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Analog Devices Inc./Maxim Integrated DS89C450-QNL+
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- Part No.:
- DS89C450-QNL+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Microcontrollers
- Package:
- 44-LCC (J-Lead)
- Datasheet:
-
DS89C450-QNL+.pdf
- Description:
- IC MCU 8BIT 64KB FLASH 44PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,886
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Product details
Overview
DS89C450-QNL+ from Maxim Integrated is a RoHS-compliant, 64kB flash, 44-pin PLCC ultra-high-speed 8051-compatible microcontroller executing instructions at up to 33 MIPS (1 instruction per clock cycle) with DC–33MHz operation, 2× full-duplex serial ports, and 1kB MOVX SRAM - deployed in industrial HVAC control, power-supply monitoring, and motor-control firmware.
For engineers reviewing the DS89C450-QNL+ datasheet, DS89C450-QNL+ pinout, DS89C450-QNL+ application, or DS89C450-QNL+ equivalent, key selection criteria include its 1-cycle-per-instruction core, ROMSIZE programmable memory mapping, dual data pointers with auto-increment, and EMI-reduction ALE disable capability for noise-sensitive embedded systems.
Technical Context
The DS89C450-QNL+ implements a fully static CMOS 8051-compatible architecture with a redesigned core eliminating wasted cycles - achieving one machine cycle per crystal clock versus legacy 12-cycle timing. It supports five memory-access modes (including page modes 1/2) and configurable MOVX stretch cycles (2–9 cycles) for flexible external peripheral interfacing.
Its power management includes programmable clock division (1× to 1024×), automatic hardware/software exit from idle/stop modes, and early-warning power-fail interrupt with VPFW = 4.2–4.6V and VRST = 3.95–4.35V thresholds - enabling robust brownout handling without external reset ICs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core Architecture | Single-cycle 8051-compatible CPU delivering 33 MIPS at 33MHz - eliminates timing recalibration for legacy 8051 code except critical delay loops. |
| Flash Memory | 64kB on-chip flash with 10,000 write/erase cycles and 100-year data retention - supports in-application programming via serial port or parallel programmer. |
| RAM | 256B internal RAM + 1kB dedicated MOVX SRAM - enables high-speed external memory access without contention on Port 0. |
| Operating Voltage | 4.5V–5.5V supply range with guaranteed operation down to 4.5V - compatible with standard 5V industrial logic rails. |
| Temperature Range | -40°C to +85°C ambient operating range - qualified for industrial control, building automation, and UPS monitoring environments. |
| Power Consumption | 75–110mA active current at 33MHz; 1–100µA stop mode (bandgap disabled) - enables low-power sleep states in battery-backed systems. |
| Interrupt System | 13 interrupt sources (6 external), 5 priority levels, and dedicated INT2–INT5 pins on Port 1 - supports deterministic real-time response in motor control and safety-critical I/O. |
Pinout & Package
DS89C450-QNL+ uses a 44-pin Plastic Leaded Chip Carrier (PLCC) package with J-lead configuration, 1.27mm pitch, and body size 16.59mm × 16.59mm - suitable for through-hole mounting and reflow-soldered industrial PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 12, 22, 23, 34) | Supply voltage input | +5V primary power rail; four distributed pins reduce IR drop and improve noise immunity in high-current operation. |
| GND (Pin 1, 23, 34, 44) | Logic ground reference | Four dedicated ground pins ensure stable return path for digital I/O, timers, and serial peripherals. |
| RST (Pin 10) | Active-high reset input | Bidirectional Schmitt-trigger input with internal 50–200kΩ pulldown - eliminates need for external RC network during power-up. |
| XTAL1/XTAL2 (Pin 21, 20) | Crystal oscillator interface | Supports fundamental-mode AT-cut crystals (1–33MHz); XTAL1 accepts external clock source when crystal omitted. |
| P0.0–P0.7 (Pin 39–32) | Multiplexed address/data bus | Open-drain port with weak pullups; latched by ALE to provide AD0–AD7 during external memory access - requires external pullups only in pure I/O mode. |
| P1.0–P1.7 (Pin 2–9) | General-purpose I/O with alternate functions | Includes T2/T2EX, RXD1/TXD1, and INT2–INT5 - enables timer capture, second UART, and five edge-triggered interrupts without GPIO expansion. |
| P2.0–P2.7 (Pin 24–31) | High-order address bus / I/O | Provides A8–A15 during external memory access; supports page mode 1/2 addressing for fast burst reads/writes to external RAM or peripherals. |
| P3.0–P3.7 (Pin 11–18) | Primary I/O with serial/timer/control functions | Hosts RXD0/TXD0, INT0/INT1, T0/T1, WR/RD - delivers full 8051-compatible peripheral set plus external memory strobes in compact PLCC layout. |
| EA (Pin 35) | External access select | Logic-high enables internal 64kB flash execution; grounded forces external program memory fetch - allows seamless transition between boot-from-flash and external loader modes. |
| ALE/PROG (Pin 33) | Address latch enable / programming mode | Generates strobe for external address latch (e.g., 74LS373); toggles to PROG function during parallel programming - supports both in-system and factory programming. |
Key Features
| Feature | Design Value |
|---|---|
| One-clock-per-machine-cycle execution | Eliminates 11 wasted clocks per instruction vs. legacy 8051 - reduces firmware latency and enables deterministic real-time loop timing at 33MHz. |
| Dual data pointers with toggle select | Enables simultaneous access to two memory regions (e.g., source/destination buffers) without register save/restore - accelerates memcpy, DMA-like transfers, and protocol stack processing. |
| ROMSIZE programmable memory mapping | Software-selectable internal program memory size (0–64kB) - permits dynamic remapping of external memory space for bootloader/firmware partitioning without hardware changes. |
| EMI reduction mode | Disables ALE output during non-memory-access cycles - lowers radiated emissions in EMC-critical applications like medical devices and industrial drives. |
| Power-fail warning and reset | Dedicated VPFW (4.2–4.6V) and VRST (3.95–4.35V) thresholds with early-warning interrupt - allows safe state save and controlled shutdown before brownout collapse. |
Applications
| Industrial HVAC Control | Uninterruptible Power Supply Monitoring |
|---|---|
|
Use Scenario: Real-time temperature, humidity, and airflow regulation in commercial building management systems using analog sensors and relay drivers. IC Role / Device Role / Timing Role: Primary controller executing PID algorithms, managing dual UARTs for BACnet/MODBUS communication, and driving PWM fan stages via Timer 2. Use Value: 33 MIPS throughput ensures sub-millisecond sensor sampling and actuator response - meeting ASHRAE 135 compliance for closed-loop HVAC stability. |
Use Scenario: Continuous AC line monitoring, battery voltage/current tracking, and inverter control in 1–10kVA UPS units with SNMP remote management. IC Role / Device Role / Timing Role: System supervisor handling power-fail interrupt, watchdog reset supervision, and dual serial ports for local RS-232 and remote Ethernet gateway communication. Use Value: VPFW threshold triggers 20ms pre-brownout alert - enabling safe transfer to battery backup and logging of grid anomaly events before shutdown. |
| Motor Control Interface | Vending Machine Controller |
|
Use Scenario: Closed-loop stepper/servo motor positioning in CNC equipment with encoder feedback and limit-switch inputs. IC Role / Device Role / Timing Role: Motion sequencer using INT2–INT5 for quadrature decoding, Timer 0/1 for pulse-width modulation, and P0/P2 for parallel step/direction outputs. Use Value: Dual DPTRs accelerate encoder position buffer updates and motion profile lookups - reducing jitter in 10kHz step pulses for smooth acceleration curves. |
Use Scenario: Cashless payment integration, inventory tracking, and multi-vendor dispensing logic in smart vending kiosks with magstripe, RFID, and LCD interfaces. IC Role / Device Role / Timing Role: Central coordinator managing serial magstripe reader (P3.0/P3.1), contactless RFID UART (P1.2/P1.3), and 4×4 keypad scan via Port 1/Port 2. Use Value: 64kB flash accommodates multiple vendor firmware images and secure bootloader - supporting over-the-air updates without external memory expansion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8051-compatible microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS89C430-QNL+ | 16kB flash, identical 44-pin PLCC package and pinout - shares same core, peripherals, and instruction set. | Limited to smaller firmware images; suitable where code size < 16kB and cost sensitivity outweighs future upgrade headroom. | Select when flash overhead is constrained and no bootloader or dual-application partitioning is required. |
| DS89C450-ENL+ | Same 64kB flash and features, but in 44-pin TQFP package - exposes identical signal mapping with finer pitch (0.8mm) and surface-mount compatibility. | Better suited for high-density PCBs and automated SMT assembly; lacks PLCC's through-hole serviceability and thermal mass. | Choose for volume production with reflow-only processes and space-constrained layouts requiring minimal board area. |
Compared with DS89C430-QNL+, the DS89C450-QNL+ provides 4× more flash for complex protocols and field-upgradable firmware, while DS89C450-ENL+ offers identical functionality in a smaller footprint - making DS89C450-QNL+ optimal for industrial designs needing serviceable through-hole mounting and long-term code scalability.
Availability
DS89C450-QNL+ is available at Aetrix Electronics and suitable for industrial HVAC control, uninterruptible power supply monitoring, and motor-control interface applications requiring stable component supply across extended product lifecycles.
Supply support for DS89C450-QNL+ 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 (now part of Analog Devices) designs precision analog, mixed-signal, and high-reliability microcontrollers for industrial, automotive, and communications markets - emphasizing robustness, low-power operation, and system-level integration.
The DS89C450-QNL+ belongs to Maxim's Ultra-High-Speed Flash Microcontroller family, engineered to replace legacy 8051s in performance-critical embedded systems where deterministic timing, EMI resilience, and in-field firmware updates are mandatory.
FAQ
What is the maximum clock frequency supported by the DS89C450-QNL+?
The DS89C450-QNL+ supports a maximum system clock frequency of 33MHz with DC-to-33MHz operation. Its one-cycle-per-instruction architecture achieves 33 million instructions per second (MIPS) at this rate - confirmed in the Absolute Maximum Ratings and AC Characteristics sections of the official datasheet. This exceeds legacy 8051 performance by up to 12× at the same crystal speed.
Does the DS89C450-QNL+ support in-system programming via serial interface?
Yes, the DS89C450-QNL+ supports in-system programming (ISP) through its serial port (UART0 or UART1) using ROM-resident or user-defined loader software. The 64kB flash memory is in-application programmable without removing the device from the circuit - a capability explicitly documented in the "On-Chip Memory" feature list and Flash Programming Characteristics table.
How does the power-fail warning feature work on the DS89C450-QNL+?
The DS89C450-QNL+ integrates a dedicated power-fail warning comparator with VPFW threshold of 4.2–4.6V. When VCC drops below VPFW but remains above VRST (3.95–4.35V), it asserts an early-warning interrupt - allowing firmware to execute critical save routines before reset occurs. This is distinct from the power-on reset and is verified in the DC Electrical Characteristics table.
Is the DS89C450-QNL+ pin-compatible with standard 8051 microcontrollers?
Yes, the DS89C450-QNL+ is pin-compatible with standard 8051-family devices in all three packages (PDIP, PLCC, TQFP). Its Port 0–3, RST, XTAL1/XTAL2, EA, PSEN, and ALE signals map identically - enabling socket replacement in existing 8051 designs. This compatibility is explicitly stated in the "Compatibility" section and Pin Description tables of the datasheet.
What are the key differences between DS89C450-QNL+ and DS89C430-QNL+?
The DS89C450-QNL+ and DS89C430-QNL+ share identical packaging (44-pin PLCC), pinout, core architecture, and peripherals - differing only in flash capacity: 64kB vs. 16kB. Both support the same ROMSIZE feature, dual DPTRs, and EMI reduction mode. This makes DS89C450-QNL+ a direct drop-in upgrade where larger firmware images or bootloader partitioning are required.
DS89C450-QNL+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- 44-LCC (J-Lead)
- Series:
- 89C
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- 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:
- 64KB (64K 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
DS89C450-QNL+ FAQ
1.How can I place an order for DS89C450-QNL+ through Aetrix?
Please submit a Request for Quotation (RFQ) for DS89C450-QNL+ 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 DS89C450-QNL+ reliable?
The price and inventory of DS89C450-QNL+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS89C450-QNL+ is usually 5 days.
3.What payment methods are accepted for DS89C450-QNL+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS89C450-QNL+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS89C450-QNL+?
DS89C450-QNL+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS89C450-QNL+ 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 DS89C450-QNL+?
For technical support, including DS89C450-QNL+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS89C450-QNL+ requirements.
6.How does Aetrix verify that DS89C450-QNL+ is sourced from the original manufacturer or authorized distributors?
All DS89C450-QNL+ 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 DS89C450-QNL+ meets industry standards.
7.What is the process for return or replacement of DS89C450-QNL+?
All DS89C450-QNL+ units undergo pre-shipment inspection (PSI). If there is an issue with DS89C450-QNL+, 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 DS89C450-QNL+ part is unused and in its original packaging.
Return procedure for DS89C450-QNL+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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