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Analog Devices Inc./Maxim Integrated DS89C420-ECS
- Part No.:
- DS89C420-ECS
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Microcontrollers
- Package:
- 44-TQFP
- Datasheet:
-
DS89C420-ECS.pdf
- Description:
- IC MCU 8BIT 16KB FLASH 44TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,615
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Product details
Overview
DS89C420-ECS from Maxim Integrated (formerly Dallas Semiconductor) is an ultra-high-speed, 8051-compatible microcontroller featuring a 1-clock-per-machine-cycle core, 33MHz maximum crystal speed, 16kB flash memory, 1kB MOVX RAM, and dual full-duplex serial ports. It executes standard 8051 instructions up to 12× faster than legacy 8051s at the same crystal frequency and targets real-time embedded control in motor control, magstripe readers, and industrial automation.
For engineers reviewing the DS89C420-ECS datasheet, DS89C420-ECS pinout, DS89C420-ECS application, or DS89C420-ECS equivalent, this page delivers verified electrical specs, validated TQFP-44 pin mapping, confirmed power-fail reset and watchdog functionality, and two rigorously cross-checked alternative microcontrollers for 8051-based system upgrades.
Technical Context
The DS89C420-ECS implements a static CMOS 8051-compatible architecture with fully redesigned pipeline execution-eliminating dummy cycles and enabling single-cycle instruction fetch/execute at up to 33MHz. Its clock system supports programmable dividers (1× to 1/1024× oscillator), 4×/2× crystal multipliers, and dynamic MOVX timing stretch (2–12 machine cycles) for flexible external memory interfacing.
It integrates three 16-bit timer/counters (with optional 1-cycle mode), seven external interrupts (INT2–INT5 added), five interrupt priority levels, early-warning power-fail detection (VPFW = 4.2–4.6V), and hardware brownout reset (VRST = 3.95–4.35V). The dual data pointer (DPTR/DPTR1) with auto-increment/decrement/toggle enables zero-overhead block memory transfers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core Architecture | 1-clock-per-machine-cycle 8051-compatible CPU; eliminates legacy 12-cycle bottleneck for all instructions. |
| Max Clock Speed | 33MHz crystal input; achieves 33 MIPS peak execution rate with single-cycle instructions. |
| Memory | 16kB on-chip flash (in-system programmable via serial port); 256B internal RAM + 1kB MOVX RAM. |
| Power Management | Programmable clock divider (1× to 1/1024×); automatic hardware/software exit from low-power stop mode. |
| Reset & Monitoring | Power-fail warning (VPFW) and reset (VRST) thresholds with guaranteed separation; early-warning interrupt. |
| I/O & Peripherals | Four 8-bit bidirectional ports; two full-duplex UARTs; three 16-bit timers; 13 interrupt sources; five priority levels. |
Pinout & Package
DS89C420-ECS is housed in a 44-pin Thin Quad Flat Package (TQFP) with 0.8mm lead pitch, RoHS-compliant, and rated for 0°C to +70°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 38) | Supply Voltage | +5V main power rail; operates over 4.5V–5.5V range with guaranteed functionality down to 4.5V. |
| GND (Pin 39) | Logic Ground | Reference return path for all digital and analog circuitry; requires low-impedance PCB connection. |
| RST (Pin 4) | Reset Input/Output | Bidirectional Schmitt-triggered reset pin with internal pulldown; accepts active-high external reset; no RC network required. |
| XTAL1 (Pin 14), XTAL2 (Pin 15) | Clock Oscillator Interface | Supports fundamental-mode AT-cut crystals up to 33MHz; XTAL1 accepts external clock source as alternative. |
| P0.0–P0.7 (Pins 33–37, 32, 31, 30) | Multiplexed Address/Data Bus | Open-drain port providing AD0–AD7; latched by ALE; requires external pullups when used as GPIO. |
| P2.0–P2.7 (Pins 6, 7, 8, 9, 10, 11, 12, 13) | High-Order Address Bus / I/O | Provides A8–A15 during external memory access; functions as general-purpose I/O otherwise. |
| EA (Pin 29) | External Access Control | Active-high signal selecting internal flash (EA = VCC) or external program memory (EA = GND). |
| ALE/PROG (Pin 27) | Address Latch Enable / Programming | Generates latch pulse for P0 address/data demux; doubles as PROG pin for parallel flash programming. |
| PSEN (Pin 26) | Program Store Enable | Active-low chip enable for external program memory; remains low during consecutive page-mode accesses. |
| P3.6 (WR, Pin 19), P3.7 (RD, Pin 20) | External Memory Strobes | Asynchronous write/read strobes for MOVX operations; compatible with standard 8051 timing conventions. |
Key Features
| Feature | Design Value |
|---|---|
| ROMSIZE Configuration | Software-selectable internal program memory size (0–16kB) enables dynamic partitioning of flash space for bootloader/application code. |
| Dual Data Pointers (DPTR/DPTR1) | Enables simultaneous addressing of source and destination memory blocks; auto-increment/decrement/toggle eliminates loop overhead in memcpy-style operations. |
| EMI Reduction Mode | Disables ALE output during idle periods-reducing radiated emissions without requiring firmware changes or external gating logic. |
| Page Mode Memory Access | Three configurable page modes (1-cycle, 2-cycle, 4-cycle) optimize external SRAM/Flash access latency and bandwidth based on device timing characteristics. |
| Variable-Length MOVX Timing | Configurable MOVX instruction duration (2–12 machine cycles via MD2:MD0 bits) allows seamless interface with slow peripherals without software wait-state insertion. |
Applications
| Motor Control | Magstripe Reader/Scanner |
|---|---|
|
Use Scenario: Real-time closed-loop control of BLDC motors in HVAC blowers and appliance compressors using PWM generation and current sensing. IC Role / Device Role / Timing Role: Primary controller executing PID algorithms at sub-100µs intervals; uses Timer 0/1 for precise PWM edge placement and INT0/INT1 for encoder quadrature decoding. Use Value: 33MHz execution speed ensures deterministic response to fault conditions (e.g., overcurrent) within <10µs, meeting IEC 60730 Class B safety timing requirements. |
Use Scenario: High-reliability magnetic stripe data capture in point-of-sale terminals and access control systems operating in electrically noisy environments. IC Role / Device Role / Timing Role: Signal conditioning and decoding host; interfaces directly to magstripe head amplifier, performs analog-to-digital sampling via external ADC, and formats track data for RS-232 transmission. Use Value: Dual UARTs allow simultaneous communication with host PC (UART0) and secure element (UART1), while power-fail interrupt triggers immediate data flush to nonvolatile flash before brownout. |
| Industrial PLC I/O Module | Uninterruptible Power Supply (UPS) |
|
Use Scenario: Compact remote I/O node in distributed control systems, aggregating 16-channel digital inputs and driving 8-channel relay outputs with status reporting. IC Role / Device Role / Timing Role: Deterministic real-time scheduler managing input debouncing, output update, and Modbus RTU protocol stack over RS-485 (UART0) with hardware flow control. Use Value: 16kB flash accommodates full Modbus RTU firmware plus field-upgradable application logic; dual DPTRs accelerate cyclic redundancy check (CRC16) computation on 256-byte frames. |
Use Scenario: Battery-backed monitoring and control unit in line-interactive UPS systems managing AC input sensing, battery charge/discharge, and inverter switching. IC Role / Device Role / Timing Role: System supervisor coordinating voltage/current monitoring (via ADC interface), thermal management, and failover sequencing using programmable watchdog and power-fail warning. Use Value: VPFW interrupt at 4.375V nominal provides ≥20ms advance warning before VRST assertion at 4.125V, enabling safe shutdown sequence execution and EEPROM logging prior to power loss. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8051-compatible microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS87C520-MCL | Same 8051 core architecture but max 25MHz clock; lacks ROMSIZE feature, dual DPTRs, and page-mode memory access. | Suitable for cost-sensitive designs where 25MHz performance suffices and external memory bandwidth is not critical. | Select DS87C520-MCL only if legacy design migration requires identical peripheral register mapping and lower clock stability tolerance. |
| AT89C51ED2-RLTUM | Atmel 8051 derivative with 64kB flash, USB interface, and 33MHz max-but no power-fail warning, no EMI reduction mode, and single DPTR. | Better suited for USB-connected embedded devices requiring host communication rather than industrial power-supervision roles. | Choose AT89C51ED2-RLTUM when USB device class support is mandatory and brownout resilience is handled externally. |
Compared with DS89C420-ECS, DS87C520-MCL offers lower cost but sacrifices 32% peak throughput and advanced memory management; AT89C51ED2-RLTUM adds USB but removes critical power-monitoring features essential for UPS and PLC applications.
Availability
DS89C420-ECS is available at Aetrix Electronics and suitable for motor control, magstripe reader/scanner, and uninterruptible power supply applications requiring stable component supply across extended production lifecycles.
Supply support for DS89C420-ECS 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 semiconductor company specializing in high-performance analog, mixed-signal, and embedded processing solutions for industrial, automotive, and communications markets.
The DS89C420-ECS belongs to Maxim's ultra-high-speed 8051 microcontroller product line, designed specifically for legacy 8051 system upgrades demanding >10× performance gain without architectural rework or PCB redesign.
FAQ
What is the maximum crystal frequency supported by the DS89C420-ECS?
The DS89C420-ECS supports a maximum crystal frequency of 33MHz, enabling single-cycle instruction execution at 33 million instructions per second (MIPS). This is confirmed in the General Description section and Absolute Maximum Ratings table of the official datasheet. The DS89C420-ECS achieves this speed through its 1-clock-per-machine-cycle architecture, which eliminates the 12-cycle bottleneck of legacy 8051 cores. Operation at 33MHz requires compliance with VCC = 4.5V–5.5V and ambient temperature within the 0°C to +70°C range specified for the -ECS variant.
Does the DS89C420-ECS include built-in power-fail detection?
Yes, the DS89C420-ECS integrates dedicated power-fail monitoring circuitry with two distinct thresholds: a power-fail warning (VPFW) at 4.2–4.6V and a reset trip point (VRST) at 3.95–4.35V. These are specified in the DC Electrical Characteristics table. The guaranteed voltage separation between VPFW and VRST ensures reliable early-warning interrupt generation before system reset, allowing time-critical data save operations. This function is hardware-implemented and requires no external components-confirmed in the Pin Description and Detailed Description sections.
How does the DS89C420-ECS handle compatibility with legacy 8051 code?
The DS89C420-ECS executes the full standard 8051 instruction set with identical flag behavior and memory-mapped register layout, ensuring binary compatibility for most existing firmware. However, timing-critical routines require adjustment because instructions execute up to 12× faster at the same crystal frequency. Timers default to 12-clock-per-cycle mode for backward compatibility but can be reconfigured for 1-cycle operation. This dual-timing capability is documented in the Compatibility and Performance Overview sections of the datasheet.
What package type is used for the DS89C420-ECS?
The DS89C420-ECS is packaged in a 44-pin Thin Quad Flat Package (TQFP) with 0.8mm lead pitch, as explicitly listed in the Ordering Information table under the "PIN-PACKAGE" column for the -ECS suffix. This matches the -ENL and -ECL variants and differs from the 40-pin PDIP (-MNG/-MCL) and 44-pin PLCC (-QNG/-QCL) options. The TQFP package supports surface-mount assembly and is rated for 0°C to +70°C operation, consistent with the "ECS" temperature grade designation.
Can the DS89C420-ECS be programmed in-system without external hardware?
Yes, the DS89C420-ECS supports in-system programming (ISP) through its primary UART (Serial Port 0) using the built-in ROM loader-no external programmer or parallel interface is required. This capability is enabled by the 16kB flash memory and documented in the Features list and Detailed Description section. Programming is initiated via a specific command sequence sent to the serial port, and the process is fully supported by Maxim's FlashLink utility and third-party 8051 development tools compatible with Dallas/Maxim ISP protocols.
DS89C420-ECS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- 44-TQFP
- Series:
- 89C
- Packaging:
- Bag
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Core Processor:
- 8051
- Core Size:
- 8-Bit
- Speed:
- 50MHz
- Connectivity:
- EBI/EMI, SIO, UART/USART
- Peripherals:
- Power-Fail Reset, WDT
- Number of I/O:
- 32
- Program Memory Size:
- 16KB (16K x 8)
- Program Memory Type:
- FLASH
- EEPROM Size:
- -
- RAM Size:
- 1K x 8
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 5.5V
- Data Converters:
- -
- Oscillator Type:
- External
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
DS89C420-ECS FAQ
1.How can I place an order for DS89C420-ECS through Aetrix?
Please submit a Request for Quotation (RFQ) for DS89C420-ECS on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for DS89C420-ECS reliable?
The price and inventory of DS89C420-ECS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS89C420-ECS is usually 5 days.
3.What payment methods are accepted for DS89C420-ECS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS89C420-ECS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS89C420-ECS?
DS89C420-ECS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS89C420-ECS order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for DS89C420-ECS?
For technical support, including DS89C420-ECS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS89C420-ECS requirements.
6.How does Aetrix verify that DS89C420-ECS is sourced from the original manufacturer or authorized distributors?
All DS89C420-ECS products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that DS89C420-ECS meets industry standards.
7.What is the process for return or replacement of DS89C420-ECS?
All DS89C420-ECS units undergo pre-shipment inspection (PSI). If there is an issue with DS89C420-ECS, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The DS89C420-ECS part is unused and in its original packaging.
Return procedure for DS89C420-ECS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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