HCS370T/SL

Specialized ICS Overview

The HCS370T/SL is a KEELOQ code hopping encoder manufactured by Microchip Technology, housed in a 14-SOIC surface-mount package. It operates on a supply voltage ranging from 2.05V to 5.5V and features six button inputs with internal pull-down resistors. The device integrates an onboard EEPROM for storing two programmable 64-bit encoder keys, two 32-bit serial numbers, and two 60-bit seed values. It supports dual encoder functionality, allowing independent configuration via the SHIFT pin. The transmission length is 67 or 69 bits, incorporating a 32-bit hopping code generated by a nonlinear encryption algorithm to prevent code scanning and grabbing attacks.

Specialized ICS Feature Summary

• KEELOQ Code Hopping Security: Utilizes a 32-bit block cipher with 64-bit crypt keys to generate unique, unpredictable transmission codes.
• Dual Encoder Capability: Supports two distinct sets of security parameters (keys, serial numbers, seeds) selectable via the SHIFT input pin.
• Integrated Power Management: Includes a step-up voltage regulator and low-voltage detector to indicate battery status in transmissions.
• Flexible Modulation Support: Compatible with PWM, VPWM, PPM, and Manchester modulation formats with selectable baud rates.

Specialized ICS Applications

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

Specialized ICS Procurement Notes

Verify the specific ordering suffix 'SL' against official Microchip documentation to confirm tape and reel packaging details. Confirm that the component meets current RoHS compliance standards as specified in the datasheet. Ensure compatibility with existing decoder infrastructure before integration.

Specialized ICS Selection Notes

Select this encoder for applications requiring high-security unidirectional authentication where resistance to code scanning is critical. The dual encoder feature allows for flexible manufacturing configurations. Ensure the system design accommodates the required modulation format and baud rate settings configured via the onboard EEPROM.

Specialized ICS Part Context

The HCS370 belongs to the KEELOQ family of secure access controllers. It is designed to replace fixed-code transmitters in legacy systems to mitigate security vulnerabilities associated with code grabbing and brute-force attacks. The device is intended for use in conjunction with compatible decoders such as the HCS5XX series.

Specialized ICS Replacement Considerations

Direct replacements must support the KEELOQ algorithm and similar pinout configurations. Verify that any substitute component offers comparable security features, including read-protected EEPROM storage for crypt keys and synchronization counters.

Specialized ICS FAQ

How does the HCS370 prevent code grabbing attacks?

It uses KEELOQ code hopping technology, which generates a unique 32-bit encrypted code for each transmission based on a changing synchronization counter, making previously captured codes invalid.

What is the function of the SHIFT pin?

The SHIFT pin selects between two independent encoder configurations (Encoder 1 and Encoder 2), allowing the device to operate with different serial numbers, keys, and modulation settings.

Can the HCS370 transmit a low-battery warning?

Yes, it includes an onboard low-voltage detector that can be configured to transmit a VLOW status bit in the code word and optionally blink an LED when battery voltage drops below a set threshold.