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Analog Devices Inc./Maxim Integrated DS87C520-QNL+T&R
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- Part No.:
- DS87C520-QNL+T&R
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Microcontrollers
- Package:
- 44-LCC (J-Lead)
- Datasheet:
-
DS87C520-QNL+T&R.pdf
- Description:
- IC MCU 8BIT 16KB OTP 44PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,319
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Product details
Overview
DS87C520-QNL+T&R from Maxim Integrated is a high-speed, 8051-compatible microcontroller with 16kB on-chip EPROM, 1kB MOVX-accessible SRAM, 256 bytes of scratchpad RAM, three 16-bit timer/counters, and two full-duplex hardware serial ports. It operates at up to 33MHz (121ns single-cycle instruction), supports -40°C to +85°C industrial temperature range, and is packaged in 44-pin PLCC for embedded control in instrumentation and industrial automation.
For engineers reviewing the DS87C520-QNL+T&R datasheet, DS87C520-QNL+T&R pinout, DS87C520-QNL+T&R application, or DS87C520-QNL+T&R equivalent, key selection considerations include its 4-clock-per-machine-cycle architecture, ROMSIZE register for dynamic internal/external memory mapping, dual data pointer for accelerated block transfers, Power Management Mode for low-power operation, and EMI reduction via ALE disable - all critical for legacy 8051 upgrade paths and timing-sensitive real-time systems.
Technical Context
The DS87C520-QNL+T&R implements a redesigned 8051 core executing instructions in 4 clocks per machine cycle (vs. 12 in standard 8051), delivering ~2.5× average speed improvement at identical crystal frequency. Its memory subsystem includes configurable ROMSIZE (0–16kB) and DME-controlled 1kB on-chip SRAM accessible via MOVX, enabling flexible boot-from-flash or hybrid internal/external program/data layouts.
Hardware peripherals include two independent serial ports (UART0/UART1), seven additional interrupt sources beyond standard 8051 (INT2–INT5, EXF2, IE5), programmable watchdog timer, power-fail reset with early-warning interrupt, and stretchable MOVX timing (2–9 cycles) for seamless interfacing to slow peripherals or legacy memory without glue logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core Architecture | 8051-compatible, 4-clock-per-machine-cycle execution (vs. 12 in legacy 8051) |
| Max Clock Frequency | 33MHz crystal input → 82.5MHz apparent instruction throughput |
| On-Chip Memory | 16kB EPROM (0000h–3FFFh) + 1kB MOVX SRAM (0000h–03FFh) + 256B direct RAM |
| Timer/Counter Resources | Three 16-bit timers/counters; Timer 2 supports capture/reload via P1.0/P1.1 |
| Serial Interfaces | Two full-duplex UARTs: UART0 (P3.0/RXD0, P3.1/TXD0), UART1 (P1.2/RXD1, P1.3/TXD1) |
| Power Management | Software-selectable clock division (÷64 or ÷1024) reduces CPU speed and power consumption |
| EMI Control | ALE signal disable via PMR.ALEOFF bit eliminates unnecessary address latch pulses |
Pinout & Package
DS87C520-QNL+T&R is housed in a 44-pin Plastic Leaded Chip Carrier (PLCC) package with J-lead geometry, rated for -40°C to +85°C operation and RoHS-compliant (lead-free).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| P1.2 / RXD1 | Serial Port 1 Input | Receives asynchronous serial data for second UART; enables dual-serial communication without software emulation |
| P1.3 / TXD1 | Serial Port 1 Output | Transmits asynchronous serial data for second UART; supports simultaneous host/device or peer-to-peer protocols |
| PMR.2 / ALEOFF | Special Function Register Bit | Writing '1' disables ALE output to reduce electromagnetic emissions during non-memory-access periods |
| ROMSIZE[2:0] | Configuration Register (C2h) | Software-selectable on-chip ROM size (0–16kB); enables dynamic remapping to access external Flash as boot device |
| DME1:DME0 | Data Memory Enable Bits (PMR.1:.0) | Selects MOVX target: internal 1kB SRAM (0000h–03FFh) or external memory map (0000h–FFFFh) |
Key Features
| Feature | Design Value |
|---|---|
| 4-Cycle Machine Architecture | Executes most instructions in 1 machine cycle (121ns @33MHz), eliminating dummy cycles for 2.5× average speed gain over standard 8051 |
| Dual Data Pointer (DPTR0/DPTR1) | Accelerates block memory moves by eliminating DPTR reload overhead; enables zero-wait-state memcpy between internal/external spaces |
| Stretchable MOVX Timing | Configurable 2–9 machine-cycle MOVX strobes (CKCON[2:0]) allow reliable interface to slow peripherals (LCDs, UARTs) without external wait-state logic |
| ROMSIZE Dynamic Mapping | Software-adjustable internal ROM boundary (0–16kB) permits booting from external Flash while retaining access to on-chip firmware for recovery or dual-bank updates |
| Power Management Mode | Reduces effective CPU speed to 187.5kHz or 11.7kHz (@12MHz crystal) for battery-powered operation while preserving full peripheral functionality |
Applications
| Industrial PLC I/O Controller | Legacy 8051 System Upgrade |
|---|---|
Use Scenario: Real-time monitoring and control of discrete sensors/actuators in factory-floor PLC modules with deterministic response under 1ms. IC Role / Device Role / Timing Role: Primary controller executing ladder logic interpreter; uses Timer 0/1 for precise I/O scan timing and UART1 for Modbus RTU slave communication. Use Value: 4-cycle core ensures consistent 250μs instruction latency across code base, enabling tighter control loop timing than standard 8051 at same clock rate. | Use Scenario: Drop-in replacement for aging 8051-based medical infusion pump controllers requiring extended lifecycle support and enhanced diagnostics. IC Role / Device Role / Timing Role: Host MCU managing motor control, pressure sensing, and HMI; leverages second UART for isolated service port and watchdog timer for safety-critical reset supervision. Use Value: Pin- and instruction-set compatibility allows reuse of existing PCB layout and firmware, while ROMSIZE and dual DPTR simplify addition of bootloader and data logging features. |
| Smart Energy Meter Communication Hub | Test Equipment Embedded Controller |
Use Scenario: Aggregating and preprocessing data from multiple metering ICs before transmission via RF or PLC modem in ANSI C12.19-compliant meters. IC Role / Device Role / Timing Role: Data concentrator MCU using UART0 for metrology IC SPI bridging and UART1 for modem AT-command interface; employs MOVX stretch to match slow SPI clock rates. Use Value: Configurable MOVX timing eliminates need for external clock dividers or FIFO buffers when interfacing to legacy metrology chips with <1MHz SPI clocks. | Use Scenario: Embedded controller in automated test equipment managing relay matrices, signal routing, and calibration data storage across multiple instrument slots. IC Role / Device Role / Timing Role: Central sequencer coordinating parallel test sequences; uses dual DPTR for rapid transfer of calibration coefficients from EEPROM to SRAM and ROMSIZE to isolate test firmware from user application space. Use Value: 1kB on-chip MOVX SRAM provides dedicated, low-latency buffer space for real-time waveform generation and measurement result caching without external memory contention. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8051-compatible microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS83C520-QNL | Factory mask ROM version (no EPROM reprogrammability); identical speed, memory, and peripheral specs | Suitable for high-volume, cost-sensitive production where firmware is fixed and unchangeable post-manufacture | Select DS83C520-QNL only when firmware is finalized and volume justifies mask ROM NRE costs |
| AT89C51RD2-RLTUM | 8051 core with 64kB Flash, 1.25kB RAM, but 12-clock architecture; max 40MHz operation, no dual UART or ROMSIZE feature | Lacks hardware UART1 and dynamic memory remapping; requires software UART emulation for second serial channel | Choose AT89C51RD2-RLTUM only if Flash reprogrammability is mandatory and dual UART is not required |
Compared with DS87C520-QNL+T&R, DS83C520-QNL offers identical performance with non-reprogrammable mask ROM for cost-driven volume production, while AT89C51RD2-RLTUM trades architectural speed and dual-hardware-serial capability for field-upgradable Flash - making DS87C520-QNL+T&R optimal for timing-critical, dual-serial industrial upgrades where EPROM flexibility and deterministic latency are essential.
Availability
DS87C520-QNL+T&R is available at Aetrix Electronics and suitable for industrial automation, test equipment, and smart metering applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for DS87C520-QNL+T&R 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, medical, and communications markets.
The DS87C520-QNL+T&R belongs to Maxim's high-speed 8051-compatible microcontroller family, engineered specifically to extend the lifecycle of legacy 8051-based systems with enhanced performance, dual serial interfaces, and flexible memory mapping - without requiring board redesign.
FAQ
What is the maximum operating frequency of the DS87C520-QNL+T&R?
The DS87C520-QNL+T&R supports a maximum crystal frequency of 33MHz, enabling single-cycle instruction execution in 121ns and delivering an effective processing throughput equivalent to 82.5MHz in standard 8051 terms. This speed is achievable across its full -40°C to +85°C industrial temperature range, with timing validated per Maxim's electrical specifications.
Does the DS87C520-QNL+T&R support in-system programming (ISP)?
No, the DS87C520-QNL+T&R contains factory-programmed EPROM and does not support in-system programming. Programming requires UV erasure (via its windowed CERDIP variant) or EPROM programmer hardware prior to system integration. For field-upgradable alternatives, consider flash-based 8051 derivatives - but note that DS87C520-QNL+T&R prioritizes deterministic timing and pin compatibility over reprogrammability.
How does the ROMSIZE feature work in the DS87C520-QNL+T&R?
The ROMSIZE register (SFR C2h) in DS87C520-QNL+T&R lets software dynamically configure the upper boundary of on-chip EPROM visibility (0–16kB). Setting RMS2:RMS0 to 101 enables full 16kB; setting to 011 restricts visible ROM to 4kB (0000h–0FFFh), freeing addresses 1000h–3FFFh for external Flash access - enabling secure boot-from-external-memory without hardware changes.
Can the DS87C520-QNL+T&R operate in low-power modes?
Yes, the DS87C520-QNL+T&R implements Power Management Mode (PMM) via PMR register bits CD1:CD0. Software can select clock division by 64 or 1024, reducing effective machine cycle rate to 187.5kHz or 11.7kHz at 12MHz crystal - proportionally lowering dynamic power while maintaining full peripheral operation and interrupt responsiveness.
Is the DS87C520-QNL+T&R pin-compatible with standard 8051 microcontrollers?
Yes, the DS87C520-QNL+T&R is fully pin-compatible with standard 8051-family devices in all supported packages (including 44-pin PLCC), preserving identical signal assignments for P0–P3, RST, XTAL1/XTAL2, EA, PSEN, ALE, RD, and WR. This allows direct socket replacement in existing 8051 designs without PCB modification, though timing-critical code may require adjustment due to its 4-cycle architecture.
DS87C520-QNL+T&R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- 44-LCC (J-Lead)
- Series:
- 87C
- Packaging:
- Tape & Reel (TR)
- 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:
- 16KB (16K x 8)
- Program Memory Type:
- OTP
- 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:
DS87C520-QNL+T&R FAQ
1.How can I place an order for DS87C520-QNL+T&R through Aetrix?
Please submit a Request for Quotation (RFQ) for DS87C520-QNL+T&R 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 DS87C520-QNL+T&R reliable?
The price and inventory of DS87C520-QNL+T&R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS87C520-QNL+T&R is usually 5 days.
3.What payment methods are accepted for DS87C520-QNL+T&R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS87C520-QNL+T&R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS87C520-QNL+T&R?
DS87C520-QNL+T&R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS87C520-QNL+T&R 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 DS87C520-QNL+T&R?
For technical support, including DS87C520-QNL+T&R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS87C520-QNL+T&R requirements.
6.How does Aetrix verify that DS87C520-QNL+T&R is sourced from the original manufacturer or authorized distributors?
All DS87C520-QNL+T&R 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 DS87C520-QNL+T&R meets industry standards.
7.What is the process for return or replacement of DS87C520-QNL+T&R?
All DS87C520-QNL+T&R units undergo pre-shipment inspection (PSI). If there is an issue with DS87C520-QNL+T&R, 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 DS87C520-QNL+T&R part is unused and in its original packaging.
Return procedure for DS87C520-QNL+T&R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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