The DS2703 is a battery pack authentication IC that implements a challenge/response scheme that uses the SHA-1 to authenticate a battery pack for a host system such as a cell phone, PDA, or other portable computing device. Integrating the DS2703 in the battery pack allows the host to guard against unauthorized packs that could introduce unknown functions or substandard operation and even cause harm.

Using its stored 64-bit secret key and unique 64-bit ROM ID, the DS2703’s SHA-1 engine processes a 64-bit host-transmitted challenge to produce a 160-bit response word for transmission back to the host. The secret key, which is securely stored on-chip, never transmits between the battery and the host. This produces a high degree of authentication security between a host system and its battery pack or other peripheral devices.

The DS2703 integrates a thermistor multiplexer that allows one battery pack contact to handle both data and thermistor functions. This feature saves both space and money by enabling the use of only three contacts between the pack and host: Pack+, Pack–, and data/thermistor. The data/thermistor contact also serves as the power line to the device because the DS2703 is directly powered through its 1-Wire data interface.

The DS2703 is available in a tiny eight-pin microSOP package. It costs $0.77 for 10,000-piece quantities.

Dallas Semiconductor Corp.
www.maxim-ic.com