Analog Devices Inc./Maxim Integrated

The DS9490B is a USB bridge and holder for a single F5-size iButton®. The iButton is securely held behind a latched door. The DS9490R is a USB bridge with 1-Wire®RJ11 interface to accommodate 1-Wire receptacles and networks. For a list of suitable 1-Wire network cables, refer to the Connectivity Matrix table in the DS1402x 1-Wire network cables data sheet. Both adapters are based on the DS2490 USB-to-1-Wire bridge chip. Free software drivers for Windows®-based PCs can be downloaded fromwww.maximintegrated.com/1-Wiredrivers.ApplicationsiButton Initialization and DownloadDemonstrationDevelopmentSoftware Authorization

This DS9503 is an ESD protection device for 1-Wire® interfaces. In contrast to the DS9502, the DS9503 includes two 5Ω isolation resistors on chip. Although 5Ω are negligible during communication, they represent a high impedance relative to the conducting diode during an ESD event. Thus, the diode absorbs the energy while the resistors further isolate and protect the circuit at the other side of the package. If used with circuits that already have a strong ESD-protection at their I/O port, the ESD protection level is raised to more than 27kV (IEC 801-2 Reference model). In case of abnormal ESD hits beyond its maximum ratings the DS9503 will eventually fail "short" thus preventing further damage.During normal operation the DS9503 behaves like a Zener diode. When the voltage exceeds the trigger voltage, the I/V characteristic of the device will "snapback" allowing the same or higher amount of current to flow, but at a significantly lower voltage. As long as a minimum current or voltage is maintained, the device will stay in the "snapback mode." If the voltage or the current falls below the holding voltage or holding current, the device will abruptly change to its normal mode and conduct only a small leakage current.