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NXP Semiconductors P87C51SBAA,512
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- Part No.:
- P87C51SBAA,512
- Manufacturer:
- NXP Semiconductors
- Category:
- Microcontrollers
- Package:
- 44-LCC (J-Lead)
- Datasheet:
-
P87C51SBAA,512.pdf
- Description:
- IC MCU 8BIT 4KB OTP 44PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,555
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Product details
Overview
P87C51SBAA,512 from Philips Semiconductors is an 8-bit OTP-based microcontroller in the 80C51 architecture family, featuring 4 K × 8 on-chip OTP memory, 128 × 8 RAM, three 16-bit counter/timers, and full-duplex UART - operating at up to 16 MHz across 2.7 V–5.5 V supply range in industrial temperature (0 °C to +70 °C) within a 44-pin PLCC package. It serves as a drop-in firmware-upgradeable replacement for ROM-based P80C51 variants in legacy embedded control systems.
For engineers reviewing the P87C51SBAA,512 datasheet, P87C51SBAA,512 pinout, P87C51SBAA,512 application, or P87C51SBAA,512 equivalent, this page delivers verified technical context, validated pin functions, real-world use cases, and two confirmed alternative parts - all aligned with Philips' 2000 product specification and ordering data.
Technical Context
The P87C51SBAA,512 implements a static CMOS 8051 CPU core with full backward compatibility to MCS-51 instruction set, supporting zero-frequency operation and dual power-saving modes: idle (CPU halted, peripherals active) and power-down (oscillator stopped, RAM retained down to 2.0 V). Its memory map supports 64 KB program and 64 KB data addressing space.
It integrates four 8-bit bidirectional I/O ports (P0–P3), each with Schmitt-trigger inputs and internal pull-ups (except P0, open-drain), plus dedicated serial interface (RxD/TxD), external interrupts (INT0/INT1), timer inputs (T0/T1), and Timer 2 I/O (T2/T2EX) - all mapped to fixed physical pins per PLCC-44 package layout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core Architecture | 8051-compatible 8-bit CPU with Boolean processor and static design enabling 0 Hz operation. |
| Memory | 4 K × 8 OTP (one-time programmable) program memory; 128 × 8 RAM - sufficient for compact firmware without external code storage. |
| Operating Voltage | 2.7 V to 5.5 V - supports battery-powered and mixed-voltage industrial systems without level-shifting. |
| Max Clock Frequency | 16 MHz at 2.7–5.5 V - enables deterministic real-time response with 1 µs instruction cycle at 12-tick mode. |
| I/O Ports | Four 8-bit ports (32 total lines); P0 open-drain for multiplexed address/data bus; P1–P3 quasi-bidirectional with internal pull-ups. |
| Timers & Serial | Three 16-bit timers/counters; full-duplex UART with framing error detection and automatic address recognition. |
| Power Modes | Idle mode (CPU halted, RAM/timers/UART/interrupts active); Power-down mode (oscillator off, RAM retained, wake via INT0/INT1). |
Pinout & Package
Package: Plastic Leaded Chip Carrier (PLCC), 44-pin, SOT187-2 footprint - surface-mount compatible with standard reflow profiles and socketable for prototyping.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | NIC | No internal connection - must be left unconnected or tied to ground per layout guidelines. |
| 2–9 | P1.0–P1.7 | General-purpose I/O; P1.0/T2 and P1.1/T2EX support Timer 2 capture/reload and clock-out functionality. |
| 10 | RST | Active-high reset input requiring ≥2 machine cycles (24 oscillator periods) high pulse for reliable initialization. |
| 11,13–19 | P3.0–P3.7 | Multiplexed functions: RxD/TxD (serial), INT0/INT1 (edge/level-sensitive interrupts), T0/T1 (timer inputs), WR/RD (external memory strobes). |
| 20–21 | XTAL2/XTAL1 | Crystal oscillator terminals - support external crystal (1–16 MHz) or external clock source driven into XTAL1. |
| 22 | VSS | Ground reference - requires low-impedance connection to minimize noise coupling into analog-sensitive peripherals. |
| 24–31 | P2.0–P2.7 | High-order address bus (A8–A15) during external memory access; also general-purpose I/O with internal pull-ups. |
| 32–33 | PSEN/ALE | PSEN: External program memory read strobe; ALE: Address latch enable pulse at 1/6 oscillator frequency for external bus latching. |
| 35 | EA/VPP | External Access Enable - high = execute from internal OTP; low = fetch from external memory; also receives 12.75 V during programming. |
| 36–43 | P0.7–P0.0 | Open-drain bidirectional port; multiplexed low-order address/data bus (AD7–AD0) during external memory access - requires external pull-ups. |
| 44 | VCC | Power supply input - decoupling capacitor (100 nF ceramic) required adjacent to pin for stable operation. |
Key Features
| Feature | Design Value |
|---|---|
| OTP Memory Security | Three programmable security bits prevent unauthorized readout of firmware - essential for IP protection in production units. |
| Low-EMI Operation | Configurable ALE inhibit and slew-rate-controlled outputs reduce radiated emissions - simplifies EMC compliance in industrial environments. |
| Asynchronous Port Reset | Reset can be asserted independently of oscillator stability - enables robust recovery after brown-out or supply glitch without external supervisor IC. |
| Dual Data Pointers | Two independent DPTR registers accelerate block memory moves and table lookups - improves performance in data-intensive firmware tasks. |
| Programmable Clock-Out | 50% duty-cycle clock output on P1.0 (61 Hz–4 MHz range at 16 MHz system clock) - eliminates need for external clock generator in timing-critical subsystems. |
Applications
| Industrial Motor Control | Legacy Instrumentation Interface |
|---|---|
Use Scenario: Standalone motor sequencer managing stepper/servo drive signals in HVAC actuators and valve positioners. IC Role / Device Role / Timing Role: Primary controller executing closed-loop logic, generating PWM-equivalent timing via timer interrupts, and handling RS-232 diagnostics. Use Value: 128 B RAM and 4 KB OTP provide sufficient space for motion profiles and fault-handling routines; 16 MHz max clock ensures sub-millisecond interrupt latency for torque regulation. |
Use Scenario: Retrofit module bridging analog sensor outputs (4–20 mA, thermocouple) to Modbus RTU over RS-485 in field instruments. IC Role / Device Role / Timing Role: Protocol translator with UART hardware framing, checksum calculation, and discrete I/O for status LEDs and relay control. Use Value: Full-duplex UART with framing error detection ensures robust serial communication; OTP prevents firmware tampering during field deployment. |
| Embedded Power Supply Monitor | Factory Automation I/O Node |
Use Scenario: Compact voltage/current supervisor in AC/DC power supplies, monitoring rail integrity and triggering shutdown via opto-isolated outputs. IC Role / Device Role / Timing Role: Real-time analog monitoring via external ADC interface (using P0/P2 as data/address bus), with fast-response interrupt-driven fault handling. Use Value: Three 16-bit timers allow precise timing of sampling intervals and watchdog timeouts; power-down mode reduces quiescent current to <10 µA during standby. |
Use Scenario: Distributed digital I/O expansion node in PLC backplanes, aggregating 16-channel discrete inputs/outputs over CAN or RS-485. IC Role / Device Role / Timing Role: Local intelligence hub managing debounce, edge detection, and cyclic redundancy checks before upstream reporting. Use Value: Four 8-bit ports deliver native 32 I/O lines; internal RAM retains state during brief bus interruptions; OTP ensures firmware immutability across thousands of deployed nodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| P80C51SBAA | 4 K × 8 mask ROM instead of OTP; no field-programmability; identical pinout, timing, and peripheral set. | Suitable only for high-volume, fixed-firmware deployments where ROM cost advantage outweighs flexibility. | Select when firmware is finalized and volume justifies mask ROM NRE; avoid if post-production updates or prototyping are needed. |
| AT89C51-24PI | 4 K × 8 Flash memory; 24 MHz max clock; same 44-pin PLCC package but different DC characteristics and reset timing. | Enables in-system reprogramming and faster throughput, but requires validation of timing margins and voltage tolerance in legacy designs. | Choose for new designs needing field upgrades; verify compatibility with existing 80C51 timing-critical code and external bus interfaces. |
Compared with P87C51SBAA,512, P80C51SBAA offers lower unit cost but zero field update capability, while AT89C51-24PI adds Flash flexibility and speed at the expense of stricter voltage regulation and revised reset behavior - making P87C51SBAA,512 optimal for secure, unchanging firmware in industrial retrofits.
Availability
P87C51SBAA,512 is available at Aetrix Electronics and suitable for industrial motor control, legacy instrumentation interface, embedded power supply monitoring, and factory automation I/O node applications requiring stable component supply and long-term obsolescence management.
Supply support for P87C51SBAA,512 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
Philips Semiconductors (now NXP Semiconductors) is a pioneer in integrated circuit design, delivering high-reliability, industry-standard microcontrollers since the 1980s.
The 80C51/87C51 family was engineered for cost-sensitive, resource-constrained embedded control - emphasizing silicon efficiency, broad voltage operation, and seamless migration from earlier 8051 derivatives in industrial and automotive subsystems.
FAQ
What is the maximum operating frequency of the P87C51SBAA,512?
The P87C51SBAA,512 supports a maximum clock frequency of 16 MHz across its full 2.7 V–5.5 V operating voltage range. This is specified in Philips' 2000 product documentation under the "ORDERING INFORMATION" table for the SBAA variant. At 16 MHz, the device achieves a 1 µs instruction cycle time in standard 12-clock mode, enabling deterministic real-time response for time-critical control loops.
Does the P87C51SBAA,512 include on-chip RAM, and how much is available?
Yes, the P87C51SBAA,512 includes 128 × 8 bytes of on-chip RAM - directly accessible as internal data memory. This RAM remains fully functional and retains data during idle mode, and is preserved down to 2.0 V in power-down mode. The RAM size is explicitly stated in the "FEATURES" section and confirmed in the "SELECTION TABLE" of the Philips datasheet, distinguishing it from the 256-byte RAM in 80C52/87C52 variants.
What package type and pin count does the P87C51SBAA,512 use?
The P87C51SBAA,512 uses a 44-pin Plastic Leaded Chip Carrier (PLCC) package, designated SOT187-2 in Philips' ordering information. Pin configuration matches the standard 80C51 PLCC layout, including dedicated P0–P3 ports, XTAL1/XTAL2, RST, EA/VPP, ALE, and PSEN - all verified in the "PIN CONFIGURATIONS" and "PIN DESCRIPTIONS" sections of the datasheet.
Can the P87C51SBAA,512 be programmed in-circuit, or does it require a dedicated programmer?
The P87C51SBAA,512 contains one-time programmable (OTP) memory and requires a dedicated EPROM-style programmer applying 12.75 V to the EA/VPP pin during programming. It does not support in-system programming (ISP) or in-application programming (IAP). Programming is performed once before soldering; subsequent firmware changes require device replacement - a key distinction from Flash-based alternatives like the AT89C51.
How does the power-down mode function on the P87C51SBAA,512, and how is it exited?
In power-down mode, the P87C51SBAA,512 stops the oscillator and disables all peripherals except RAM and SFRs, retaining data down to 2.0 V. It exits via hardware reset or external interrupt on INT0/INT1 - provided WUPD bit (AUXR1.3) is enabled. After exit, the oscillator requires stabilization time (<10 ms), and execution resumes from the instruction following the power-down command, preserving register and RAM contents.
P87C51SBAA,512 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Package/Case:
- 44-LCC (J-Lead)
- Series:
- 87C
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Core Processor:
- 8051
- Core Size:
- 8-Bit
- Speed:
- 16MHz
- Connectivity:
- EBI/EMI, UART/USART
- Peripherals:
- POR
- Number of I/O:
- 32
- Program Memory Size:
- 4KB (4K x 8)
- Program Memory Type:
- OTP
- EEPROM Size:
- -
- RAM Size:
- 128 x 8
- Voltage - Supply (Vcc/Vdd):
- 2.7V ~ 5.5V
- Data Converters:
- -
- Oscillator Type:
- Internal
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
P87C51SBAA,512 FAQ
1.How can I place an order for P87C51SBAA,512 through Aetrix?
Please submit a Request for Quotation (RFQ) for P87C51SBAA,512 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 P87C51SBAA,512 reliable?
The price and inventory of P87C51SBAA,512 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for P87C51SBAA,512 is usually 5 days.
3.What payment methods are accepted for P87C51SBAA,512?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for P87C51SBAA,512 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for P87C51SBAA,512?
P87C51SBAA,512 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your P87C51SBAA,512 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 P87C51SBAA,512?
For technical support, including P87C51SBAA,512 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your P87C51SBAA,512 requirements.
6.How does Aetrix verify that P87C51SBAA,512 is sourced from the original manufacturer or authorized distributors?
All P87C51SBAA,512 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 P87C51SBAA,512 meets industry standards.
7.What is the process for return or replacement of P87C51SBAA,512?
All P87C51SBAA,512 units undergo pre-shipment inspection (PSI). If there is an issue with P87C51SBAA,512, 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 P87C51SBAA,512 part is unused and in its original packaging.
Return procedure for P87C51SBAA,512:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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