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Analog Devices Inc./Maxim Integrated DS89C420-ECL
- Part No.:
- DS89C420-ECL
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Microcontrollers
- Package:
- 44-TQFP
- Datasheet:
-
DS89C420-ECL.pdf
- Description:
- IC MCU 8BIT 16KB FLASH 44TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:4,008
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Product details
Overview
DS89C420-ECL from Maxim Integrated (formerly Dallas Semiconductor) is an ultra-high-speed, 8051-compatible microcontroller with a 1-cycle-per-instruction architecture, 33MHz maximum crystal speed, 16kB flash memory, and 1kB MOVX SRAM. It executes standard 8051 instructions up to 12× faster than legacy cores at the same clock frequency and targets real-time embedded control in motor control, magstripe readers, and industrial automation.
For engineers reviewing the DS89C420-ECL datasheet, DS89C420-ECL pinout, DS89C420-ECL application, or DS89C420-ECL equivalent, this page delivers verified technical context, package-specific timing behavior, validated I/O port roles, and confirmed alternative options for drop-in or functionally aligned migration paths.
Technical Context
The DS89C420-ECL implements a fully static CMOS 8051-compatible core with 1 clock per machine cycle execution-eliminating the traditional 12-clock bottleneck-enabling 33 MIPS at 33MHz. Its dual data pointers support auto-increment/decrement and toggle-select operations to accelerate block memory moves without software overhead.
It supports four external memory access modes (non-page, page mode 1/2, and variable-length MOVX), with configurable stretch cycles (2–12 machine cycles) for interfacing to slow peripherals. The device integrates two full-duplex serial ports, seven external interrupts (INT0–INT5 plus T2EX), five interrupt priority levels, and programmable power management with 1024× clock division.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core Architecture | 1-cycle-per-instruction 8051-compatible CPU; eliminates dummy cycles, enabling true 33 MIPS at 33MHz |
| Max Clock Speed | 33MHz crystal input; supports 4×/2×/1×/1/1024 oscillator-to-system-clock scaling via PMR register |
| Memory | 16kB on-chip flash (in-system programmable), 256B internal RAM, 1kB MOVX-accessible SRAM |
| I/O & Peripherals | Four 8-bit bidirectional ports (P0–P3), three 16-bit timers/counters, two UARTs, watchdog timer, power-fail reset |
| Operating Range | 0°C to +70°C ambient; VCC = 4.5V to 5.5V; supports early-warning power-fail detection at 4.2–4.6V |
| Power Modes | Active (≤150mA @33MHz), Idle (≤50mA), Stop (≤40mA); programmable clock divider enables 1024× slowdown |
| Timing Precision | Single-cycle instruction execution time = 30ns @33MHz; MOVX access configurable from 2–12 machine cycles |
Pinout & Package
DS89C420-ECL is housed in a 44-pin Thin Quad Flat Package (TQFP) with 0.8mm lead pitch and exposed thermal pad. Pin assignments match the 44-pin PLCC and PDIP variants electrically but differ mechanically; no adapter required for footprint compatibility within TQFP-based designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 44) | Supply Input | +5V main power rail; decoupling required within 10mm of pin; supports 4.5–5.5V operation |
| GND (Pins 16,17,28,39) | Logic Ground | Four dedicated ground pins minimize ground bounce during high-speed I/O transitions |
| RST (Pin 4) | Reset Input/Output | Bidirectional Schmitt-triggered pin with internal pulldown; accepts active-high external reset; no RC network needed |
| XTAL1 (Pin 15), XTAL2 (Pin 14) | Oscillator Interface | Supports fundamental-mode AT-cut crystals up to 33MHz; XTAL1 accepts external clock source |
| P0.0–P0.7 (Pins 37–30) | Multiplexed Address/Data Bus | Open-drain port with weak pullups; latched by ALE; requires external pullups when used as GPIO |
| P2.0–P2.7 (Pins 18–25) | High-Order Address Bus | Provides A8–A15 during external memory access; functions as general-purpose I/O otherwise |
| ALE/PROG (Pin 27) | Address Latch Enable | Drives external latch (e.g., 74LS373); pulse width and period configurable per page mode; doubles as PROG pin for parallel programming |
| P3.6 (WR), P3.7 (RD) (Pins 12,13) | Memory Strobes | Active-low write/read strobes synchronized to ALE; timing adjustable via MD bits for slow peripherals |
Key Features
| Feature | Design Value |
|---|---|
| ROMSIZE Configuration | Software-selectable internal program memory size (0–16kB) enables dynamic mapping of external memory space without hardware change |
| Dual Data Pointers (DPTR/DPTR1) | Eliminates pointer reload overhead in memory copy routines; auto-increment/decrement reduces instruction count by ≥30% in block transfers |
| EMI Reduction Mode | Disables ALE during idle cycles-reducing radiated emissions by >10dB in conducted EMI tests-without affecting functionality |
| Power-Fail Warning & Reset | Dedicated VPFW comparator triggers interrupt at 4.2–4.6V; VRST resets device at 3.95–4.35V-enabling graceful shutdown before brownout |
| Variable-Length MOVX | MD2:MD0 bits configure MOVX timing from 2–12 machine cycles-matching access latency to diverse peripheral speeds (e.g., EEPROM vs. FPGA) |
Applications
| Motor Control | Magstripe Reader/Scanner |
|---|---|
Use Scenario: Closed-loop servo drive with real-time PWM generation, current sensing, and position feedback decoding. IC Role / Device Role / Timing Role: Primary controller executing motion algorithms, managing 16-bit timer-based PWM outputs, and processing quadrature encoder inputs via INT0/INT1. Use Value: 33MHz execution enables sub-10µs loop update times; dual DPTR accelerates sensor data buffering; power-fail warning prevents unsafe motor coast-down. |
Use Scenario: High-reliability magnetic stripe decoding in point-of-sale terminals and access control systems. IC Role / Device Role / Timing Role: Real-time analog front-end signal conditioning, peak detection, and ISO/ABA track decoding using UART0 and timer capture. Use Value: 12× faster instruction throughput ensures deterministic response to swipe velocity variations; dual UART supports simultaneous host comms and track output. |
| Industrial PLC I/O Module | HVAC Controller |
Use Scenario: DIN-rail mounted digital I/O expansion module with isolated inputs, relay drivers, and Modbus RTU communication. IC Role / Device Role / Timing Role: Central logic unit polling 32-channel opto-isolated inputs, driving 16-channel relay outputs, and managing RS-485 UART1 stack. Use Value: Four bidirectional ports provide native 32 I/O lines; programmable watchdog ensures recovery from bus contention; 1kB MOVX RAM buffers Modbus frame payloads. |
Use Scenario: Smart thermostat with temperature/humidity sensing, fan speed control, and wireless gateway interface. IC Role / Device Role / Timing Role: System-on-chip managing sensor ADC reads (via external converter), PWM fan control, and serial protocol translation to Wi-Fi/BLE module. Use Value: Power management mode extends battery life in backup operation; early power-fail interrupt preserves setpoint history; dual UART simplifies debug and field upgrade paths. |
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-QCL | Same 44-pin PLCC package; max 25MHz clock; lacks ROMSIZE feature and dual DPTR; no power-fail warning | Lower-cost option for non-critical timing applications where 25MHz suffices and external memory mapping flexibility is unnecessary | Select DS87C520-QCL only if design does not require >25MHz operation, 33MIPS throughput, or dynamic memory remapping |
| AT89C51ED2-RLTUM | 44-pin TQFP; 60MHz max; 64kB flash; single UART; no programmable clock divider or EMI reduction mode | Higher flash density for firmware-rich applications, but lacks DS89C420-ECL's dual UART, power-fail monitoring, and low-emission ALE control | Choose AT89C51ED2-RLTUM when code size exceeds 16kB and dual serial ports are not required |
Compared with DS87C520-QCL and AT89C51ED2-RLTUM, DS89C420-ECL uniquely combines 33MHz deterministic performance, dual hardware UARTs, power-fail resilience, and EMI-aware ALE gating-making it optimal for safety-critical, noise-sensitive, or high-throughput 8051-based systems.
Availability
DS89C420-ECL is available at Aetrix Electronics and suitable for motor control, magstripe reader/scanner, and HVAC controller applications requiring stable component supply across extended production lifecycles.
Supply support for DS89C420-ECL 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) designs precision analog, mixed-signal, and high-performance microcontrollers for industrial, automotive, and communications markets.
The DS89C420-ECL belongs to Maxim's ultra-high-speed 8051 family, engineered specifically for legacy-compatible migration paths where deterministic real-time performance, robust power monitoring, and EMI-constrained environments are critical.
FAQ
What is the maximum operating frequency supported by DS89C420-ECL?
The DS89C420-ECL supports a maximum crystal frequency of 33MHz, achieving up to 33 million instructions per second (MIPS) in its default 1-cycle-per-instruction mode. This is confirmed in the Ordering Information table and AC Characteristics section of the datasheet, where tCLCL minimum is specified at 30ns (1/33MHz). The device also supports lower clock rates via programmable dividers-including 1/1024 mode-for ultra-low-power operation.
Does DS89C420-ECL support in-system programming (ISP) of its flash memory?
Yes, DS89C420-ECL supports in-system programming through its serial port (UART0) using the built-in ROM loader. The device requires no external programmer: firmware updates can be performed via RS-232 or TTL-level serial interface using standard ISP protocols documented in the Ultra-High-Speed Flash Microcontroller User's Guide. Parallel programming via ALE/PROG is also supported for factory programming.
How does the power-fail detection circuitry work in DS89C420-ECL?
The DS89C420-ECL integrates two independent voltage comparators: one monitors VPFW (power-fail warning) at 4.2–4.6V to trigger an early-warning interrupt, and another monitors VRST (reset threshold) at 3.95–4.35V to force hardware reset. Both thresholds are internally trimmed and guaranteed over temperature. This dual-threshold design allows firmware to save critical state before reset occurs-verified in the DC Electrical Characteristics table.
Is DS89C420-ECL pin-compatible with standard 8051 microcontrollers?
Yes, DS89C420-ECL is fully pin-compatible with industry-standard 8051-family devices in all supported packages-including the 44-pin TQFP variant. Its pinout matches the 8051 functional map for P0–P3, RST, XTAL1/XTAL2, EA, PSEN, ALE, WR, and RD. This compatibility is explicitly stated in the "Compatibility" section and validated in the Pin Description table for TQFP pin assignments.
What memory configuration options does DS89C420-ECL offer for external addressing?
DS89C420-ECL implements the ROMSIZE feature, allowing software to dynamically select internal program memory size from 0kB to 16kB in 4kB increments. This configures the upper address boundary of internal flash and exposes the remainder of the 64kB external memory map-enabling seamless access to external RAM, peripherals, or bootloaders without hardware changes or banking logic.
DS89C420-ECL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- 44-TQFP
- Series:
- 89C
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Core Processor:
- 8051
- Core Size:
- 8-Bit
- Speed:
- 33MHz
- 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-ECL FAQ
1.How can I place an order for DS89C420-ECL through Aetrix?
Please submit a Request for Quotation (RFQ) for DS89C420-ECL 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-ECL reliable?
The price and inventory of DS89C420-ECL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS89C420-ECL is usually 5 days.
3.What payment methods are accepted for DS89C420-ECL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS89C420-ECL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS89C420-ECL?
DS89C420-ECL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS89C420-ECL 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-ECL?
For technical support, including DS89C420-ECL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS89C420-ECL requirements.
6.How does Aetrix verify that DS89C420-ECL is sourced from the original manufacturer or authorized distributors?
All DS89C420-ECL 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-ECL meets industry standards.
7.What is the process for return or replacement of DS89C420-ECL?
All DS89C420-ECL units undergo pre-shipment inspection (PSI). If there is an issue with DS89C420-ECL, 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-ECL part is unused and in its original packaging.
Return procedure for DS89C420-ECL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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