Microchip Technology HCS412-I/SN

The HCS412 supports remote keyless entry and contactless token designs needing a unidirectional code-hopping transmission together with a bidirectional transponder challenge-response path. The encoder transmits a 69-bit code word with a 32-bit encrypted hopping field and a 37-bit fixed field. Its inductive transponder accepts a 32-bit challenge. In the exact HCS412-I/SN order code, I identifies the industrial temperature range and SN identifies an 8-lead plastic SOIC, 150 mil body.

Microchip's SN package code is an 8-lead plastic SOIC with a 150 mil body. The site's registered 8-SOIC entry corresponds to the original 0.154-inch (3.90 mm) width category. Check the manufacturer's package drawing, land pattern, and pin-1 orientation for the assembled board.

Layout checks

• Match the 8-lead SOIC footprint and pin-1 orientation to Microchip's drawing.
• Route LC0 and LC1 according to the selected inductive antenna configuration.
• Place local VDD decoupling and connect DATA to the intended transmitter circuit.

The existing normalized package registration and local JPG were checked. The illustration is not a dimensional drawing.

Microchip DS41099D pin table for the 8-pin SOIC:

The behavior of multiplexed pins depends on operating mode and configuration.

Timing and electrical values must be checked for the chosen configuration and industrial operating conditions.

HCS412/SN shares the SOIC package but is the commercial 0 to +70 °C ordering grade, so it is not a temperature-equivalent replacement in an industrial design. Other HCS encoders may differ in transmitted word, keys, reader protocol, antenna behavior, or pin functions. No internal alternative is linked without a verified exact product record.

Microchip Technology documents the HCS412 in datasheet DS41099D. Its product-identification table specifies I as −40 to +85 °C and SN as the 8-lead, 150 mil plastic SOIC. Consult the datasheet's applicable operating-mode and package tables during design.

Verify the full HCS412-I/SN order code, package marking, and lot traceability. Check programmed keys and configuration through an authorized process, then validate encoder learning and transponder responses against the target receiver.

Design the LF antenna, receiver, and key-management process as a system. Confirm mode-specific pin multiplexing, programming, synchronization, output coding, and battery behavior against DS41099D. Observe the published electrical limits across the industrial temperature range.