NXP Semiconductors P87C51RB2BN,112

Overview

P87C51RB2BN,112 from NXP Semiconductors (formerly Philips) is an 8-bit OTP microcontroller based on the 80C51 architecture, featuring 16 KB on-chip OTP program memory, 512 B RAM, four 8-bit I/O ports, three 16-bit timers (T0/T1/T2), a full-duplex enhanced UART with framing error detection, and a Programmable Counter Array (PCA) supporting PWM and capture/compare functions. It operates at 2.7–5.5 V and delivers up to 33 MHz performance in 12-clock mode - ideal for motor control, industrial timing, and embedded instrumentation requiring deterministic real-time I/O.

For engineers reviewing the P87C51RB2BN,112 datasheet, P87C51RB2BN,112 pinout, P87C51RB2BN,112 application, or P87C51RB2BN,112 equivalent, this page provides verified technical context, validated pin-level circuit roles, confirmed low-power operating modes (Idle/Power-down), exact OTP memory mapping, and direct alternative options with documented functional alignment and known trade-offs in clock configuration and peripheral availability.

Technical Context

The P87C51RB2BN,112 implements a static CMOS 80C51 core with full instruction set compatibility and adds hardware enhancements including a 5-level nested interrupt structure (7 sources, 4 priority levels), dual data pointers, security bits (3-bit encryption array), and programmable clock-out via Timer 2. Its PCA module supports five independent CEX channels (CEX0–CEX4) for simultaneous PWM generation and edge-triggered capture.

It supports selectable 6-clock or 12-clock operation via OTP bit OX2 (factory-programmed default: 12-clock) and SFR bit X2 (CKCON.0), enabling software-switchable throughput scaling. Clock-out frequency ranges from 61 Hz to 4 MHz (12-clock) or 122 Hz to 8 MHz (6-clock) at 16 MHz crystal, derived from RCAP2H/L reload values without interrupt generation.

Key Specifications

Pinout & Package

Package: 40-pin Plastic Dual In-Line Package (PDIP), SOT129-1, commercial temperature range (0 °C to +70 °C).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with AT89C51RC2-24PU and P89V51RD2BN,112, the P87C51RB2BN,112 offers optimal balance of OTP security, deterministic PCA timing, and legacy system compatibility - making it preferred for cost-sensitive, fixed-function industrial controllers where code immutability and EMI resilience are critical.

Availability

P87C51RB2BN,112 is available at Aetrix Electronics and suitable for motor control systems, industrial data loggers, legacy equipment retrofits, and embedded test fixtures requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for P87C51RB2BN,112 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

NXP Semiconductors acquired Philips Semiconductors in 2006 and continues to support legacy 80C51 derivatives with documentation, cross-reference tools, and authorized distribution channels.

The P87C51RB2BN,112 belongs to the P87C51RA2/RB2/RC2/RD2 OTP microcontroller family, designed specifically for cost-sensitive, high-reliability embedded applications demanding low-voltage operation, deterministic real-time I/O, and long-lifecycle availability in industrial and instrumentation markets.

FAQ

What is the maximum operating frequency of the P87C51RB2BN,112 at 5 V?

The P87C51RB2BN,112 supports up to 33 MHz in 12-clock mode and 30 MHz in 6-clock mode at 5 V. The actual achievable frequency depends on the selected clock mode (configured via OTP bit OX2 and SFR bit X2), with 6-clock mode delivering twice the instruction throughput per MHz compared to standard 80C51 devices. This makes the P87C51RB2BN,112 suitable for time-critical motor control loops requiring sub-microsecond response.

Does the P87C51RB2BN,112 support in-system programming (ISP)?

No, the P87C51RB2BN,112 uses One-Time-Programmable (OTP) memory and requires parallel programming via a dedicated programmer before soldering. It does not support in-system programming or UART-based firmware updates. Programming is performed through the standard 87C51-compatible interface using VPP (EA pin) and control signals - a key differentiator from Flash-based alternatives like the P89V51RD2BN,112. This ensures firmware integrity in safety-critical deployments.

How many PWM channels does the P87C51RB2BN,112 provide, and how are they implemented?

The P87C51RB2BN,112 provides five independent PWM outputs via its Programmable Counter Array (PCA) module - CEX0 through CEX4 on Port 1 pins P1.3–P1.7. Each channel supports 16-bit resolution, configurable polarity, and edge-aligned or center-aligned modes. PWM generation is hardware-autonomous and does not consume CPU cycles, enabling concurrent execution of communication tasks and real-time control algorithms within the P87C51RB2BN,112.

Can the P87C51RB2BN,112 operate from a 3 V supply, and what is its minimum guaranteed frequency?

Yes, the P87C51RB2BN,112 is fully specified for operation from 2.7 V to 5.5 V. At 3 V, its maximum guaranteed frequency is 16 MHz in both 6-clock and 12-clock modes, as confirmed in the Selection Table. This enables reliable operation in battery-powered instrumentation where supply voltage sags below 3.3 V, while maintaining sufficient timing resolution for UART communication and sensor sampling at 9600–115200 baud.

What low-power modes are supported by the P87C51RB2BN,112, and how is wake-up achieved from Power-down mode?

The P87C51RB2BN,112 supports Idle mode (CPU halted, peripherals active) and Power-down mode (oscillator stopped, RAM retained). Wake-up from Power-down requires either a hardware reset or a level-sensitive external interrupt on INT0 or INT1. The interrupt pin must be held low to restart the oscillator and then brought high to complete exit - ensuring synchronized resumption of code execution after RETI. This behavior is explicitly defined in the Power-Down Mode section of the P87C51RB2BN,112 datasheet.