NXP Semiconductors P87C51FB-4B,557

Overview

P87C51FB-4B,557 from Philips Semiconductors is an 8-bit OTP microcontroller in the 8XC51FA/FB/FC family, featuring 16 KB on-chip program memory, 256 bytes RAM, programmable PCA (Programmable Counter Array), and full-duplex enhanced UART. It operates at up to 16 MHz across 2.7–5.5 V and targets embedded control applications requiring precise timing, motor control, and serial communication.

For engineers reviewing the P87C51FB-4B,557 datasheet, P87C51FB-4B,557 pinout, P87C51FB-4B,557 application, or P87C51FB-4B,557 equivalent, this device supports 4-level priority interrupts, asynchronous port reset, low-EMI ALE inhibition, and external memory expansion up to 64 KB - critical for industrial I/O, legacy system upgrades, and cost-sensitive 8051-based designs.

Technical Context

The P87C51FB-4B,557 implements an enhanced 80C51 core with static CMOS design enabling 0–16 MHz operation and three power modes: Idle, Stop Clock, and Power Down. Its PCA module provides five independent capture/compare channels (CEX0–CEX4) supporting PWM generation, high-speed input capture, and software-timed event counting.

It integrates a multi-source, four-priority nested interrupt structure with six interrupt sources (INT0, INT1, T0, T1, RxD/TxD, PCA), full-duplex UART with framing error detection and automatic address recognition, and dual DPTR registers for efficient external memory access - all compatible with standard 8051 instruction set and toolchains.

Key Specifications

Pinout & Package

Package: 44-pin Plastic Quad Flat Pack (PQFP), SOT307-2 footprint, 10 mm × 10 mm body, 0.8 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with P87C51FA-4B,557 and P87C51FC-4B,557, the P87C51FB-4B,557 delivers optimal balance of memory capacity (16 KB), pin compatibility, and cost for mid-complexity 8051-based control systems - avoiding underutilized flash in smaller variants or over-provisioning in larger ones.

Availability

P87C51FB-4B,557 is available at Aetrix Electronics and suitable for industrial motor control, legacy system upgrades, smart sensor nodes, and embedded serial gateways requiring stable component supply and long-term manufacturability.

Supply support for P87C51FB-4B,557 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 global leader in high-reliability analog and mixed-signal ICs, with deep heritage in 8-bit microcontrollers and industrial interface solutions.

The 8XC51FA/FB/FC product line was designed specifically for cost-sensitive, pin-compatible upgrades of legacy 8051 systems - delivering enhanced peripherals (PCA, enhanced UART), wider voltage range (2.7–5.5 V), and OTP security while maintaining full instruction-set and toolchain compatibility.

FAQ

What is the maximum operating frequency of the P87C51FB-4B,557?

The P87C51FB-4B,557 supports a maximum clock frequency of 16 MHz across its full 2.7–5.5 V supply range. This corresponds to a 62.5 ns instruction cycle time for single-cycle instructions. Operation above 16 MHz is not supported - unlike higher-speed variants such as the P87C51FB-IB which runs up to 33 MHz but requires 5 V only.

Does the P87C51FB-4B,557 include a hardware watchdog timer?

No, the P87C51FB-4B,557 does not integrate a hardware watchdog timer. That feature is introduced in the later 8XC51RA+/RB+/RC+/RD+ family (e.g., P87C51RA+-4B). The P87C51FB-4B,557 relies on software-based timeout supervision or external watchdog ICs for system reliability.

What package type and pin count does the P87C51FB-4B,557 use?

The P87C51FB-4B,557 uses a 44-pin Plastic Quad Flat Pack (PQFP) with SOT307-2 mechanical outline. It is not available in DIP or PLCC packages - those are assigned to other variants like P87C51FB-4N (40-pin DIP) or P87C51FB-4A (44-pin PLCC).

Can the P87C51FB-4B,557 execute code from external memory?

Yes, the P87C51FB-4B,557 can execute code from external program memory when the EA/VPP pin is held low. When EA is high, it executes exclusively from its internal 16 KB OTP up to address 3FFFH; addresses beyond that will fetch from external memory regardless of EA state.

How many capture/compare channels does the PCA module in the P87C51FB-4B,557 support?

The P87C51FB-4B,557 includes a 5-channel PCA module, with dedicated pins CEX0 through CEX4 mapped to P1.3–P1.7. Each channel supports independent capture, compare, PWM, and software timer modes - enabling simultaneous motor phase control, pulse measurement, and periodic event generation.