W78I052DFG - 8KB 40MHz 8051 MCU | Nuvoton | BQFP-44
MPN: W78I052DFG ✓ ActiveW78I052DFG Overview
An 8051 microcontroller is an 8-bit embedded-processing component within the broader microcontroller and semiconductor hierarchy. It integrates program memory, data memory, digital I/O, timers, serial communication functions, and interrupt control into one package. Compared with larger 32-bit microcontrollers, the W78I052DFG focuses on deterministic control of digital systems with modest flash requirements, lower implementation complexity, and a broad base of compatible development tools and peripherals.
The verified key characteristics are 8KB Flash, 40MHz operation, 2.4V-to-5.5V supply voltage, 256 bytes of RAM, and a 44-pin BQFP package. These values position the device for embedded products that require more general-purpose firmware storage than a very small 8-bit controller while retaining the cost and simplicity associated with the 8051 architecture. The 40MHz clock rating provides additional execution headroom for protocol handling and multi-task control.
Within the Nuvoton W78 8-bit product family, the W78E052D is a closely related 8051 MCU described as configurable and pin-compatible with traditional 12T 8051 devices. Its documented operating range is also 2.4V to 5.5V at -40°C to 85°C. Available family packages include PQFP-44 and other form factors, so the DFG package suffix and footprint must be checked carefully before treating a related W78E052D ordering code as a board-level replacement.
Typical application directions include security and alarm controllers, barcode-reader interfaces, keyboard and telephone user-interface modules, KVM equipment, and compact industrial-control panels. These systems benefit from the MCU's 8KB Flash, 256-byte RAM, multiple I/O pins, and ability to operate across a voltage range compatible with 5V-oriented embedded logic.
PCB design should preserve the exact PQFP-44/BQFP-44 footprint, pin assignment, oscillator requirements, reset behavior, and decoupling requirements from the applicable Nuvoton datasheet. Because the supplied search data does not expose the complete pin table or confirmed replacement matrix, engineers should verify pin-level continuity and peripheral multiplexing before production substitution.
This page consolidates the verified distributor specifications, package information, pricing evidence, related-family references, and practical engineering caveats. It also distinguishes confirmed drop-in candidates from family-level options that still require schematic, footprint, clock, and peripheral compatibility checks.
Drop-in alternatives for W78I052DFG — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with W78I052DFG (same form factor and footprint) — differing in Architecture, Maximum Clock Frequency, Microcontroller Type, Mounting Type, Operating Voltage Range.
W78E052DFG
✅ Drop-InContact for price
View Datasheet →W78E052DDG
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →W78I052D
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
W78E051D
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
W78E052A
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
W78I052DFG Maximum Ratings & Electrical Characteristics
| Microcontroller Type | 8-bit 8051-family microcontroller |
| Architecture | 51 Series |
| Flash Memory | 8KB |
| RAM | 256 Byte |
| Maximum Clock Frequency | 40MHz |
| Operating Voltage Range | 2.4V to 5.5V |
| Operating Temperature Range | -40°C to 85°C |
| Package | 44-pin BQFP |
| Package Family | PQFP-44 (10x10 mm) |
| Mounting Type | Surface Mount |
| Lead-Free Status | Pb-free |
| RoHS Status | Compliant |
| Program Memory Type | FLASH |
W78I052DFG pqfp-44 (10x10 mm) Pin Configuration Guide
Pin configuration for W78I052DFG (pqfp-44 (10x10 mm) 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 W78I052DFG.
Refer to the datasheet for full pin configuration.
Typical Applications
W78I052DFG is suitable for 6 applications: Security and Alarm Controllers, Barcode Reader Interfaces, KVM Control Modules, Key Telephone User Interfaces, Compact Industrial Control Panels, Human-Interface Embedded Products.
Security and Alarm Controllers
The W78I052DFG fits compact security and alarm-control modules because its 8KB Flash provides room for control firmware, while its 256-byte RAM and 40MHz clock support responsive state-machine handling. The 2.4V-to-5.5V operating range permits integration with common low-voltage and 5V peripheral arrangements. In a practical alarm panel, the MCU can supervise sensors, drive indicators, and coordinate keypad events. The 44-pin BQFP package also offers more connection options than a small-package 8051. Before layout approval, engineers should verify the exact I/O assignments, interrupt sources, oscillator arrangement, and reset behavior from the Nuvoton datasheet, since those details were not included in the supplied distributor excerpts.
Recommended
Barcode Reader Interfaces
W78I052DFG is suitable for a barcode-reader interface because barcode scanners commonly require deterministic digital control, serial communication, and compact firmware rather than a high-performance application processor. The MCU's 40MHz maximum clock provides execution margin for decoding support, status handling, and communication routines, while 8KB Flash stores the device's control program. It can be placed between a scan engine and a host interface, translating trigger, data-ready, and error signals. The exact UART or other serial-resource configuration must be confirmed from the datasheet. Engineers should also account for the 256-byte RAM limit, external I/O levels, and the need for local bypass capacitors around the 2.4V-to-5.5V supply rail.
Recommended
KVM Control Modules
The W78I052DFG can serve as the controller in a compact KVM module that coordinates keyboard, video, or peripheral selection signals. Its 8KB Flash is appropriate for self-contained firmware handling switch states, LEDs, button inputs, and a communication protocol, and the 40MHz clock supports deterministic multitasking. The 44-pin BQFP package provides a practical number of external connections for control outputs and status indicators. A production design should verify whether all required UART, timer, and interrupt resources are simultaneously available. Signal conditioning may also be needed for the selected interface, while the 2.4V-to-5.5V range and -40°C-to-85°C rating support mainstream industrial operating environments without requiring an extended-temperature variant.
Recommended
Key Telephone User Interfaces
W78I052DFG is appropriate for key-phone and telephone user-interface modules that must scan keys, update displays, control indicators, and respond to call or hook events. The microcontroller's 8KB Flash can retain keypad mapping, state-machine code, and sound-control routines, while 40MHz operation provides useful timing headroom for debouncing and display updates. Its 44-pin BQFP package allows a practical number of I/O connections for keys and indicators. Designers should confirm the available timer channels, serial functions, and interrupt mapping against the actual firmware requirements. The 256-byte RAM may require careful buffer management, and the board must maintain clean power and clock signals across the full 2.4V-to-5.5V supply range.
Recommended
Compact Industrial Control Panels
The W78I052DFG is suitable for compact industrial control panels that monitor discrete inputs and operate relays, lamps, or other digital actuators. Its 8KB Flash supports a focused control program, and the 40MHz clock allows responsive debouncing and state updates. The -40°C-to-85°C rating covers many industrial environments, while the 2.4V-to-5.5V operating range supports common embedded supply levels. The 44-pin BQFP package provides a larger I/O and power-pin budget than the smallest controller packages. Designers should use the manufacturer pin map to allocate I/O, avoid loading outputs beyond their specified drive limits, and isolate inductive or high-current actuator paths from the MCU. Exact I/O counts and timing characteristics are not present in the supplied excerpts and must be verified before schematic release.
Recommended
Human-Interface Embedded Products
W78I052DFG can support human-interface products such as keypad controllers, menu panels, and compact equipment-control modules. Its 8KB Flash is sufficient for many focused firmware workloads, and its 40MHz maximum clock helps maintain responsive interaction without a more complex processor. The 44-pin BQFP package accommodates keypad scanning, display-control outputs, indicators, and serial communication. Because the device has 256 bytes of RAM, the firmware should use buffers carefully and avoid unnecessary simultaneous display copies. Hardware design should account for switch-bounce timing, connector protection, and logic-level compatibility with the attached display or keypad. The confirmed -40°C-to-85°C range and 2.4V-to-5.5V supply specification support many commercial and industrial implementations, subject to the missing pin and peripheral details being checked in the datasheet.
Recommended
Recommended Products Summary
Engineering reference data for W78I052DFG — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | W78E052DFG | W78E052D | W78I052D | W78E051D | W78E052A |
|---|---|---|---|---|---|---|
| Package | PQFP-44 (10x10 mm) | PQFP-44 (10x10 mm) | PQFP-44 (10x10 mm) | PQFP-44 (10x10 mm) | PQFP-44 (10x10 mm) | PQFP-44 (10x10 mm) |
| Brand | Nuvoton | Nuvoton | Nuvoton | Nuvoton | Nuvoton | Nuvoton |
| Processor Architecture | 8-bit 8051-family | Configurable 6T/12T 8051 | Configurable 6T/12T 8051 | 8051-family | W78E 8051-family | W78E052 8051-family |
| Operating Voltage Range | 2.4V to 5.5V | 2.4V to 5.5V | 2.4V to 5.5V | 2.4V to 5.5V | 2.4V to 5.5V | 2.4V to 5.5V |
| Operating Temperature Range | -40°C to 85°C | -40°C to 85°C | -40°C to 85°C | -40°C to 85°C | -40°C to 85°C | -40°C to 85°C |
| Special Configuration | W78I052 family | Configurable 6T/12T 8051 | Configurable 6T/12T 8051 | W78I052 family | W78E051 family | W78E052A family |
Key Differentiators
- Directly verified 8KB Flash configuration (vs W78E051D)
- Explicit 40MHz maximum operating frequency (vs W78E052A)
- Documented 44-pin BQFP package (vs W78E052D)
- Same 2.4V-to-5.5V and -40°C-to-85°C operating envelope (vs W78E052DFG)
Design Notes
Treat W78I052DFG as a PQFP-44/BQFP-44 surface-mount device with a 10x10 mm body. Place the decoupling capacitor or capacitors directly between the device supply and ground pins, keep the loop short, and route high-current return paths away from clock and sensitive control inputs. Because the canonical SVG library provided for this task has no PQFP-44 or LQFP-44 key, the package diagram uses the default key; engineers must use the Nuvoton mechanical drawing and exact DFG land pattern rather than a generic QFP template.
Do not assume that every W78-family 44-pin device is a drop-in replacement merely because its package outline matches. W78E052DFG and W78E052D are described as configurable 6T/12T 8051 devices, while W78I052DFG is the specified W78I052 device. Before substitution, compare every power and ground pin, oscillator pins, reset input, interrupt-capable pins, serial functions, timer channels, I/O direction, pull states, and any programming or test pins. Also recompile and test the firmware because instruction timing and register organization can differ across 6T and 12T configurations.
Route the oscillator and reset networks away from switching nodes and noisy peripheral outputs, and provide local return paths for every supply connection in the 44-pin footprint. If the MCU drives relays, lamps, display lines, or long cables, separate those outputs from sensitive timing and communication nets. Verify external logic levels because the device supports a 2.4V-to-5.5V operating range, but the exact I/O thresholds, output-drive ratings, and maximum transition rates were not included in the supplied verified excerpts and must be obtained from the manufacturer datasheet.
Design the supply for the full 2.4V-to-5.5V operating range, including voltage tolerance, startup ramp, and transient behavior. Place bulk capacitance near the source or power-entry point and local high-frequency bypass at the MCU pins. Do not use the catalog listing as evidence of a safe continuous-current or power-dissipation rating. Check the datasheet for internal-block current, I/O loading, and operating conditions at 40MHz because those values were not present in the supplied search data.
Compliance Information
The verified LCSC listing marks W78I052DFG RoHS compliant, while the Mouser listing identifies it as Pb-free. No explicit REACH, halogen-free, conflict-minerals, or automotive-qualification statement was provided. AEC-Q100 is not applicable based on the absence of an automotive qualification claim.
