W79E9781AKG - 8-bit MCU 64KB Flash | Nuvoton | Industrial
MPN: W79E9781AKG ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.75 | $3.75 |
| 10 | $3.38 | $33.80 |
| 100 | $2.99 | $299.00 |
| 500 | $2.69 | $1,345.00 |
| 1,000 | $2.4 | $2,400.00 |
W79E9781AKG Overview
An 8-bit microcontroller (MCU) is a microprocessor-on-a-chip that integrates a CPU, program memory, data RAM, and peripherals into a single IC. The 8-bit architecture is optimized for cost-sensitive, low-power, deterministic control tasks; in the system hierarchy an MCU sits between discrete logic ICs and 32-bit microprocessors, providing firmware-driven I/O handling, sensor interfacing, and protocol conversion. Nuvoton's W79 family extends the legacy 8051 instruction set with Turbo-MCU enhancements, doubling the standard clock-per-instruction cycle for higher throughput at the same crystal frequency.
Key features include 64 KB of in-system programmable (ISP) Flash allowing field firmware updates via UART, an operating voltage range of 2.4V to 5.5V that supports both 3.3V and 5V rails, and an industrial-grade operating temperature of -40C to +85C. The on-chip 10-bit ADC provides up to 8 analog input channels, while the four 16-bit timer/counters support PWM generation, capture, and event counting. A dedicated hardware watchdog and brown-out reset circuit protect against code lockup and unstable supplies.
The W79E9781AKG uses the standard 8051 instruction set with Nuvoton Turbo-MCU extensions, allowing one machine cycle per clock rather than the original 12, while preserving binary compatibility with legacy 8051 firmware. The device's ISP mechanism boots from a ROM-resident bootloader that re-programs the Flash via the UART pins, eliminating external programming hardware during prototyping and field service.
Typical applications include industrial control panels, home appliance main boards, motor control BLDC drivers, smart meter data concentrators, and point-of-sale terminals. The integrated ADC, timers, and UART let designers replace multiple discrete components with a single chip, shrinking BOM cost and PCB area.
When designing with this device, plan ISP access by routing the UART pins to a header or optocoupler-isolated connector. Use the brown-out detector level matched to the lowest reliable rail voltage (typically 2.7V for 3.3V systems) to prevent Flash corruption during power-down events.
This page consolidates distributor pricing, package-level drop-in alternatives, and engineering design notes that go beyond the manufacturer datasheet, supporting faster component selection and risk-aware substitution decisions.
Drop-in alternatives for W79E9781AKG — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
W79E9783AKG
✅ Drop-In📋 Reference alternative (not in catalog)
W79E9791AKG
✅ Drop-In📋 Reference alternative (not in catalog)
W79E6325AKG
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
W79E9781AKG Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit 8051 (Turbo-MCU) |
| Instruction Set | 8051-compatible with Nuvoton extensions |
| Program Memory (Flash) | 64 KB |
| SRAM | 1.25 KB |
| Operating Voltage Range | 2.4 V to 5.5 V |
| Maximum Clock Frequency | 40 MHz |
| ADC | 10-bit, up to 8 channels |
| Timers | 4 x 16-bit |
| Watchdog Timer | Yes |
| Brown-Out Detector | Yes |
| UART | 1 x hardware full-duplex |
| I2C / SPI | I2C master + SPI master |
| Operating Temperature | -40 C to +85 C |
| Package | LQFP-128 |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| In-System Programming | Yes (UART bootloader) |
W79E9781AKG lqfp-128 Pin Configuration Guide
Pin configuration for W79E9781AKG (lqfp-128 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 W79E9781AKG.
Refer to the datasheet for full pin configuration.
Typical Applications
W79E9781AKG is suitable for 6 applications: Industrial Control Panels, Home Appliance Main Boards, BLDC Motor Drivers, Smart Meter Data Concentrators, Point-of-Sale Terminals, Sensor Hubs and IoT Edge Nodes.
Industrial Control Panels
The W79E9781AKG fits industrial control panels because its 64 KB ISP Flash and 1.25 KB SRAM handle menu-driven HMI logic, while the 10-bit ADC reads analog sensor inputs such as temperature and pressure. The wide 2.4-5.5V supply tolerates noisy 24V-derived industrial rails after regulation, and the -40C to +85C operating temperature covers factory floor environments. The hardware watchdog and brown-out detector protect against code lockup and supply sag, critical for unattended control cabinets.
Recommended
Home Appliance Main Boards
The W79E9781AKG suits home appliance main boards - washing machines, microwave ovens, and air conditioners - where its 8051-compatible core simplifies firmware reuse across product lines. The four 16-bit timers drive PWM outputs for motor and heater control, while the hardware UART links to display modules or Wi-Fi companion modules. ISP via UART allows field firmware updates without disassembly, a strong advantage for appliance OEMs managing long product lifecycles.
Recommended
BLDC Motor Drivers
The W79E9781AKG supports low-to-mid complexity BLDC motor drivers by using its 16-bit timers to generate 3-phase complementary PWM with dead-time insertion, and its 10-bit ADC to sample back-EMF for sensorless commutation. The 40 MHz Turbo-MCU core provides enough headroom for trapezoidal or simple sinusoidal control loops. The integrated brown-out detector prevents erratic motor behavior during supply transients common in motor inrush events.
Recommended
Smart Meter Data Concentrators
The W79E9781AKG can serve as the local data concentrator in smart-meter networks, gathering pulses from electricity/water/gas meters and forwarding aggregated data via the hardware UART to a cellular or PLC modem. The 64 KB Flash accommodates DLMS/COSEM or proprietary metering stacks, while the watchdog timer guards against meter hangs. The industrial -40C to +85C rating handles outdoor meter cabinet conditions.
Recommended
Point-of-Sale Terminals
The W79E9781AKG handles the keyboard, display, and printer interface in low-cost point-of-sale terminals where cost dominates over raw processing speed. Its UART links to a mag-stripe or smartcard reader, its I2C/SPI master drives an LCD or thermal printer controller, and ISP via UART allows secure firmware updates at deployment sites. The 5V-tolerant I/O simplifies interfacing with legacy POS peripherals.
Recommended
Sensor Hubs and IoT Edge Nodes
The W79E9781AKG can act as an edge sensor hub aggregating analog and digital sensors and forwarding pre-processed data via UART to a higher-level gateway. The 10-bit ADC samples multiple sensor channels, the timers schedule periodic wake-and-measure cycles, and the brown-out detector preserves node state across brown-out events. ISP enables OTA-style field updates when paired with a companion wireless module.
Recommended
Recommended Products Summary
Engineering reference data for W79E9781AKG — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | W79E9783AKG | W79E9791AKG | W79E6325AKG |
|---|---|---|---|---|
| Brand | Nuvoton | Nuvoton | Nuvoton | Nuvoton |
| Package | LQFP-128 | LQFP-128 - same | LQFP-128 - same | LQFP-128 - same |
| Core | 8-bit 8051 Turbo | 8-bit 8051 Turbo | 8-bit 8051 Turbo | 8-bit 8051 |
Key Differentiators
- Wide 2.4V to 5.5V supply range (vs W79E6325AKG)
- Integrated ISP UART bootloader (vs Generic 8051 MCUs)
- 64 KB Flash on a 40 MHz Turbo-MCU core (vs W78E052D)
Design Notes
The W79E9781AKG operates from 2.4V to 5.5V; place a 10uF bulk capacitor plus a 0.1uF ceramic decoupling cap close to the VDD pins to suppress switching transients. Use the on-chip brown-out detector set to the minimum reliable rail voltage (e.g., 2.7V for a 3.3V system) to prevent Flash corruption during power-down events.
Route the ISP UART pins (TX, RX) to a header or optocoupler-isolated connector so that firmware can be updated in-circuit. Keep the UART traces short and away from switching power or motor driver traces to avoid bootloader-mode glitches during field programming.
Estimated: total Flash endurance is typically rated at 100K erase/write cycles - design firmware update flows to minimize unnecessary writes and avoid using Flash as a high-write-rate log. The watchdog timer must be refreshed periodically in firmware; failure to refresh will reset the device.
Compliance Information
RoHS compliant per Nuvoton product page. Standard variant is not AEC-Q100 qualified; for automotive choose the Q1 suffix variant. Halogen-free status not explicitly stated in provided data.
