W78L801A24FL - 8-Bit 24MHz 44-Pin Microcontroller | Nuvoton
MPN: W78L801A24FL ✗ End of LifeW78L801A24FL Overview
An 8051 microcontroller is a small, instruction-set-oriented embedded controller used to supervise sensors, switches, displays, communication peripherals, and actuator logic. The 8051 family combines a CPU core, program memory, data memory, timers, serial interfaces, and GPIO functions in one integrated circuit. Because the W78L801A24FL belongs to this established embedded-control category, it is useful for designs that value compact instruction execution, deterministic peripheral control, and broad software familiarity.
The device is identified as an 8-bit MCU with 4 KB MROM and a maximum clock frequency of 24 MHz. Its stated operating voltage range of 1.8 V to 5.5 V supports both low-voltage and conventional 5 V system rails. One distributor listing also identifies the family as 51-series, reinforcing its 8051-compatible positioning. The package is specified as QFP-44 in a 10 mm by 10 mm surface-mount format, while another listing describes the package as 44-BQFP.
Typical embedded uses include appliance controls, small industrial modules, keypads, LED indicators, sensor-conditioning front ends, programmable logic controllers, and compact consumer products. The 24 MHz operating rate supports timing-intensive control tasks, while the 8-bit architecture is most appropriate when the application is dominated by GPIO, timers, serial communication, and simple state-machine control rather than intensive arithmetic or large graphical interfaces.
When laying out a W78L801A24FL board, use the manufacturer pin description table to assign every signal and preserve the exposed-pad, power, ground, clock, reset, and programming connections. Confirm the oscillator frequency, decoupling requirements, and programming interface against the manufacturer datasheet before releasing the PCB. This page combines the available device characteristics with practical application guidance, package information, sourcing support, and an honest comparison framework for engineers evaluating this 8051-family MCU.
Drop-in alternatives for W78L801A24FL — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
No drop-in alternatives available for this product.
Request AlternativesW78L801A24FL Maximum Ratings & Electrical Characteristics
| Microcontroller Type | 8-bit MCU |
| Architecture | 8051-compatible CISC |
| Product Family | 51 series |
| Program Memory | 4 KB MROM |
| Maximum Clock Frequency | 24 MHz |
| Operating Voltage Range | 1.8 V to 5.5 V |
| Package | QFP-44 (10 x 10 mm) |
| Package Type | 44-BQFP |
| Mounting Type | Surface mount |
| Pin Count | 44 pins |
| Manufacturer Identification | Nuvoton Technology Corporation / Winbond datasheet identification |
| Operating Voltage Reference | 2.5 V / 3.3 V / 5 V |
| RoHS Status | RoHS |
| Datasheet Description | 8-bit microcontroller |
| Datasheet Document Length | 24 pages |
| Datasheet File Size | 309 KB |
| Catalog Identifier | C2640542 |
W78L801A24FL 44-bqfp Pin Configuration Guide
Pin configuration for W78L801A24FL (44-bqfp 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 W78L801A24FL.
Refer to the datasheet for full pin configuration.
Typical Applications
W78L801A24FL is suitable for 6 applications: Appliance Control, Keypad and Human-Interface Control, Industrial Sensor Interface, LED and Status-Indicator Control, Programmable Logic Controller, Communication Gateway Module.
Appliance Control
The W78L801A24FL fits appliance-control boards that coordinate buttons, indicators, relays, and timing functions through a compact 8051-compatible MCU. Its 24 MHz maximum clock provides headroom for deterministic control tasks, while 4 KB of MROM supports a focused program for a single appliance function. The 1.8 V to 5.5 V range accommodates low-voltage logic as well as conventional 5 V systems. A designer should verify every relay driver and load interface because the MCU is intended to control peripherals rather than power them directly.
Recommended
Keypad and Human-Interface Control
A keypad, access panel, or programmable control keypad can use the W78L801A24FL to scan inputs, manage debounce timing, update indicators, and control an external display or communications module. The 8051-compatible 8-bit architecture is appropriate for state-machine-heavy human-interface tasks, and the 24 MHz clock supports responsive timing. The 44-pin QFP provides a useful mix of digital I/O for switch matrices and peripherals. Firmware should define debounce behavior and port ownership before assigning pins, and the manufacturer pin table must govern the final layout.
Recommended
Industrial Sensor Interface
The W78L801A24FL can act as the supervisory controller for a compact sensor interface that converts switch, contact, or digital-sensor signals into system actions. Its 4 KB MROM is suitable for firmware focused on acquisition sequencing, threshold management, fault flags, and communication handling rather than large data storage. The 1.8 V to 5.5 V range simplifies mixed-voltage designs, but external sensors still need suitable level translation and protection. Confirm timer and serial-interface requirements in the datasheet before selecting it for a new measurement platform.
Recommended
LED and Status-Indicator Control
The W78L801A24FL is suitable for managing LED arrays, status lamps, and sequencing indicators in compact instruments. Timer-driven firmware can produce stable blink rates and diagnostic patterns while GPIO outputs control the lighting elements, and the 24 MHz clock provides ample timing margin for multiplexing. The low-voltage operating range supports portable and embedded products, while the 44-pin package offers enough I/O for multiple indicators and communication pins. Use current-limiting resistors or constant-current drivers and confirm absolute pin limits from the manufacturer datasheet.
Recommended
Programmable Logic Controller
A small PLC or embedded logic module can use the W78L801A24FL for deterministic input scanning, output sequencing, timers, and local diagnostics. The familiar 8051-compatible architecture simplifies migration for engineers with existing 51-series code, while 4 KB of MROM is appropriate for a focused control program. Its 24 MHz maximum clock and 1.8 V to 5.5 V supply range fit compact controller boards. Before production, verify industrial temperature grade, isolation needs, watchdog behavior, and expansion interfaces against current manufacturer documentation.
Recommended
Communication Gateway Module
The W78L801A24FL can support a small protocol-conversion or gateway module that reads local inputs, manages status indicators, and coordinates a serial link. Its 8051-compatible core and timer resources are well matched to compact protocol handling, while 4 KB of MROM requires disciplined code organization for larger gateway functions. The 1.8 V to 5.5 V range allows integration with low-power interface sections. Use the manufacturer documentation to confirm UART or other serial capabilities, interrupt behavior, and pin multiplexing before assigning the communications connector.
Recommended
Recommended Products Summary
Engineering reference data for W78L801A24FL — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product |
|---|---|
| Package | QFP-44 (10 x 10 mm) |
| Brand | Nuvoton |
| Architecture | 8051-compatible CISC |
| Program Memory | 4 KB MROM |
| Maximum Clock Frequency | 24 MHz |
| Operating Voltage Range | 1.8 V to 5.5 V |
| Product Family | 51 series |
| RoHS Status | RoHS |
Key Differentiators
- Broad low-voltage operating range (vs A conventional 5 V-only 51-series MCU)
- 24 MHz processing clock (vs A lower-frequency 8-bit MCU)
- Integrated 8051-compatible control platform (vs A discrete digital controller)
Design Notes
Use the manufacturer package drawing and pin-description table as the controlling references for all 44 connections. Place required bypass capacitors close to the associated supply pins, route oscillator traces away from switching nodes and communication inputs, and reserve programming access unless the production fixture uses test pads.
Design the supply rail for the selected operating point within the documented 1.8 V to 5.5 V range. Confirm the startup behavior, required decoupling, I/O drive limits, and any brownout or reset interaction in the datasheet; logic peripherals and pull-up networks must also be compatible with the selected voltage.
Do not assume that every 51-series MCU is interchangeable with the W78L801A24FL. Memory organization, port mapping, oscillator options, interrupt vectors, peripheral registers, programming signals, and package functions can differ. Review the complete pin table and migration requirements before approving a substitute.
Compliance Information
The catalog listing identifies the W78L801A24FL as RoHS. Other compliance declarations are not stated in the available product information.
