The DS1990A serial number iButton® is a rugged data carrier that serves as an electronic registration number for automatic identification. Data is transferred serially through the 1-Wire® protocol, which requires only a sin- gle data lead and a ground return. Every DS1990A is factory lasered with a guaranteed unique 64-bit regis- tration number that allows for absolute traceability. The durable stainless-steel iButton package is highly resis- tant to environmental hazards such as dirt, moisture, and shock. Its compact coin-shaped profile is self- aligning with mating receptacles, allowing the DS1990A to be used easily by human operators. Accessories enable the DS1990A iButton to be mounted on almost any object, including containers, pallets, and bags. Applications include Access Control, Work-In-Progress Tracking, Tool Management, and Inventory Control. Features: Can Be Read in Less Than 5ms; Operating Range: 2.8V to 6.0V, -40°C to +85°C. Common iButton Features: Unique Factory-Lasered 64-Bit Registration Number Ensures Error-Free Device Selection and Absolute Traceability Because No Two Parts are Alike; Built-In Multidrop Controller for 1-Wire Net; Digital Identification by Momentary Contact; Data Can Be Accessed While Affixed to Object; Economically Communicates to Bus Master with a Single Digital Signal at 16.3kbps; Button Shape is Self-Aligning with Cup-Shaped Probes; Durable Stainless-Steel Case Engraved with Registration Number Withstands Harsh Environments.
The DS1990A iButton is a rugged stainless‑steel serial number device that stores a factory‑etched unique 64‑bit registration number. It communicates over a single‑wire (1‑Wire) bus, requiring only one signal line and ground, and is suitable for access control, workflow tracking, tool, and inventory management.
The manual provides physical dimensions, electrical characteristics, 1‑Wire bus architecture, ROM command set, and timing diagrams needed for integration with microcontrollers or 1‑Wire master chips such as the DS2480B. This manual is written in Chinese.
| Weight | ≈ 2.5 g |
|---|---|
| Operating Voltage | 2.8 V – 6.0 V |
| Storage Temperature | -55 °C – +125 °C |
| IO to GND Voltage Range | -0.5 V – +6.0 V |
| IO Sink Current | 20 mA |
| Maximum Data Rate | 16.3 kbps |
Each DS1990A includes a factory‑etched unique 64‑bit registration number.
The device can transmit data at up to 16.3 kbps.
It operates from 2.8 V to 6.0 V.
The iButton weighs about 2.5 grams.