Summary

The Software Architecture document defines the structure and organization of your medical device software according to IEC 62304 standards. It identifies software items, their interconnections, security measures, and deployment requirements, providing the foundation for software development and verification activities.

Why is Software Architecture important?

Software architecture documentation is mandatory under IEC 62304 for medical device software development. It provides the blueprint that guides your development team and demonstrates to regulators that your software is systematically designed and properly structured. The architecture ensures that all software components work together safely and effectively to deliver the intended medical functionality. Without proper architecture documentation, you cannot demonstrate that your software design is appropriate for its intended use, that risks have been properly considered, or that verification activities will be comprehensive. The architecture also serves as the foundation for change control and maintenance throughout the product lifecycle.

Regulatory Context

Under 21 CFR Part 820.30 (Design Controls) and FDA Software as Medical Device Guidance:
  • Software architecture must be documented as part of design inputs
  • Must demonstrate systematic software development approach
  • Architecture must support verification and validation activities
  • Cybersecurity considerations must be integrated into architecture design
Special attention required for:
  • Software as Medical Device (SaMD) classification and risk categorization
  • Cybersecurity framework implementation per FDA guidance
  • Software lifecycle processes documentation
  • Third-party software (SOUP) integration and risk assessment

Guide

Understanding Software Architecture

Software architecture defines the high-level structure of your medical device software. It identifies software items (components), their relationships, and how they work together to deliver medical functionality. The architecture should be detailed enough for auditors to understand your software organization but high-level enough to remain stable throughout development.

Software Items and Decomposition

According to IEC 62304, your software system consists of:
  • Software System: The complete integrated collection of software items
  • Software Items: Identifiable parts of the software that can be separately developed and tested
  • Software Units: The lowest level components that are not further decomposed
Structure your software items logically based on functionality, not just technical implementation. Common software items include:
  • Frontend/User Interface: Components that users interact with directly
  • Backend/Processing Engine: Core logic and data processing components
  • Database/Storage: Data persistence and retrieval components
  • Communication/Interface: Components that handle external communications
  • Medical Algorithm: Core medical functionality and calculations

Software Connections and Deployment

Document how your software items connect and communicate:
  • Infrastructure: Where each software item is deployed (cloud services, local hardware, mobile devices)
  • Hardware Requirements: Minimum specifications needed for each component
  • Operating Systems: Supported platforms and versions
  • Connections: Data flow and communication between software items
This information is crucial for risk assessment, verification planning, and cybersecurity analysis.

Security and Data Protection

Your architecture must address:
  • Encryption: How sensitive data is protected in transit and at rest
  • Authentication: User verification and access control mechanisms
  • Data Security: Protection of patient health information
  • Network Security: Secure communication protocols and network protection

Backup and Data Integrity

Document your approach to:
  • Data Backup: Frequency, location, and methods for data backup
  • Recovery Procedures: How data can be restored in case of failure
  • Data Integrity: Measures to ensure data accuracy and completeness
  • Business Continuity: How the system maintains availability

Minimum System Requirements

Specify the minimum requirements for end-user systems:
  • Hardware: CPU, memory, storage, and connectivity requirements
  • Software: Operating system versions, browser requirements, runtime environments
  • Network: Bandwidth, connectivity, and protocol requirements
  • Peripherals: Any required external devices or accessories

Example

Scenario: You’re developing a remote patient monitoring system that collects vital signs data from wearable devices and provides analysis to healthcare providers. Your system needs to handle real-time data processing, secure storage, and clinical decision support.

Software Items Table

Software ItemDescriptionProgramming Language (Version)Framework (Version)
Mobile AppPatient interface for data viewing and device pairingSwift (5.8), Kotlin (1.8)iOS SDK (16.0), Android SDK (33)
Web DashboardClinician interface for patient monitoring and alertsTypeScript (5.0)React (18.2), Node.js (18.16)
Data Processing EngineReal-time vital signs analysis and alert generationPython (3.11)FastAPI (0.100), NumPy (1.24)
Database SystemSecure storage of patient data and clinical recordsSQLPostgreSQL (15.3)
Device GatewayCommunication interface with wearable monitoring devicesC++ (17)Embedded Linux, Bluetooth LE

Software Connections Table

Software ItemInfrastructureHardware RequirementsOperating SystemConnections
Mobile AppUser devices2GB RAM, 1GB storageiOS 14+, Android 10+Data Processing Engine, Device Gateway
Web DashboardAWS Cloud4GB RAM, 2 vCPUUbuntu 22.04 LTSData Processing Engine, Database System
Data Processing EngineAWS Cloud8GB RAM, 4 vCPUUbuntu 22.04 LTSMobile App, Web Dashboard, Database System
Database SystemAWS RDS16GB RAM, 4 vCPUPostgreSQL on LinuxData Processing Engine
Device GatewayEdge device1GB RAM, ARM processorEmbedded LinuxMobile App, wearable devices

Security Implementation

The system implements end-to-end encryption using AES-256 for data at rest and TLS 1.3 for data in transit. Patient authentication uses OAuth 2.0 with multi-factor authentication. All API communications are secured with JWT tokens and rate limiting. Healthcare provider access is controlled through role-based permissions with audit logging of all data access.

Backup Procedures

Patient data is automatically backed up to encrypted AWS S3 storage every 4 hours. Database snapshots are created daily and retained for 30 days. Critical system configurations are version-controlled and backed up to separate geographic regions. Recovery procedures can restore full system functionality within 2 hours of any component failure.

Minimum User System Requirements

  • For Mobile App: iOS 14.0+ or Android 10+, 2GB RAM, 1GB available storage, Bluetooth 5.0+, internet connectivity
  • For Web Dashboard: Modern web browser (Chrome 100+, Firefox 100+, Safari 15+), 4GB RAM, broadband internet connection (5 Mbps minimum)
  • For Wearable Devices: Bluetooth Low Energy 5.0+, compatible with iOS/Android pairing protocols

Q&A