HCS301-I/SN

Specialized ICS Overview

The HCS301-I/SN is a code hopping encoder from Microchip Technology, part of the KEELOQ® series. It operates on a 3.5V to 13.0V supply and features four button inputs with internal pull-down resistors. The device generates a unique 66-bit transmission code for each activation, combining a 32-bit encrypted hopping code with a 34-bit fixed code containing a 28-bit serial number. It includes an on-chip oscillator, non-volatile EEPROM for storing encryption keys and synchronization data, and supports selectable baud rates. Designed for surface mount in an 8-SOIC package, it provides high security against code scanning and replay attacks.

Specialized ICS Feature Summary

• KEELOQ® Code Hopping: Generates a unique 66-bit transmission per button press using a 32-bit nonlinear encryption algorithm.
• Secure Memory: Contains 192 bits of read-protected EEPROM for a programmable 64-bit crypt key, 28-bit serial number, and synchronization counter.
• Low Voltage Indication: Transmits a VLOW bit to alert receivers when battery voltage drops below a configurable trip point.
• Flexible Configuration: Supports selectable baud rates via configuration bits and allows overflow tracking to extend synchronization range.

Specialized ICS Applications

• Automotive Remote Keyless Entry (RKE) systems
• Automotive alarm and immobilizer systems
• Gate and garage door openers
• Burglar alarm systems
• Identity tokens

Specialized ICS Procurement Notes

Verify the specific suffix 'I/SN' confirms the industrial temperature grade (-40°C to +85°C) and SOIC-8 surface mount package. Confirm that the device requires external programming to load the manufacturer's crypt key and serial number before system integration. Ensure the receiving decoder is compatible with the KEELOQ protocol and configured for the selected baud rate.

Specialized ICS Selection Notes

Select the HCS301-I/SN for unidirectional remote access applications requiring high security against code grabbing. Compare against the HCS300 if pin compatibility is required, noting the HCS301 supports higher voltages up to 13V. Consider the HCS362 for advanced encryption needs, though it may require different packaging or interface adjustments. Ensure the application design accounts for the 10ms debounce delay and automatic code word completion features.

Specialized ICS Part Context

The HCS301 is functionally identical to the HCS300 but supports a wider operating voltage range of 3.5V to 13.0V. It utilizes the patented KEELOQ technology to provide secure, one-way communication for remote control systems. The device integrates all necessary timing and encryption components, minimizing external circuitry requirements for transmitter designs.

Specialized ICS Replacement Considerations

The HCS300 is a functionally identical alternative with similar pinout and functionality, differing primarily in voltage specifications. For designs requiring enhanced security features or updated encryption algorithms, the HCS362 is a recommended successor, though it may utilize different packaging options such as SOIC-18.

Specialized ICS FAQ

How does the HCS301 prevent code replay attacks?

It uses KEELOQ code hopping technology where a 16-bit synchronization counter increments with each transmission. This ensures every transmitted code word is unique, making captured codes invalid for future use.

What is the purpose of the Seed Transmission feature?

Pressing all three buttons simultaneously transmits a 32-bit seed value stored in EEPROM. This enables 'Secure Learn' mode, allowing the receiver to derive a new crypt key without relying on standard learning methods.

Can the HCS301 transmit multiple code words if a button is held down?

Yes, the code word completion feature ensures full transmission even if the button is released early. If held longer than one code word period, it will repeat the transmission until the button is released.