Microchip Technology ATSHA204A-XHCZ-T

The ATSHA204A provides hardware-protected symmetric keys, SHA-256-based authentication, message authentication codes, a unique 72-bit serial number, and a hardware random-number generator. This XHCZ-T variant communicates over a single-wire SDA line. The SCL pin is ignored in single-wire mode; it is not an I2C ordering variant.

The catalog records 8-TSSOP (0.173 inch, 4.40 mm width). The manufacturer's exact XHCZ-T ordering example confirms an 8-lead TSSOP and its mechanical drawing gives a nominal 4.40 mm molded-body width, 3.00 mm body length, and 0.65 mm pin pitch. The registered canonical name is 8-TSSOP, but the workbook description combines an 8-MSOP/3.00 mm width entry; that descriptive text does not match this exact manufacturer's 4.40 mm body and must be reconciled before publication.

Layout checks

• Use the controlled 4.40 mm-body, eight-lead TSSOP drawing.
• Confirm 0.65 mm lead pitch and pin-1 index.
• Distinguish body width from the 3.00 mm body length.
• Check single-wire SCL handling and local SDA routing.

The registered 8-TSSOP JPG is absent locally and returns HTTP 404 on the production site. This draft is not publishable until the image is restored and verified against the 4.40 mm package.

The manufacturer's top-view TSSOP pin diagram and package-pin table assign the following functions.

Do not design this single-wire part as if it were the I2C XHDA ordering option.

Sleep, active-current, and timing figures vary by supply, temperature, pin state, and test conditions; use the complete manufacturer tables for electrical design.

ATSHA204A-XHDA-T shares the TSSOP family but uses I2C rather than the XHCZ single-wire interface. Other ATSHA204A package options differ in footprint and packaging. None is an unconditional drop-in substitute: check exact interface, key provisioning, host firmware, pin behavior, package drawing, temperature, qualification, and lifecycle. No internal substitute link is provided without an exact API match and an approved technical relationship.

Microchip Technology's ATSHA204A complete datasheet explicitly lists ATSHA204A-XHCZ-T as an 8-lead TSSOP, tape-and-reel, single-wire part. Its package drawing specifies the 4.40 mm body width. The document marks the TSSOP option as not recommended for new designs; confirm the current manufacturer lifecycle and controlled drawing before design release.

Check package dimensions, pin-1 index, reel labeling, lot traceability, and authorized material documentation. The datasheet cautions that the full ordering code does not appear on the package; do not infer the interface variant from top marking alone. Validate the provisioned configuration and a host challenge-response test. A catalog listing does not prove provenance or secure key loading.

Security depends on key management, personalization, host implementation, and system threat analysis. The exact 4.40 mm TSSOP drawing and single-wire pin behavior control this part; the workbook's mixed 8-TSSOP/8-MSOP description requires correction. Publication remains blocked until the correct package JPG is online, visually checked, and all technical-source conflicts are closed.