Auto Electronics

Microchip introduces single-chip PKE device

Microchip Technology Inc. has introduced an 8-bit Flash microcontroller with a three-channel, low-frequency analog transponder front-end and an integrated KEELOQ cryptographic peripheral. The PIC16F639, in a 20-pin SSOP package, provides a single-chip solution for passive-keyless-entry (PKE) and other wireless authentication applications.

PKE systems enable a driver to open a vehicle door without having to press a button on a key fob. No more than 20% of remote keyless entry systems are passive, according to Willie Fitzgerald, director of marketing for Microchip’s Automotive Products Group, “but PKE should gain equilibrium within the next three-to-five years” due to its greater convenience.

The PIC16F639 transmits a low-frequency (125 kHz) signal with a range of approximately 3 m. It draws 100 ìA in operation and 1 nA in standby mode. Its KEELOQ technology is based on a proprietary, non-linear encryption algorithm that creates a unique transmission on every use, and it is designed to foil code capture and resend schemes.

The device includes a precision 8MHz oscillator with internal clock switching, up to 3.5 KB of Flash program memory, 128 bytes of RAM, 256 bytes of EEPROM, two analog comparators, an 8-bit timer and a 16-bit timer. Power management features include ultra-low-power wakeup, software-selectable brownout reset, programmable low-voltage detect, wakeup reset, and an enhanced watchdog timer.

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