Datasheet

DS9490R/DS9490B

Figure 1. DS9490R

Figure 2. DS9490B

*Note: To eject an iButton, insert a straightened paper clip into the side access hole of the DS9490B. Push

the paper clip in the direction of the iButton. A different iButton can then be inserted. The data

contact faces down and away from the embossed ‘i’. Before inserting the paper clip disconnect the

DS9490B from the USB bus.

Each USB bridge contains a unique built-in identification chip. The identification chip is a custom DS2401

that is a 64-bit ID number (see Figure 3).

Figure 3. DS2401 ID CHIP 64-BIT LASERED ROM

MSB

LSB

8-BIT

CRC CODE

12-BIT

FIXED

(000h)

36-BIT SERIAL

NUMBER

8-BIT FAMILY

CODE (81h)

MSB LSB

2 of 6