Analog Devices Inc./Maxim Integrated DS5240F-1N5+

Overview

DS5240F-1N5+ from Maxim Integrated (formerly Dallas Semiconductor) is a high-speed, 8051-compatible secure microcontroller with tamper-resistant physical security architecture, 25MHz operation, -40°C to +85°C temperature range, and 100-pin MQFP package. It integrates a modulo arithmetic accelerator (MAA) for up to 4096-bit PKI operations, on-chip random number generator, true-time clock with alarm/wakeup, and dual self-destruct inputs (SDI1/SDI2) for cryptographic zeroization in banking-grade secure systems.

For engineers reviewing the DS5240F-1N5+ datasheet, DS5240F-1N5+ pinout, DS5240F-1N5+ application, or DS5240F-1N5+ equivalent, this device serves as a FIPS 140– and Common Criteria–validated security processor for encrypted external memory execution, rapid SRAM zeroization, and environmental tamper detection in payment terminals, HSMs, and trusted platform modules.

Technical Context

The DS5240F-1N5+ implements an asynchronous ring oscillator and PLL-isolated internal clocking system to decouple cryptographic timing from external noise sources. Its 4-clock/machine-cycle 8051 core executes single-cycle instructions in 160ns and supports linear addressing of up to 4MB program and 4MB data space via a dedicated nonmultiplexed byte-wide bus.

Security logic includes fine-line top-metal intrusion detection, on-chip voltage/temperature sensors triggering destructive reset, and two independent tamper response paths: SDI1 initiates full zeroization (external memory, cache, key registers, selected SRAM), while SDI2 generates a software-controllable interrupt for adaptive countermeasure activation.

Key Specifications

Pinout & Package

DS5240F-1N5+ is housed in a 100-pin plastic MQFP (Metric Quad Flat Package) with 0.5mm lead pitch, thermally enhanced for industrial embedded deployment. Pin functions are validated per Maxim's DS5240 abridged datasheet Rev 041802 and official pinout diagrams.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar secure microcontroller applications.

Compared with DS5240F-1N5+, DS5250F-1N5+ delivers higher cryptographic throughput and future-proof algorithm support in pin-compatible form, while STM32L562VE trades FIPS-certified physical security for flexible peripheral integration and ecosystem maturity-making DS5240F-1N5+ optimal where regulatory validation and deterministic zeroization are mandatory.

Availability

DS5240F-1N5+ is available at Aetrix Electronics and suitable for payment terminal security modules, hardware security modules (HSMs), and trusted platform module (TPM) implementations requiring stable component supply, long-term industrial temperature support (-40°C to +85°C), and FIPS 140–validated tamper response.

Supply support for DS5240F-1N5+ 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 (acquired by Analog Devices in 2021) is a U.S.-based semiconductor company specializing in analog, mixed-signal, and secure ICs for industrial, communications, and computing markets.

The DS5240F-1N5+ belongs to Maxim's legacy Dallas Semiconductor secure microcontroller product line, engineered specifically for financial transaction security, cryptographic key protection, and tamper-evident embedded systems requiring Common Criteria EAL4+ certification.

FAQ

What is the operating temperature range of the DS5240F-1N5+?

The DS5240F-1N5+ is rated for industrial operation from -40°C to +85°C. This extended range ensures reliable performance in uncontrolled environments such as outdoor payment kiosks, industrial gateways, and secure access panels where ambient temperatures fluctuate significantly. The device's on-chip temperature sensor actively monitors die temperature and can trigger a tamper response if thresholds are exceeded, reinforcing its role in physically secured applications.

Does the DS5240F-1N5+ support both single-DES and triple-DES encryption?

Yes, the DS5240F-1N5+ includes a user-accessible DES engine supporting both single-DES and triple-DES (3DES) modes with 112-bit keys. The 3DES implementation uses two independent key words generated by the on-chip random number generator, ensuring cryptographically strong key material. This engine operates on external memory bus traffic, encrypting program data to prevent eavesdropping-critical for FIPS 140–compliant deployments where external flash or EEPROM stores executable code.

How does the DS5240F-1N5+ handle power failure events?

The DS5240F-1N5+ incorporates on-chip power detection circuitry that asserts a PF (power-fail) interrupt before VCC drops below operational threshold. This early-warning signal allows firmware to execute secure state save, flush caches, and initiate controlled zeroization if needed. Simultaneously, VBAT maintains internal SRAM and RTC operation during main power loss, preserving cryptographic context and timekeeping for >10 years using a standard lithium coin cell-ensuring continuity in secure applications like HSMs and TPMs.

What is the purpose of the two self-destruct inputs (SDI1 and SDI2) on the DS5240F-1N5+?

SDI1 and SDI2 provide differentiated tamper-response capabilities: SDI1 is a hardware-driven input that immediately erases external program/data memory, cache, key registers, and designated SRAM regions-enabling FIPS 140–mandated irreversible zeroization. SDI2 functions as a standard interrupt input, allowing firmware to evaluate the tamper event (e.g., enclosure breach, voltage glitch) and execute custom countermeasures before initiating selective zeroization. This dual-path design satisfies both automated and policy-driven security workflows in DS5240F-1N5+ deployments.

Is the DS5240F-1N5+ pin-compatible with other devices in the DS5240 family?

Yes, the DS5240F-1N5+ shares identical pinout and electrical characteristics with other 100-pin variants in the DS5240 family, including DS5240F-125. Differences are limited to temperature grade (-40°C to +85°C vs. 0°C to +70°C) and ordering suffixes; no PCB layout changes are required when substituting within the same package variant. However, migration to the DS5250F-1N5+-while footprint-compatible-requires validation due to enhanced MAA and added AES engine functionality.