The DS1990A Serial Number iButton is a rugged data carrier that provides a unique 64‑bit registration number for automatic identification. It operates over a single 1‑Wire data line and is used in access control, inventory control, tool management and other applications. The device is housed in a stainless‑steel, coin‑shaped package that can be mounted on a wide range of objects.
The handbook details the physical and electrical specifications, the 1‑Wire bus system, hardware configuration, transaction sequences, and timing diagrams required for reliable communication. It also lists ordering information, accessories, and safety compliance.
| Operating Voltage Range | 2.8 V to 6.0 V |
|---|---|
| Operating Temperature Range | -40 °C to +85 °C |
| Weight | ≈ 2.5 g |
| Safety Standard | UL#913 (4th Edit.) |
Each DS1990A is factory‑lasered with a guaranteed unique 64‑bit registration number.
The device can be read in less than 5 ms.
It meets UL#913 (4th Edit.) and is approved for intrinsically safe use in hazardous locations.
The iButton weighs about 2.5 grams.