Analog Devices Inc./Maxim Integrated MAX66240ESA+

The MAX66240 combines a 13.56-MHz contactless transponder, a factory-programmed 64-bit ROM identifier, user-programmable protected EEPROM and a hardware SHA-256 engine. A reader can use challenge-based message authentication to verify the tag and control protected memory operations. The SOIC package is intended for connection to a suitable external antenna.

The manufacturer's ordering table lists MAX66240ESA+ as an 8-pin SO package, -40 C to +85 C. Its package table identifies a 150-mil SOIC body; LCDChip registers this as 8-SOIC (0.154", 3.90 mm width). Confirm the controlled S8+2 outline and land pattern before PCB release.

Layout checks

• Route antenna nodes AC1 and AC2 according to the RF matching design.
• Observe the controlled pin-one orientation and keep D.N.C. pins unconnected.
• Validate the antenna and enclosure with the intended reader field.

This generic JPG illustrates the package shape, not the device-specific pinout.

For the 8-pin SOIC, the manufacturer assigns AC2 to pin 2 and AC1 to pin 3 as the two antenna connections. Pins 1 and 4 through 8 are marked D.N.C. (do not connect). These pins are not power, ground, SCL or SDA connections; use the manufacturer's SO top-view drawing for layout orientation.

RF, endurance and timing specifications depend on the manufacturer's stated test conditions and reader field; consult the controlled data sheet.

A same-size SOIC secure device is not an automatic replacement. Compare antenna connections, ISO 15693 command behavior, secret provisioning, EEPROM page protection, ROM-ID use, operating temperature, package and reader firmware. The related MAX66242 adds an I²C interface and is not assumed pin-compatible. No unverified internal substitute link is asserted.

Maxim Integrated's MAX66240 data sheet, 219-0042 Rev. 5, lists the exact MAX66240ESA+ order code, SO pin assignments, 4-Kbit EEPROM organization, RF characteristics and published ISO 15693 timing errata. Analog Devices now hosts the manufacturer document and lists the product as not recommended for new designs.

Check the complete MAX66240ESA+ order code, SOIC marking, lot documentation and traceability. Device identity, secret installation and protected-memory settings require controlled functional checks; package markings alone do not prove a provisioned authentication state.

The manufacturer data sheet documents two ISO 15693-3 timing noncompliances concerning response timing after carrier modulation and the inventory-slot EOF interval. Validate those errata with the chosen reader and firmware. Use the controlled data sheet, antenna design information and package drawing for final qualification; SHA-256 capability alone is not a system-level security certification.