Analog Devices Inc./Maxim Integrated DS2502S+T&R

Overview

DS2502S+T&R from Maxim Integrated is a 1-Wire add-only memory IC with factory-lasered 64-bit ROM ID, 1024-bit EPROM (4 × 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 maintenance records in industrial sensors and medical devices.

For engineers reviewing the DS2502S+T&R datasheet, DS2502S+T&R pinout, DS2502S+T&R application, or DS2502S+T&R equivalent, this device requires 12V programming pulses, supports 16.3kbps 1-Wire communication, operates from 2.8V–6.0V at –40°C to +85°C, and uses an 8-pin SOIC package with DATA and GND pins only - no V_DD supply needed.

Technical Context

The DS2502S+T&R implements a hierarchical 1-Wire protocol: ROM function commands (Read/Match/Search/Skip ROM) must precede memory access. Its internal architecture includes a 64-bit lasered ROM (8-bit family code 09h, 48-bit serial number, 8-bit CRC), 1024-bit EPROM partitioned into four 32-byte pages, and 64-bit status memory with write-protect and page-redirection bytes.

Programming requires precise 12.0V ±0.5V pulses of 480µs duration applied to the DATA line; read operations draw power parasitically from the 1-Wire bus. Data integrity is enforced via on-the-fly 8-bit CRC generation per command and per-page during Read Data/Generate 8-Bit CRC mode, with all bit transfers LSB-first.

Key Specifications

Pinout & Package

DS2502S+T&R is housed in an 8-pin SOIC (150 mil) surface-mount package. Only two terminals are functional: Pin 1 (DATA) handles bidirectional 1-Wire communication and programming voltage injection; Pin 2 (GND) provides ground reference. Pins 3–8 are No Connect (NC).

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 DS2502S+T&R uniquely combines guaranteed unique ROM ID, 12V-programmable EPROM, parasitic power, and page redirection - making it irreplaceable for legacy 1-Wire systems requiring immutable, low-pin-count traceability without external power or crypto overhead.

Availability

DS2502S+T&R is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device UDI compliance, and embedded asset tracking requiring stable component supply across long product lifecycles.

Supply support for DS2502S+T&R 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

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and digital ICs for industrial, automotive, and communications markets.

The DS2502S+T&R belongs to Maxim's 1-Wire memory family, engineered specifically for low-pin-count, parasitically powered traceability in harsh environments - prioritizing uniqueness, immutability, and minimal system integration overhead.

FAQ

What is the function of the 64-bit ROM in DS2502S+T&R?

The 64-bit ROM in DS2502S+T&R contains a factory-lasered, guaranteed unique identifier comprising an 8-bit family code (09h), 48-bit serial number, and 8-bit CRC. This ROM enables absolute device-level traceability and is used during 1-Wire bus enumeration (via Read ROM, Match ROM, or Search ROM commands) before accessing the EPROM. The DS2502S+T&R relies on this ROM for singulation in multidrop networks and cannot operate without successful ROM command execution.

Can DS2502S+T&R be reprogrammed after initial write?

Yes - but only in add-only mode: bits can change from 1 to 0, never 0 to 1. New data is appended by programming unused bits within existing pages or redirecting to new pages using EPROM Status Bytes. Once a page is write-protected via its status bit, it becomes permanently read-only. The DS2502S+T&R does not support bulk erase; its architecture assumes incremental, irreversible updates - a core design feature for audit-log and calibration applications.

What voltage is required to program DS2502S+T&R?

DS2502S+T&R requires a precisely controlled 11.5V to 12.0V programming pulse (±0.5V tolerance) applied to the DATA pin for 480µs. This high-voltage pulse is generated externally by the 1-Wire master - the DS2502S+T&R itself detects this condition internally to enable EPROM programming. Programming is only valid between –40°C and +50°C; outside this range, the DS2502S+T&R will reject programming attempts.

Does DS2502S+T&R require an external power supply?

No - DS2502S+T&R operates entirely on parasitic power harvested from the 1-Wire bus during high-voltage periods, eliminating the need for V_DD. During read operations (2.8V–6.0V), it stores charge on an internal capacitor to sustain operation through low-bus phases. However, programming still requires the external 12V pulse on the DATA line - no separate V_DD pin exists, and pins 3–8 are NC. This makes the DS2502S+T&R ideal for space-constrained, low-pin-count designs.

How does page redirection work in DS2502S+T&R?

DS2502S+T&R implements page redirection via four dedicated Page Address Redirection Bytes in its EPROM Status Memory. Each byte corresponds to one of the four 256-bit pages. Writing the one's complement of a new page address (e.g., FDh for page 2) into a redirection byte invalidates the original page and redirects reads to the target page. The DS2502S+T&R hardware does not interpret these bytes - redirection is handled entirely in host firmware, enabling software-based "patching" of stored data without physical reprogramming.