Ultra-High-Speed Microcontroller

Please check latest availability status for a specific part variant.


The DS89C420 was the first member of Maxim's ultra-high-speed flash microcontroller product line. It featured a redesigned processor core that executed every 8051 instruction (depending on the instruction type) up to 12 times faster than the original for the same crystal speed. Typical applications saw a speed improvement of 10 times using the same code and crystal. At a maximum crystal speed of 33MHz, execution rates up to 33 million instructions per second (MIPS) could be achieved.

The DS89C420 is no longer available. It has been replaced by the DS89C430, which is the same device except that it offers the in-application programming feature for approximately the same price. Engineers interested in the DS89C420 should order the corresponding DS89C430 device as shown in the table above.

Key Features

  • 80C52 Compatible
    • 8051 Pin- and Instruction-Set Compatible
    • Four Bidirectional I/O Ports
    • Three 16-Bit Timer Counters
    • 256 Bytes Scratchpad RAM
  • On-Chip Memory
    • 16kB Flash Memory
    • In-System Programmable through Serial Port
    • 1kB SRAM for MOVX
  • ROMSIZE Feature
    • Selects Internal Program Memory Size from 0 to 16k
    • Allows Access to Entire External Memory Map
    • Dynamically Adjustable by Software
  • High-Speed Architecture
    • 1 Clock-Per-Machine Cycle
    • DC to 33MHz Operation
    • Single-Cycle Instruction in 30ns
    • Optional Variable Length MOVX to Access Fast/Slow Peripherals
    • Dual Data Pointers with Auto Increment/Decrement and Toggle Select
    • Supports Four Paged Modes
  • Power Management Mode
    • Programmable Clock Divider
    • Automatic Hardware and Software Exit
  • Two Full-Duplex Serial Ports
  • Programmable Watchdog Timer
  • 13 Interrupt Sources (Six External)
  • Five Levels of Interrupt Priority
  • Power-Fail Reset
  • Early Warning Power-Fail Interrupt


  • Appliances (Washers, Microwaves, Etc.)
  • Automotive Test Equipment
  • Building Energy Control and Management
  • Consumer Electronics
  • Data Logging
  • Gaming Equipment
  • Industrial Control and Automation
  • Magstripe
  • Motor Control
  • Programmable Logic Controllers
  • Reader/Scanner
  • Security and Door Access Control
  • Telephones
  • Uninterruptible Power Supplies
  • Vending
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

Quality Management System >
Environmental Management System >


Related Resources

ChipDNA Secure Arm Cortex M4 Microcontroller

    High-Efficiency Microcontroller for Secure Element IoT
  • Secure Element
  • Power Management Maximizes Operating Time for Battery Applications
  • Multiple Peripherals for System Control

Low-Power Arm Cortex-M4 Microcontroller with Contactless Radio for Secure Applications

  • High-Efficiency Microcontroller for Secure Battery-Powered Applications
  • Scalable Cached External Memory Interfaces
  • Security Features Facilitates System-Level Protection