Analog Devices Inc./Maxim Integrated DS2502S+

Overview

DS2502S+ 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 DS2502S+ datasheet, DS2502S+ pinout, DS2502S+ application, or DS2502S+ 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 SO package with DATA and GND terminals only - no V_DD supply needed.

Technical Context

The DS2502S+ implements a hierarchical 1-Wire protocol: ROM function commands (Read/Match/Search/Skip ROM) must precede memory operations. 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 8-byte status memory with write-protect and page-redirection control.

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 during Read Memory, Read Status, and Read Data/Generate CRC commands - all bit transfers occur LSB-first.

Key Specifications

Pinout & Package

DS2502S+ uses an 8-pin SOIC (150-mil) surface-mount package. Pins 1 and 2 are dedicated to DATA and GND respectively; pins 3–8 are no-connect (NC). Power is derived entirely from the 1-Wire DATA line - no V_DD or V_SS supply pins beyond GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS2502S+, DS2430A+ offers rewritable memory but loses 1-Wire compatibility and unique ID traceability, while DS28EC20 adds cryptographic security and larger capacity at higher cost and firmware complexity - DS2502S+ remains optimal for low-cost, tamper-evident, add-only identification in industrial maintenance and calibration use cases.

Availability

DS2502S+ is available at Aetrix Electronics and suitable for industrial calibration systems, asset tracking deployments, and maintenance record-keeping applications requiring stable component supply across extended product lifecycles.

Supply support for DS2502S+ 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 - emphasizing reliability, integration, and low-power operation.

The DS2502S+ belongs to Maxim's 1-Wire memory product line, engineered specifically for secure, low-pin-count identification and traceability in resource-constrained embedded systems - prioritizing simplicity, uniqueness, and field-updatable data integrity.

FAQ

What is the function of the 64-bit ROM ID in DS2502S+?

The 64-bit ROM ID in DS2502S+ consists of an 8-bit family code (09h), a 48-bit factory-lasered serial number, and an 8-bit CRC. It provides guaranteed unique device identification for absolute traceability across manufacturing lots and field deployments. This ID is used by the 1-Wire bus master during ROM Function Commands (e.g., Match ROM) to singulate and authenticate the DS2502S+ on a multidrop bus - no host-side ID generation or database lookup is required.

Can DS2502S+ be reprogrammed multiple times, and what are the limitations?

Yes, DS2502S+ supports multiple programming cycles, but only in add-only mode: bits transition from logical 1 to 0, never reversed. Each 256-bit page can be written incrementally, and page-level write protection can be permanently enabled after final programming. To update data, software uses Page Address Redirection Bytes to mark old pages invalid and map reads to newly programmed pages - enabling field patching without physical replacement of the DS2502S+.

What voltage and timing requirements apply to programming DS2502S+?

DS2502S+ requires a precisely timed 12.0V ±0.5V programming pulse of 480µs duration applied to the DATA line - no separate programming voltage rail is needed. The device must be within -40°C to +50°C during programming. Read operations function from 2.8V–6.0V at -40°C to +85°C with zero standby current. All 1-Wire communication, including CRC calculation and address handling, occurs LSB-first.

How does DS2502S+ achieve power autonomy without a V_DD pin?

DS2502S+ uses parasitic power: energy is harvested from the 1-Wire DATA line during high-voltage periods and stored on an internal capacitor, sustaining operation during low-voltage signal phases. This eliminates the need for a dedicated V_DD supply - only Pin 1 (DATA) and Pin 2 (GND) are electrically active. The design enables ultra-low-pin-count integration into space-constrained or cost-sensitive systems where board real estate and BOM count are critical.

Is DS2502S+ compatible with other 1-Wire devices on the same bus?

Yes, DS2502S+ includes a built-in multidrop controller and adheres strictly to the standard 1-Wire protocol hierarchy. It responds to ROM Function Commands (Read/Match/Search/Skip ROM) to coexist with other 1-Wire slaves like DS18B20 or DS2401 on the same bus. Its 8-bit family code (09h) ensures correct command routing, and presence-pulse acknowledgment confirms initialization - enabling scalable, mixed-node 1-Wire networks without protocol conflicts.