Analog Devices Inc./Maxim Integrated DS2460S+

Overview

DS2460S+ from Maxim Integrated is a SHA-1 coprocessor with integrated 112-byte EEPROM, designed for secure authentication and service data validation in I²C-based host systems. It performs hardware-accelerated SHA-1 MAC generation, supports 100kHz/400kHz I²C communication, operates from 2.7V to 5.5V across -40°C to +85°C, and features three address inputs (AD0–AD2) for up to eight device addressing on one bus.

For engineers reviewing the DS2460S+ datasheet, DS2460S+ pinout, DS2460S+ application, or DS2460S+ equivalent, key selection criteria include its dedicated SHA-1 engine timing, EEPROM endurance (200k cycles per 8-byte block), IEC 1000-4-2 ±4kV ESD rating, 64-bit unique registration number, and compatibility with standard/fast-mode I²C hosts requiring tamper-resistant cryptographic services.

Technical Context

The DS2460S+ implements a fully autonomous SHA-1 computation engine that accepts up to 64 bytes of input data and produces a 20-byte MAC without host CPU intervention. Its I²C interface uses open-drain SDA/SCL with external pullups and supports slave address configuration via AD0–AD2 pins, enabling multi-device bus topology.

Internal architecture includes an 8-byte EEPROM write buffer, 64-byte SHA input buffer, and MAC output buffer, all managed through command registers accessible over I²C. The device asserts no clock stretching and requires strict adherence to I²C timing - including tHD:STA ≥ 0.6µs and tSU:DAT ≥ 100ns - to avoid bus protocol violations.

Key Specifications

Pinout & Package

DS2460S+ is housed in an 8-pin SOIC package (150 mils wide), RoHS-compliant and lead-free. Pin assignments are validated per Maxim's abridged datasheet Figure and PIN DESCRIPTION table.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SHA-1 coprocessor applications.

Compared with DS2460S+, DS2465+ replaces I²C with 1-Wire and adds AES, making it incompatible with I²C host designs; ATSHA204A upgrades to SHA-256 but reduces EEPROM size and changes cryptographic scope - neither is pin- or firmware-compatible, and both require interface and firmware redesign.

Availability

DS2460S+ is available at Aetrix Electronics and suitable for access control systems, electronic payment terminals, and utility metering applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for DS2460S+ 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

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and secure ICs for industrial, automotive, and communications markets.

The DS2460S+ belongs to Maxim's secure authentication product line, engineered specifically for hardware-accelerated cryptographic operations in resource-constrained I²C host systems where software-based SHA-1 is impractical or insecure.

FAQ

What is the primary function of the DS2460S+ in a secure system?

The DS2460S+ serves as a dedicated SHA-1 coprocessor with integrated EEPROM, offloading computationally intensive MAC generation from the host microcontroller. It enables secure authentication, digital signature validation, and one-time encryption key generation - all using hardware-accelerated SHA-1. Its role in a secure system is to ensure cryptographic integrity without exposing secrets to software execution environments.

Does the DS2460S+ support both standard-mode and fast-mode I²C communication?

Yes, the DS2460S+ supports both standard-mode (100kHz) and fast-mode (400kHz) I²C communication. Its SDA and SCL pins meet I²C electrical specifications including VOL ≤ 0.4V at 4mA sink, VIH ≥ 0.7×VCC, and tSU:DAT ≥ 100ns. No clock stretching is performed, simplifying timing analysis in host firmware.

How many devices can share the same I²C bus with the DS2460S+?

Up to eight DS2460S+ devices can operate on the same I²C bus segment. This is achieved via three binary address inputs (AD0, AD1, AD2), which configure bits A0, A2, and A4 of the 7-bit slave address. Each combination yields a unique address, eliminating the need for external multiplexers or hubs in multi-node authentication systems.

What is the EEPROM endurance specification for the DS2460S+?

The DS2460S+ EEPROM is rated for 200,000 write/erase cycles per 8-byte block at +25°C. Endurance degrades with increasing temperature per datasheet Note 2. The device supports single-byte to 8-byte write sequences, allowing fine-grained updates that extend effective lifetime beyond full-block cycling assumptions.

Is the DS2460S+ RoHS-compliant and what does the '+' suffix indicate?

Yes, the '+' suffix in DS2460S+ explicitly denotes a lead(Pb)-free and RoHS-compliant package. It is packaged in an 8-pin SOIC (150 mils) with package code S8+4, conforming to JEDEC standards and Maxim's environmental compliance requirements. The '+' does not affect electrical or functional specifications - only material content and finish.