁵+X⁴+1), and parasitic power capacitor management.

EPROM programming follows strict bit-wise constraints: bits transition only from 1→0 (not 0→1); each byte is verified post-programming via LSB-first readback; page redirection is implemented via status bytes storing one's-complement page addresses. The WLP package has two terminals: DATA and GND - no V_DD pin required.

Key Specifications

Pinout & Package

DS2502X1+U uses a 4-terminal Wafer-Level Package (WLP), optimized for ultra-compact PCB footprints and direct electro-mechanical contact mounting. No soldering is required; terminals are accessed via compliant probe or spring-pin interface.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar add-only memory applications.

Compared with DS2430A+ and DS28EC20, the DS2502X1+U delivers the smallest form factor (WLP), lowest system-level pin count (1-wire), and strongest immutability guarantee for calibration and asset tagging - at the trade-off of no byte-erase capability and absence of crypto acceleration.

Availability

DS2502X1+U is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device traceability, and embedded asset tracking requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle support.

Supply support for DS2502X1+U 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

Analog Devices (via acquisition of Maxim Integrated) designs precision analog, mixed-signal, and digital ICs for industrial, automotive, and communications markets - with emphasis on reliability, low power, and system-level integration.

The DS2502X1+U belongs to Maxim's legacy 1-Wire memory family, engineered specifically for secure, low-pin-count device identification and immutable data storage in harsh environments - not general-purpose memory.

FAQ

What is the primary function of the DS2502X1+U in an embedded system?

The DS2502X1+U functions as a secure, single-pin 1-Wire add-only memory for storing immutable device identity and application-specific data such as calibration constants, asset IDs, or firmware revision logs. Its factory-lasered 64-bit ROM ID ensures absolute traceability, while its EPROM architecture guarantees data persistence without external power - making DS2502X1+U ideal for maintenance-free, long-life deployments in industrial and medical systems.

Does the DS2502X1+U require an external power supply?

No, the DS2502X1+U operates in parasitic power mode - deriving all operating energy from the 1-Wire data line during communication. It needs only a single I/O pin and pullup resistor; no V_DD connection is required. However, programming demands a transient 12V pulse on the same line, generated externally by the host controller - confirming DS2502X1+U's true single-wire, zero-quiescent-power design.

How does page redirection work in the DS2502X1+U?

Page redirection in DS2502X1+U is implemented via EPROM Status Bytes: each page has a corresponding redirection byte storing the one's-complement of a replacement page address. If the byte holds FDh, the valid data for Page 1 resides in Page 2. This lets firmware "patch" outdated data without overwriting - a core capability of DS2502X1+U's add-only architecture. The hardware does not auto-redirect; software must interpret these bytes during reads.

Can the DS2502X1+U be reprogrammed multiple times?

Yes, but only in additive mode: bits can transition from 1→0 repeatedly, never 0→1. New data is appended or superseded via page redirection - not overwritten. Each programming cycle requires a 12V pulse and CRC-verified write sequence. Because DS2502X1+U lacks erase capability, its lifetime is defined by total programmable bit transitions, not cycles - making DS2502X1+U optimal for infrequent, mission-critical updates like calibration or service logs.

What package type does the DS2502X1+U use, and how is it mounted?

The DS2502X1+U uses a 4-terminal Wafer-Level Package (WLP), measuring approximately 1.3mm × 1.3mm. It is designed for electro-mechanical contact mounting - not soldering - using compliant probes or spring-pin interfaces. Pins 1A/1B serve as the bidirectional DATA terminal; 2A/2B are GND. This ultra-compact, leadless form factor makes DS2502X1+U suitable for space-constrained modules where traditional SOIC or TO-92 packages are impractical.