Analog Devices Inc./Maxim Integrated DS2502P+

Overview

DS2502P+ 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 and embedded systems.

For engineers reviewing the DS2502P+ datasheet, DS2502P+ pinout, DS2502P+ application, or DS2502P+ equivalent, key selection considerations include 1-Wire interface compatibility, TSOC-6 package footprint, -40°C to +85°C operating range, 12V programming voltage requirement, and page redirection capability for data patching without physical rework.

Technical Context

The DS2502P+ implements a hierarchical 1-Wire protocol requiring ROM function commands (e.g., Read ROM, Skip ROM) before accessing EPROM via memory function commands (e.g., Read Memory [F0h], Write Memory [0Fh]). Its internal architecture includes an 8-bit scratchpad buffer, 8-bit CRC generator, and program voltage detect circuit that enables 12V pulse-triggered bit programming.

EPROM bits transition only from 1→0; no 0→1 reversal is possible. Page Address Redirection Bytes (in Status Memory) allow software to logically invalidate a page and redirect reads to another page using one's complement addressing-enabling firmware-level data updates without hardware replacement.

Key Specifications

Pinout & Package

DS2502P+ uses the TSOC-6 surface-mount package: compact, RoHS-compliant, qualified for automated PCB assembly. Pin 1 = DATA (1-Wire I/O), Pin 2 = GND, Pins 3–6 = NC (no connection).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 1-Wire add-only memory applications.

Compared with DS2502P+, DS2430A+ offers rewrite flexibility but sacrifices data immutability and patching logic; DS28EC20 adds cryptographic assurance and capacity but requires external power and increases system overhead - DS2502P+ remains optimal for cost-sensitive, tamper-evident traceability with field-updatable logic.

Availability

DS2502P+ is available at Aetrix Electronics and suitable for industrial calibration systems, asset tracking deployments, and product revision management requiring stable component supply across extended production lifecycles.

Supply support for DS2502P+ 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 applications.

The DS2502P+ belongs to Maxim's 1-Wire memory family, engineered specifically for low-pin-count, parasitic-powered identification and immutable data logging in resource-constrained environments.

FAQ

What is the function of the DS2502P+ in a 1-Wire system?

The DS2502P+ functions as a slave device on a 1-Wire bus, providing guaranteed-unique identification via its factory-lasered 64-bit ROM and storing up to 1024 bits of user-programmable, add-only EPROM data. It derives operating power parasitically from the 1-Wire line during read operations and accepts 12V programming pulses for bit-level writes. The DS2502P+ supports page-level write protection and software-driven page redirection - making it ideal for calibration storage, asset tagging, and revision tracking where data immutability and field update capability are both required.

Does the DS2502P+ require an external power supply?

No, the DS2502P+ operates with parasitic power during read operations - drawing energy from the 1-Wire line through an internal capacitor. Only during programming does it require a 12V pulse applied to the same DATA line; no separate V_DD pin or external supply is needed. This eliminates the need for additional power routing on PCBs and reduces system component count. The DS2502P+ is fully functional in this single-wire configuration across its rated -40°C to +85°C temperature range.

How does page redirection work in the DS2502P+?

Page redirection in the DS2502P+ is implemented via four Page Address Redirection Bytes in its EPROM Status Memory. When a redirection byte contains a value other than FFh, the DS2502P+ interprets it as indicating that the corresponding main memory page is invalid, and the valid data resides at the one's complement of that value's page address. For example, FDh in the Page 1 redirection byte directs reads to Page 2. This mechanism allows software to "patch" data by invalidating an old page and writing updated content to a new page - all without altering the physical device. The DS2502P+ itself does not enforce or interpret redirection; it is purely a software-managed logical layer.

Can the DS2502P+ be reprogrammed multiple times?

Yes, the DS2502P+ supports multiple programming cycles - but only in add-only mode: bits can transition from 1→0 repeatedly, never from 0→1. Each write operation appends new data or updates status bytes without disturbing existing 0-bits. Pages can be individually write-protected after programming to prevent further changes. Because of this architecture, the DS2502P+ is suited for sequential logging (e.g., maintenance timestamps) and versioned data storage (via page redirection), but not for general-purpose rewritable memory. Reprogramming always requires a 12V pulse on the DATA line and strict adherence to the 1-Wire timing protocol.

What package type does the DS2502P+ use, and are there pin-compatible alternatives?

The DS2502P+ uses the TSOC-6 (Thin Small Outline Package, 6-pin) with Pin 1 = DATA and Pin 2 = GND; Pins 3–6 are NC. It is RoHS-compliant and qualified for standard SMT assembly. While other DS2502 variants exist in TO-92, SOT-23, SO, SFN, and WLP packages, none share identical pinout or footprint with the DS2502P+. Substituting another variant requires PCB layout revision due to differing pin counts, assignments, and mechanical dimensions. The DS2502P+ is uniquely specified for TSOC-6 - no pin-to-pin drop-in replacements exist within the DS2502 family or across competing 1-Wire memory ICs.