TM1990A iButton Master Access Control Card Readers

Description

TM1990A iButton Master Access Control Card Readers The TM1990A is a CMOS electronic key device that contains a unique 64-bit digital code stored in internal nonvolatile memory. Communication with the device is performed through the 1-Wire protocol, requiring only a DATA line and a common GND connection. The device supports ROM search functionality, allowing multiple TM1990A devices to share the same 1-Wire bus. During operation, a master controller initializes the 1-Wire bus and communicates with the TM1990A using ROM function commands. The device can provide its group code, unique 48-bit serial number, and 8-bit CRC, making it suitable for electronic identification and access-control applications. Features: Unique electronic identification. Nonvolatile internal memory. 1-Wire communication interface. Requires only one data connection and common ground. Supports ROM search on a shared 1-Wire bus. Contact-based electronic key operation. Compatible with DS1990-type identification systems. Compact iButton form factor. Suitable for master-controlled identification systems. Specifications: Parameter Specification Device Type CMOS electronic key Identification Code 64-bit Serial Number 48-bit Group Code 8-bit CRC 8-bit Communication Protocol 1-Wire Data Lines 1 data line + GND Memory Type Nonvolatile ROM Read Commands 33h / 0Fh ROM Search Command F0h Operating Voltage / Pull-Up 2.8–6.0 V Logic High Input 2.2 V to Vpup + 0.3 V Logic Low Input -0.3 V to +0.8 V Low-Level Output Voltage Max. 0.4 V at 4 mA Operating Temperature -40°C to +85°C Storage Temperature -55°C to +125°C Voltage at Pins Relative to GND -0.5 to +7.0 V Contact Type Electronic key / iButton contact Applications: Access-control systems. Electronic door locks. Electronic key systems. User identification Equipment identification. Security systems. Attendance systems. Industrial access systems. Embedded identification systems. Multi-device 1-Wire identification networks. Package Includes: 1x TM1990A iButton Master Access Control Card Readers. Documents: TM1990A Datasheet.

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