HCS362-I/SN

Specialized ICS Overview

The HCS362-I/SN is a KEELOQ code hopping encoder manufactured by Microchip Technology, designed for secure remote keyless entry systems. It operates within a voltage range of 2.0V to 6.3V and features four button inputs supporting up to 15 functions. The device generates a unique 69-bit transmission stream per activation, comprising a 32-bit encrypted hopping code, a 28/32-bit serial number, and status bits. Security is ensured through two programmable 64-bit encryption keys and a 60-bit seed stored in read-protected on-chip EEPROM. The component utilizes an internal tunable RC oscillator and supports PWM or Manchester modulation formats.

Specialized ICS Feature Summary

• KEELOQ Code Hopping: Generates unique 69-bit transmissions using a 32-bit hopping code to prevent code grabbing and replay attacks.
• High Security Encryption: Features two programmable 64-bit encryption keys and a 60-bit seed, with all security data stored in read-protected on-chip EEPROM.
• Flexible Configuration: Supports selectable baud rates, code word blanking, minimum code word completion, and configurable low-voltage detection thresholds.
• Dual Encoder Operation: Capable of operating as two distinct encoders sharing one synchronization counter, selected via the SHIFT input pin.

Specialized ICS Applications

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

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 during manufacturing to load the crypt keys and serial numbers, as these are not user-accessible post-production. Ensure compatibility with the receiver's decoder firmware for proper learning and synchronization procedures.

Specialized ICS Selection Notes

Select the HCS362-I/SN when a cost-effective, high-security unidirectional encoder is required for RKE applications. It is suitable for designs needing dual-key functionality or specific modulation formats like PWM or Manchester. Consider the 2.0V–6.3V operating range for battery-powered applications and verify that the system architecture supports the necessary RF PLL interface if the RFEN output is utilized.

Specialized ICS Part Context

The HCS362 is part of Microchip's KEELOQ product family, succeeding earlier models like the HCS300 series. It offers enhanced features such as a 60-bit seed (compared to 32-bit in predecessors), 2-bit CRC for error detection, and selectable 28/32-bit serial numbers. This evolution provides improved security against sophisticated code scanning while maintaining a small package outline and low component count.

Specialized ICS Replacement Considerations

Public documentation identifies the HCS361 as a compatible alternative offering higher security levels. The HCS360 is noted as a lower-cost option within the same family. Designers should verify pinout compatibility and software/firmware adjustments required when migrating between these KEELOQ encoder variants.

Specialized ICS FAQ

How does the HCS362 prevent code grabbing attacks?

The HCS362 uses KEELOQ code hopping technology, where each transmission includes a 32-bit encrypted hopping code derived from a changing synchronization counter. This ensures every transmitted code is unique, rendering captured codes useless for retransmission.

What is the function of the SHIFT input pin?

The SHIFT pin allows the HCS362 to operate as a dual encoder. A logic 1 selects the first crypt key, while a logic 0 selects the second crypt key, enabling the device to control two different systems while sharing a single synchronization counter.

Can the encryption keys be read externally?

No. The encryption keys, serial number, and configuration data are stored in an on-chip EEPROM array that is read-protected. Access is only possible during production programming, preventing unauthorized extraction of security parameters.