W78E051DFG - 40MHz 8052 8-Bit MCU with 4KB Flash | Nuvoton
MPN: W78E051DFG ✗ End of LifeW78E051DFG Overview
An 8052 microcontroller is an embedded microcontroller architecture combining a small general-purpose CPU core with program memory, data memory, parallel I/O, serial communication, timers, and system-control peripherals. The W78E051 series belongs to the broader microcontroller category, which sits above processor cores and below embedded-control semiconductor solutions used in industrial products, appliances, access controls, and compact automation equipment.
The W78E051DFG provides 4 KB (4K x 8) of flash program memory for firmware storage and an operating speed of 40 MHz. Its listed peripherals include a power-on reset, watchdog timer, UART/USART interface, and external bus interface. The 36 available I/O pins provide substantial parallel connectivity for discrete inputs, output control, indicators, relays, and external interface signals without requiring a larger package.
The device operates from 2.4 V to 5.5 V and is specified for industrial temperature conditions from -40 °C to 70 °C. Flash memory allows firmware to remain resident without a separate external memory component, simplifying both PCB routing and production programming. The 40 MHz clock rate also gives the 8-bit CPU more instruction throughput than lower-frequency 8051-class devices while retaining the familiar programming model.
Typical uses include appliance controllers, keyboard and human-interface panels, access-control equipment, small motor or relay controllers, industrial interface modules, and compact embedded products. Its combination of 36 I/O pins, serial communication, external bus support, and watchdog protection is particularly useful when a design needs flexible parallel connectivity without a high-pin-count microcontroller package.
When designing around the W78E051DFG, verify every peripheral, clock option, interrupt vector, and electrical limit against the current manufacturer datasheet before schematic release. The supplied search evidence confirms the principal specifications but does not expose the complete pin map, memory map, timing diagrams, or electrical characteristics needed for a production design.
This page consolidates the verified distributor information, core MCU specifications, sourcing links, and design limitations for the W78E051DFG. It also separates confirmed facts from unavailable engineering data, helping engineers establish whether the 44-pin 8052-compatible device is appropriate before beginning a drop-in PCB or firmware evaluation.
Drop-in alternatives for W78E051DFG — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
No drop-in alternatives available for this product.
Request AlternativesW78E051DFG Maximum Ratings & Electrical Characteristics
| Microcontroller Type | 8-bit 8052-compatible microcontroller |
| Core Processor | 8052 |
| Core Size | 8-bit |
| Maximum Clock Frequency | 40 MHz |
| Program Memory Size | 4 KB (4K x 8) flash |
| Program Memory Type | Flash |
| Supply Voltage Range | 2.4 V to 5.5 V |
| Operating Temperature Range | -40 °C to 70 °C |
| Number of I/O Pins | 36 |
| Package | 44-pin QFP |
| Connectivity | EBI/EMI and UART/USART |
| Peripherals | Power-on reset and watchdog timer |
| Series | W78 |
| Lead-Free Status | Pb-free |
| Lifecycle Status | Not for new designs |
W78E051DFG 44-pin qfp Pin Configuration Guide
Pin configuration for W78E051DFG (44-pin qfp package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for W78E051DFG.
Refer to the datasheet for full pin configuration.
Typical Applications
W78E051DFG is suitable for 6 applications: Appliance Control Module, Access-Control and Reader Module, Keyboard and Human-Interface Controller, Small Relay and Actuator Controller, Industrial Serial Interface Module, Legacy 8052 Embedded Controller.
Appliance Control Module
The W78E051DFG fits compact appliance controllers that need an established 8052-compatible firmware base, 4 KB of flash for control code, and 36 I/O pins for switches, indicators, interlocks, and actuators. Its 40 MHz operating rate provides additional instruction headroom for debouncing, state-machine execution, and communication handling without moving to a larger processor. The verified 2.4 V to 5.5 V supply range is suitable for regulated embedded rails, although the complete absolute maximum and current-consumption data must be checked before selecting components. Because the device is marked not for new designs, it is best suited to maintenance or controlled extensions of an established 8052 platform rather than unrestricted volume production.
Access-Control and Reader Module
The W78E051DFG is suitable for access-control readers and credential-interface modules that combine several discrete inputs and outputs with a serial host interface. Its 36 I/O pins can support request-to-exit contacts, relay or lock-status inputs, LEDs, and other low-speed control signals, while the listed UART/USART provides a path to a system controller. The 4 KB flash capacity supports compact firmware for credential handling and event logic, and the watchdog timer can help recover the controller after a software fault. The Nuvoton W78E051DFG datasheet should be consulted for the exact peripheral pin assignments, electrical limits, and security requirements before deployment.
Keyboard and Human-Interface Controller
The W78E051DFG can serve as a keyboard, keypad, or compact human-interface controller because the verified 36 I/O pins provide ample parallel connections for switch matrices and status indicators. Its 40 MHz 8052-compatible core can scan inputs while maintaining control routines for LED feedback, host communication, or configuration storage. The 4 KB flash footprint is appropriate for tightly scoped firmware, and the integrated watchdog offers a practical recovery path for unattended peripherals. The supplied records do not expose RAM capacity, debounce hardware, or exact port behavior, so interface timing and memory budgeting must be verified against the manufacturer datasheet and, where necessary, measured on prototype hardware.
Small Relay and Actuator Controller
The W78E051DFG is a logical candidate for small relay, latch, or actuator-control boards where many digital outputs are needed alongside a supervisory serial link. Thirty-six I/O pins can distribute control and feedback signals, while UART/USART supports reporting to a higher-level controller and the watchdog timer improves recovery after a firmware fault. Its 2.4 V to 5.5 V operating range supports regulated embedded power systems, and the 40 MHz clock leaves processing margin for timing and debounce routines. Engineers must add appropriate driver, isolation, flyback, and protection components as required, and confirm that the MCU pins meet the load and surge conditions.
Industrial Serial Interface Module
The W78E051DFG can be used in a compact industrial interface module that translates between an external bus and a host or peripheral device. The verified feature set includes an external bus interface, UART/USART, power-on reset, and a watchdog timer, while 36 I/O pins provide status and control signals beyond the communication interfaces. The 40 MHz core and 4 KB flash are useful for protocol handling, address decoding, diagnostics, and local configuration logic. The supplied evidence does not state the external-bus timing, memory map, pin assignments, or electrical characteristics, so those values must be taken directly from the current Nuvoton manufacturer datasheet before layout release.
Legacy 8052 Embedded Controller
The W78E051DFG is particularly relevant to maintenance of legacy 8052-based embedded products where source-code compatibility and an established peripheral environment are more important than starting with a new MCU architecture. Its 8052 core, 4 KB flash, 36 I/O pins, UART/USART, and external bus interface align with common 8-bit control-controller designs, while the 40 MHz clock provides additional processing headroom. According to the verified distributor records, the part is not for new designs, so procurement should be treated as a controlled lifecycle decision. Confirm exact timing, reset behavior, peripheral registers, and programmer compatibility before transferring an existing firmware image.
Engineering reference data for W78E051DFG — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product |
|---|---|
| Brand | Nuvoton Technology Corporation |
| Package | 44-pin QFP |
| Core Processor | 8052 |
| Core Size | 8-bit |
| Maximum Clock Frequency | 40 MHz |
| Program Memory Size | 4 KB (4K x 8) |
| Program Memory Type | Flash |
| Supply Voltage Range | 2.4 V to 5.5 V |
| Operating Temperature Range | -40 °C to 70 °C |
| Number of I/O Pins | 36 |
| Connectivity | EBI/EMI and UART/USART |
| Peripherals | Power-on reset and watchdog timer |
Key Differentiators
- Established 8052-compatible control platform (vs ATMEGA328P-MUR)
- Integration of parallel and serial control resources (vs ATMEGA328P-MUR)
- Useful operating range for embedded products (vs ATMEGA328P-MNR)
Design Notes
The verified operating supply range is 2.4 V to 5.5 V, so design the power rail so that tolerance, startup overshoot, ripple, and transients remain inside the complete manufacturer absolute maximum ratings. Place local high-frequency bypass capacitance at the supply and ground pins using the values specified in the datasheet layout guidance. Because current-consumption figures and decoupling requirements were not included in the supplied records, do not infer them from the 40 MHz clock rating; confirm operating, idle, and peripheral current before selecting the regulator.
Reserve PCB space for the manufacturer's programming and debug interface even if production programming is planned, and verify oscillator, reset, and boot-option connections against the pin table. Keep the 44-pin QFP footprint mechanically centered and follow the manufacturer land pattern for pad length, width, and exposed thermal or underside features. No complete pinout was present in the supplied data, so routing must begin only after the authoritative package drawing and pin-assignment table have been obtained.
Do not assume that an 8052-compatible replacement can use the same firmware, peripheral registers, or pin mapping. The verified feature list confirms UART/USART, an external bus interface, reset, watchdog, 4 KB flash, and 36 I/O pins, but the supplied evidence does not describe timer counts, interrupt priorities, RAM size, or programming mode. Validate boot behavior, watchdog settings, bus timing, and peripheral initialization on target hardware before committing firmware to production.
Compliance Information
The Mouser record identifies W78E051DFG as Pb-free. No explicit RoHS, REACH, halogen-free, conflict-minerals, or automotive qualification statement was present in the supplied verified records, so those fields remain unknown.
