DESCRIPTION
The HCS301 from Microchip Technology Inc. is a code hopping encoder designed for secure Remote Keyless
Entry (RKE) systems. The HCS301 utilizes the KEELOQ® code hopping technology, which incorporates high security, a small package outline and low cost, to make this device a perfect solution for unidirectional remote keyless entrysystems and access control systems.

FEATURES
Security
• Programmable 28-bit serial number
• Programmable 64-bit encryption key
• Each transmission is unique
• 66-bit transmission code length
• 32-bit hopping code
• 34-bit fixed code (28-bit serial number, 4-bit button code, 2-bit status)
• Encryption keys are read protected
Operating
• 3.5V - 13.0V operation
• Four button inputs
• No additional circuitry required
• 15 functions available
• Selectable baud rate
• Automatic code word completion
• Battery low signal transmitted to receiver
• Battery low indication on LED
• Non-volatile synchronization data
Other
• Functionally identical to HCS300
• Easy-to-use programming interface
• On-chip EEPROM
• On-chip oscillator and timing components
• Button inputs have internal pull-down resistors
• Current limiting on LEDoutput
• Low external component cost

Typical Applications
The HCS301 is ideal for Remote Keyless Entry (RKE) applications. These applications include:
• Automotive RKE systems
• Automotive alarm systems
• Automotive immobilizers
• Gate and garage door openers
• Identity tokens
• Burglar alarm systems