Serial Number iButton

General Description

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 single data lead and a ground return. Every DS1990A is factory lasered with a guaranteed unique 64-bit registration number that allows for absolute traceability. The durable stainless-steel iButton package is highly resistant to environmental hazards such as dirt, moisture, and shock. Its compact coin-shaped profile is selfaligning 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

• Access Control
• Work-In-Progress Tracking
• Tool Management
• Inventory Control

Ordering Information

+Denotes a lead-free/RoHS-compliant package.

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

♦ Easily Affixed with Self-Stick Adhesive Backing, Latched by its Flange, or Locked with a Ring Pressed Onto its Rim

ABSOLUTE MAXIMUM RATINGS

IO Voltage Range to GND.....................................-0.5V to +6.0V

IO Sink Current....................................................................20mA

Junction Temperature......................................................+125°C

Storage Temperature Range .............................-55°C to +125°C

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Pin Configurations

Detailed Description

The block diagram in Figure 1 shows the major function blocks of the device. The DS1990A takes the energy it needs to operate from the IO line, as indicated by the parasite power block. The ROM function control unit includes the 1-Wire interface and the logic to implement the ROM function commands, which access 64 bits of lasered ROM.

Block Diagram