Infineon Technologies SLE 4428 M2.2

Overview

SLE 4428 M2.2 from Siemens AG is an intelligent 1-KByte (1024 × 8-bit) EEPROM IC for contact-based smart cards, featuring byte-wise write protection, programmable 2-byte security code (PSC), and ISO/IEC 7816-3 synchronous serial interface. It operates at 5 V, supports ≥10⁴ write/erase cycles, and guarantees ≥10-year data retention. Used in secure financial or ID cards where tamper-resistant memory access is required.

For engineers reviewing the SLE 4428 M2.2 datasheet, SLE 4428 M2.2 pinout, SLE 4428 M2.2 application, or SLE 4428 M2.2 equivalent, key selection factors include PSC-verified write enablement, irreversible byte-level protection memory (1024 × 1 bit), open-drain I/O timing compliance with ISO 7816 Answer-to-Reset, and M2.2 wire-bonded module form factor for card embedding.

Technical Context

The SLE 4428 implements a synchronous three-wire serial interface (VCC, RST, CLK, I/O, GND) compliant with ISO/IEC 7816-3 for contact smart cards. Its PSC verification logic blocks all memory writes/erases unless the correct 2-byte code is entered - after eight failed attempts, the error counter permanently disables further PSC checks.

Memory organization includes 1024 × 8-bit EEPROM plus a separate 1024 × 1-bit protection memory. Protection bits are one-time programmable (OTP); once set, they convert target bytes to ROM. Read operations remain unrestricted regardless of protection or PSC status.

Key Specifications

Pinout & Package

Package: M2.2 wire-bonded module - designed for direct embedding into PVC or polycarbonate smart cards per ISO/IEC 7816 mechanical specifications. Not a die or bare chip; includes bond wires and encapsulation suitable for lamination.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar contact smart card EEPROM applications.

Compared with AT88SC0104CA-SH and SLC 520, the SLE 4428 M2.2 offers strict ISO 7816-3 timing fidelity and proven field reliability in high-volume financial cards, whereas alternatives trade protocol breadth or modern process benefits for minor deviations in reset behavior or protection granularity.

Availability

SLE 4428 M2.2 is available at Aetrix Electronics and suitable for financial payment cards, government ID systems, transit fare platforms, and healthcare access tokens requiring stable component supply and long-term lifecycle support.

Supply support for SLE 4428 M2.2 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Siemens AG Semiconductor Group, headquartered in Munich, Germany, developed foundational secure memory ICs for contact smart cards in the 1990s and established early ISO/IEC 7816 interoperability standards.

The SLE 44xx series was designed specifically for embedded secure credential storage in plastic cards, prioritizing tamper resistance, protocol compliance, and manufacturability in high-volume card personalization lines.

FAQ

Does the SLE 4428 M2.2 support ISO/IEC 7816-3 asynchronous communication?

No. The SLE 4428 M2.2 implements only synchronous transmission per ISO/IEC 7816-3, using CLK, RST, and I/O with defined Answer-to-Reset timing. It does not include UART logic or guard time handling required for asynchronous mode. Hardware design must align with synchronous clock-driven command framing.

Can the Programmable Security Code (PSC) be changed after initial programming?

Yes - the PSC is fully reprogrammable at any time, provided the current valid PSC is presented first. Unlike protection bits, the PSC memory location is writable multiple times. However, each change requires successful verification of the prior code, preserving access control integrity throughout the card's lifecycle.

What happens when the error counter reaches eight failed PSC attempts?

After eight consecutive incorrect PSC entries, the error counter triggers permanent lockout: no further PSC verification attempts are accepted, and all write/erase commands return invalid status. The memory remains readable, but no modifications - including PSC update - are possible. Recovery requires physical card replacement.

Is the M2.2 module RoHS-compliant or lead-free?

The original SLE 4428 M2.2 (04.94 datasheet era) predates RoHS legislation and contains lead-based solder in its wire-bonded construction. It is not RoHS-compliant. For compliant alternatives, consider Infineon's SLC 520 or newer generations explicitly marked "lead-free" and qualified to EU Directive 2011/65/EU.